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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 568ca048e519747e1ea028d6a688171f91e0589e / . / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
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
854<p>An explicit alignment may be specified for a global. If not present, or if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]855 the alignment is set to zero, the alignment of the global is set by the
856 target to whatever it feels convenient. If an explicit alignment is
857 specified, the global is forced to have at least that much alignment. All
858 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]859
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]860<p>For example, the following defines a global in a numbered address space with
861 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]862
863<div class="doc_code">
864<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]865@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]866</pre>
867</div>
868
869</div>
870
871
872<!-- ======================================================================= -->
873<div class="doc_subsection">
874 <a name="functionstructure">Functions</a>
875</div>
876
877<div class="doc_text">
878
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]879<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]880 optional <a href="#linkage">linkage type</a>, an optional
881 <a href="#visibility">visibility style</a>, an optional
882 <a href="#callingconv">calling convention</a>, a return type, an optional
883 <a href="#paramattrs">parameter attribute</a> for the return type, a function
884 name, a (possibly empty) argument list (each with optional
885 <a href="#paramattrs">parameter attributes</a>), optional
886 <a href="#fnattrs">function attributes</a>, an optional section, an optional
887 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
888 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]889
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]890<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
891 optional <a href="#linkage">linkage type</a>, an optional
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]892 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]893 <a href="#callingconv">calling convention</a>, a return type, an optional
894 <a href="#paramattrs">parameter attribute</a> for the return type, a function
895 name, a possibly empty list of arguments, an optional alignment, and an
896 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]897
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]898<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]899 (Control Flow Graph) for the function. Each basic block may optionally start
900 with a label (giving the basic block a symbol table entry), contains a list
901 of instructions, and ends with a <a href="#terminators">terminator</a>
902 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]903
904<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]905 executed on entrance to the function, and it is not allowed to have
906 predecessor basic blocks (i.e. there can not be any branches to the entry
907 block of a function). Because the block can have no predecessors, it also
908 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]909
910<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]911 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]912
913<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]914 the alignment is set to zero, the alignment of the function is set by the
915 target to whatever it feels convenient. If an explicit alignment is
916 specified, the function is forced to have at least that much alignment. All
917 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]918
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]919<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]920<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]921<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]922define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]923 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
924 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
925 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
926 [<a href="#gc">gc</a>] { ... }
927</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]928</div>
929
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]930</div>
931
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]932<!-- ======================================================================= -->
933<div class="doc_subsection">
934 <a name="aliasstructure">Aliases</a>
935</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]936
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]937<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]938
939<p>Aliases act as "second name" for the aliasee value (which can be either
940 function, global variable, another alias or bitcast of global value). Aliases
941 may have an optional <a href="#linkage">linkage type</a>, and an
942 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]943
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]944<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]945<div class="doc_code">
946<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]947@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]948</pre>
949</div>
950
951</div>
952
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]953<!-- ======================================================================= -->
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]954<div class="doc_subsection">
955 <a name="namedmetadatastructure">Named Metadata</a>
956</div>
957
958<div class="doc_text">
959
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]960<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
961 nodes</a> (but not metadata strings) and null are the only valid operands for
962 a named metadata.</p>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]963
964<h5>Syntax:</h5>
965<div class="doc_code">
966<pre>
967!1 = metadata !{metadata !"one"}
968!name = !{null, !1}
969</pre>
970</div>
971
972</div>
973
974<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]975<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]976
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]977<div class="doc_text">
978
979<p>The return type and each parameter of a function type may have a set of
980 <i>parameter attributes</i> associated with them. Parameter attributes are
981 used to communicate additional information about the result or parameters of
982 a function. Parameter attributes are considered to be part of the function,
983 not of the function type, so functions with different parameter attributes
984 can have the same function type.</p>
985
986<p>Parameter attributes are simple keywords that follow the type specified. If
987 multiple parameter attributes are needed, they are space separated. For
988 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]989
990<div class="doc_code">
991<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]992declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]993declare i32 @atoi(i8 zeroext)
994declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]995</pre>
996</div>
997
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]998<p>Note that any attributes for the function result (<tt>nounwind</tt>,
999 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1000
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1001<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1002
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1003<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1004 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1005 <dd>This indicates to the code generator that the parameter or return value
1006 should be zero-extended to a 32-bit value by the caller (for a parameter)
1007 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1008
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1009 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1010 <dd>This indicates to the code generator that the parameter or return value
1011 should be sign-extended to a 32-bit value by the caller (for a parameter)
1012 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1013
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1014 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1015 <dd>This indicates that this parameter or return value should be treated in a
1016 special target-dependent fashion during while emitting code for a function
1017 call or return (usually, by putting it in a register as opposed to memory,
1018 though some targets use it to distinguish between two different kinds of
1019 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1020
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1021 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1022 <dd>This indicates that the pointer parameter should really be passed by value
1023 to the function. The attribute implies that a hidden copy of the pointee
1024 is made between the caller and the callee, so the callee is unable to
1025 modify the value in the callee. This attribute is only valid on LLVM
1026 pointer arguments. It is generally used to pass structs and arrays by
1027 value, but is also valid on pointers to scalars. The copy is considered
1028 to belong to the caller not the callee (for example,
1029 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1030 <tt>byval</tt> parameters). This is not a valid attribute for return
1031 values. The byval attribute also supports specifying an alignment with
1032 the align attribute. This has a target-specific effect on the code
1033 generator that usually indicates a desired alignment for the synthesized
1034 stack slot.</dd>
1035
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1036 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1037 <dd>This indicates that the pointer parameter specifies the address of a
1038 structure that is the return value of the function in the source program.
1039 This pointer must be guaranteed by the caller to be valid: loads and
1040 stores to the structure may be assumed by the callee to not to trap. This
1041 may only be applied to the first parameter. This is not a valid attribute
1042 for return values. </dd>
1043
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1044 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1045 <dd>This indicates that the pointer does not alias any global or any other
1046 parameter. The caller is responsible for ensuring that this is the
1047 case. On a function return value, <tt>noalias</tt> additionally indicates
1048 that the pointer does not alias any other pointers visible to the
1049 caller. For further details, please see the discussion of the NoAlias
1050 response in
1051 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1052 analysis</a>.</dd>
1053
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1054 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1055 <dd>This indicates that the callee does not make any copies of the pointer
1056 that outlive the callee itself. This is not a valid attribute for return
1057 values.</dd>
1058
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1059 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1060 <dd>This indicates that the pointer parameter can be excised using the
1061 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1062 attribute for return values.</dd>
1063</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1064
1065</div>
1066
1067<!-- ======================================================================= -->
1068<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1069 <a name="gc">Garbage Collector Names</a>
1070</div>
1071
1072<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1073
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1074<p>Each function may specify a garbage collector name, which is simply a
1075 string:</p>
1076
1077<div class="doc_code">
1078<pre>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1079define void @f() gc "name" { ... }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1080</pre>
1081</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1082
1083<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1084 collector which will cause the compiler to alter its output in order to
1085 support the named garbage collection algorithm.</p>
1086
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1087</div>
1088
1089<!-- ======================================================================= -->
1090<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1091 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1092</div>
1093
1094<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1095
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1096<p>Function attributes are set to communicate additional information about a
1097 function. Function attributes are considered to be part of the function, not
1098 of the function type, so functions with different parameter attributes can
1099 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1100
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1101<p>Function attributes are simple keywords that follow the type specified. If
1102 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1103
1104<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1105<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1106define void @f() noinline { ... }
1107define void @f() alwaysinline { ... }
1108define void @f() alwaysinline optsize { ... }
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1109define void @f() optsize { ... }
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1110</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1111</div>
1112
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1113<dl>
Charles Davisfaa8f752010-02-12 00:31:15 +0000[diff] [blame]1114 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1115 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1116 the backend should forcibly align the stack pointer. Specify the
1117 desired alignment, which must be a power of two, in parentheses.
1118
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1119 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1120 <dd>This attribute indicates that the inliner should attempt to inline this
1121 function into callers whenever possible, ignoring any active inlining size
1122 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1123
Jakob Stoklund Olesen77180732010-02-06 01:16:28 +0000[diff] [blame]1124 <dt><tt><b>inlinehint</b></tt></dt>
1125 <dd>This attribute indicates that the source code contained a hint that inlining
1126 this function is desirable (such as the "inline" keyword in C/C++). It
1127 is just a hint; it imposes no requirements on the inliner.</dd>
1128
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1129 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1130 <dd>This attribute indicates that the inliner should never inline this
1131 function in any situation. This attribute may not be used together with
1132 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1133
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1134 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1135 <dd>This attribute suggests that optimization passes and code generator passes
1136 make choices that keep the code size of this function low, and otherwise
1137 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1138
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1139 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1140 <dd>This function attribute indicates that the function never returns
1141 normally. This produces undefined behavior at runtime if the function
1142 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1143
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1144 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1145 <dd>This function attribute indicates that the function never returns with an
1146 unwind or exceptional control flow. If the function does unwind, its
1147 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1148
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1149 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1150 <dd>This attribute indicates that the function computes its result (or decides
1151 to unwind an exception) based strictly on its arguments, without
1152 dereferencing any pointer arguments or otherwise accessing any mutable
1153 state (e.g. memory, control registers, etc) visible to caller functions.
1154 It does not write through any pointer arguments
1155 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1156 changes any state visible to callers. This means that it cannot unwind
1157 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1158 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1159
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1160 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1161 <dd>This attribute indicates that the function does not write through any
1162 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1163 arguments) or otherwise modify any state (e.g. memory, control registers,
1164 etc) visible to caller functions. It may dereference pointer arguments
1165 and read state that may be set in the caller. A readonly function always
1166 returns the same value (or unwinds an exception identically) when called
1167 with the same set of arguments and global state. It cannot unwind an
1168 exception by calling the <tt>C++</tt> exception throwing methods, but may
1169 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1170
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1171 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1172 <dd>This attribute indicates that the function should emit a stack smashing
1173 protector. It is in the form of a "canary"&mdash;a random value placed on
1174 the stack before the local variables that's checked upon return from the
1175 function to see if it has been overwritten. A heuristic is used to
1176 determine if a function needs stack protectors or not.<br>
1177<br>
1178 If a function that has an <tt>ssp</tt> attribute is inlined into a
1179 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1180 function will have an <tt>ssp</tt> attribute.</dd>
1181
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1182 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1183 <dd>This attribute indicates that the function should <em>always</em> emit a
1184 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1185 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1186<br>
1187 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1188 function that doesn't have an <tt>sspreq</tt> attribute or which has
1189 an <tt>ssp</tt> attribute, then the resulting function will have
1190 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1191
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1192 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1193 <dd>This attribute indicates that the code generator should not use a red
1194 zone, even if the target-specific ABI normally permits it.</dd>
1195
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1196 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1197 <dd>This attributes disables implicit floating point instructions.</dd>
1198
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1199 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1200 <dd>This attribute disables prologue / epilogue emission for the function.
1201 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1202</dl>
1203
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1204</div>
1205
1206<!-- ======================================================================= -->
1207<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1208 <a name="moduleasm">Module-Level Inline Assembly</a>
1209</div>
1210
1211<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1212
1213<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1214 the GCC "file scope inline asm" blocks. These blocks are internally
1215 concatenated by LLVM and treated as a single unit, but may be separated in
1216 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1217
1218<div class="doc_code">
1219<pre>
1220module asm "inline asm code goes here"
1221module asm "more can go here"
1222</pre>
1223</div>
1224
1225<p>The strings can contain any character by escaping non-printable characters.
1226 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]1227 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1228
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1229<p>The inline asm code is simply printed to the machine code .s file when
1230 assembly code is generated.</p>
1231
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1232</div>
1233
1234<!-- ======================================================================= -->
1235<div class="doc_subsection">
1236 <a name="datalayout">Data Layout</a>
1237</div>
1238
1239<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1240
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1241<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1242 data is to be laid out in memory. The syntax for the data layout is
1243 simply:</p>
1244
1245<div class="doc_code">
1246<pre>
1247target datalayout = "<i>layout specification</i>"
1248</pre>
1249</div>
1250
1251<p>The <i>layout specification</i> consists of a list of specifications
1252 separated by the minus sign character ('-'). Each specification starts with
1253 a letter and may include other information after the letter to define some
1254 aspect of the data layout. The specifications accepted are as follows:</p>
1255
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1256<dl>
1257 <dt><tt>E</tt></dt>
1258 <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]1259 bits with the most significance have the lowest address location.</dd>
1260
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1261 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1262 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1263 the bits with the least significance have the lowest address
1264 location.</dd>
1265
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1266 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1267 <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]1268 <i>preferred</i> alignments. All sizes are in bits. Specifying
1269 the <i>pref</i> alignment is optional. If omitted, the
1270 preceding <tt>:</tt> should be omitted too.</dd>
1271
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1272 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1273 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1274 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1275
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1276 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1277 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1278 <i>size</i>.</dd>
1279
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1280 <dt><tt>f<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 floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1282 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1283 (double).</dd>
1284
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1285 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1286 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1287 <i>size</i>.</dd>
1288
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1289 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1290 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1291 <i>size</i>.</dd>
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1292
1293 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1294 <dd>This specifies a set of native integer widths for the target CPU
1295 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1296 "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]1297 this set are considered to support most general arithmetic
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1298 operations efficiently.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1299</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1300
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1301<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1302 default set of specifications which are then (possibly) overriden by the
1303 specifications in the <tt>datalayout</tt> keyword. The default specifications
1304 are given in this list:</p>
1305
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1306<ul>
1307 <li><tt>E</tt> - big endian</li>
Dan Gohmane78194f2010-02-23 02:44:03 +0000[diff] [blame]1308 <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]1309 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1310 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1311 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1312 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1313 <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]1314 alignment of 64-bits</li>
1315 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1316 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1317 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1318 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1319 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1320 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1321</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1322
1323<p>When LLVM is determining the alignment for a given type, it uses the
1324 following rules:</p>
1325
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1326<ol>
1327 <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]1328 specification is used.</li>
1329
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1330 <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]1331 smallest integer type that is larger than the bitwidth of the sought type
1332 is used. If none of the specifications are larger than the bitwidth then
1333 the the largest integer type is used. For example, given the default
1334 specifications above, the i7 type will use the alignment of i8 (next
1335 largest) while both i65 and i256 will use the alignment of i64 (largest
1336 specified).</li>
1337
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1338 <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]1339 largest vector type that is smaller than the sought vector type will be
1340 used as a fall back. This happens because &lt;128 x double&gt; can be
1341 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1342</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1343
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1344</div>
1345
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1346<!-- ======================================================================= -->
1347<div class="doc_subsection">
1348 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1349</div>
1350
1351<div class="doc_text">
1352
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1353<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1354with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1355is undefined. Pointer values are associated with address ranges
1356according to the following rules:</p>
1357
1358<ul>
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1359 <li>A pointer value formed from a
1360 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1361 is associated with the addresses associated with the first operand
1362 of the <tt>getelementptr</tt>.</li>
1363 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1364 range of the variable's storage.</li>
1365 <li>The result value of an allocation instruction is associated with
1366 the address range of the allocated storage.</li>
1367 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1368 no address.</li>
1369 <li>A pointer value formed by an
1370 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1371 address ranges of all pointer values that contribute (directly or
1372 indirectly) to the computation of the pointer's value.</li>
1373 <li>The result value of a
1374 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1375 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1376 <li>An integer constant other than zero or a pointer value returned
1377 from a function not defined within LLVM may be associated with address
1378 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1379 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1380 allocated by mechanisms provided by LLVM.</li>
1381 </ul>
1382
1383<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1384<tt><a href="#i_load">load</a></tt> merely indicates the size and
1385alignment of the memory from which to load, as well as the
1386interpretation of the value. The first operand of a
1387<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1388and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1389
1390<p>Consequently, type-based alias analysis, aka TBAA, aka
1391<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1392LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1393additional information which specialized optimization passes may use
1394to implement type-based alias analysis.</p>
1395
1396</div>
1397
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]1398<!-- ======================================================================= -->
1399<div class="doc_subsection">
1400 <a name="volatile">Volatile Memory Accesses</a>
1401</div>
1402
1403<div class="doc_text">
1404
1405<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1406href="#i_store"><tt>store</tt></a>s, and <a
1407href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1408The optimizers must not change the number of volatile operations or change their
1409order of execution relative to other volatile operations. The optimizers
1410<i>may</i> change the order of volatile operations relative to non-volatile
1411operations. This is not Java's "volatile" and has no cross-thread
1412synchronization behavior.</p>
1413
1414</div>
1415
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1416<!-- *********************************************************************** -->
1417<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1418<!-- *********************************************************************** -->
1419
1420<div class="doc_text">
1421
1422<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1423 intermediate representation. Being typed enables a number of optimizations
1424 to be performed on the intermediate representation directly, without having
1425 to do extra analyses on the side before the transformation. A strong type
1426 system makes it easier to read the generated code and enables novel analyses
1427 and transformations that are not feasible to perform on normal three address
1428 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1429
1430</div>
1431
1432<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1433<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1434Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1435
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1436<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1437
1438<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1439
1440<table border="1" cellspacing="0" cellpadding="4">
1441 <tbody>
1442 <tr><th>Classification</th><th>Types</th></tr>
1443 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1444 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1445 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1446 </tr>
1447 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1448 <td><a href="#t_floating">floating point</a></td>
1449 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1450 </tr>
1451 <tr>
1452 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1453 <td><a href="#t_integer">integer</a>,
1454 <a href="#t_floating">floating point</a>,
1455 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1456 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1457 <a href="#t_struct">structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1458 <a href="#t_union">union</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1459 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1460 <a href="#t_label">label</a>,
1461 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1462 </td>
1463 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1464 <tr>
1465 <td><a href="#t_primitive">primitive</a></td>
1466 <td><a href="#t_label">label</a>,
1467 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1468 <a href="#t_floating">floating point</a>,
1469 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1470 </tr>
1471 <tr>
1472 <td><a href="#t_derived">derived</a></td>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1473 <td><a href="#t_array">array</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1474 <a href="#t_function">function</a>,
1475 <a href="#t_pointer">pointer</a>,
1476 <a href="#t_struct">structure</a>,
1477 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1478 <a href="#t_union">union</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1479 <a href="#t_vector">vector</a>,
1480 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1481 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1482 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1483 </tbody>
1484</table>
1485
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1486<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1487 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1488 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1489
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1490</div>
1491
1492<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1493<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1494
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1495<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1496
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1497<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1498 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1499
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1500</div>
1501
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1502<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1503<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1504
1505<div class="doc_text">
1506
1507<h5>Overview:</h5>
1508<p>The integer type is a very simple type that simply specifies an arbitrary
1509 bit width for the integer type desired. Any bit width from 1 bit to
1510 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1511
1512<h5>Syntax:</h5>
1513<pre>
1514 iN
1515</pre>
1516
1517<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1518 value.</p>
1519
1520<h5>Examples:</h5>
1521<table class="layout">
1522 <tr class="layout">
1523 <td class="left"><tt>i1</tt></td>
1524 <td class="left">a single-bit integer.</td>
1525 </tr>
1526 <tr class="layout">
1527 <td class="left"><tt>i32</tt></td>
1528 <td class="left">a 32-bit integer.</td>
1529 </tr>
1530 <tr class="layout">
1531 <td class="left"><tt>i1942652</tt></td>
1532 <td class="left">a really big integer of over 1 million bits.</td>
1533 </tr>
1534</table>
1535
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1536</div>
1537
1538<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1539<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1540
1541<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1542
1543<table>
1544 <tbody>
1545 <tr><th>Type</th><th>Description</th></tr>
1546 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1547 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1548 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1549 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1550 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1551 </tbody>
1552</table>
1553
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1554</div>
1555
1556<!-- _______________________________________________________________________ -->
1557<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1558
1559<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1560
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1561<h5>Overview:</h5>
1562<p>The void type does not represent any value and has no size.</p>
1563
1564<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1565<pre>
1566 void
1567</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1568
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1569</div>
1570
1571<!-- _______________________________________________________________________ -->
1572<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1573
1574<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1575
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1576<h5>Overview:</h5>
1577<p>The label type represents code labels.</p>
1578
1579<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1580<pre>
1581 label
1582</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1583
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1584</div>
1585
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1586<!-- _______________________________________________________________________ -->
1587<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1588
1589<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1590
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1591<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1592<p>The metadata type represents embedded metadata. No derived types may be
1593 created from metadata except for <a href="#t_function">function</a>
1594 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1595
1596<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1597<pre>
1598 metadata
1599</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1600
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1601</div>
1602
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1603
1604<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1605<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1606
1607<div class="doc_text">
1608
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1609<p>The real power in LLVM comes from the derived types in the system. This is
1610 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1611 useful types. Each of these types contain one or more element types which
1612 may be a primitive type, or another derived type. For example, it is
1613 possible to have a two dimensional array, using an array as the element type
1614 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1615
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1616
1617</div>
1618
1619<!-- _______________________________________________________________________ -->
1620<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1621
1622<div class="doc_text">
1623
1624<p>Aggregate Types are a subset of derived types that can contain multiple
1625 member types. <a href="#t_array">Arrays</a>,
1626 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1627 <a href="#t_union">unions</a> are aggregate types.</p>
1628
1629</div>
1630
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1631</div>
1632
1633<!-- _______________________________________________________________________ -->
1634<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1635
1636<div class="doc_text">
1637
1638<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1639<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1640 sequentially in memory. The array type requires a size (number of elements)
1641 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1642
1643<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1644<pre>
1645 [&lt;# elements&gt; x &lt;elementtype&gt;]
1646</pre>
1647
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1648<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1649 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1650
1651<h5>Examples:</h5>
1652<table class="layout">
1653 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1654 <td class="left"><tt>[40 x i32]</tt></td>
1655 <td class="left">Array of 40 32-bit integer values.</td>
1656 </tr>
1657 <tr class="layout">
1658 <td class="left"><tt>[41 x i32]</tt></td>
1659 <td class="left">Array of 41 32-bit integer values.</td>
1660 </tr>
1661 <tr class="layout">
1662 <td class="left"><tt>[4 x i8]</tt></td>
1663 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1664 </tr>
1665</table>
1666<p>Here are some examples of multidimensional arrays:</p>
1667<table class="layout">
1668 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1669 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1670 <td class="left">3x4 array of 32-bit integer values.</td>
1671 </tr>
1672 <tr class="layout">
1673 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1674 <td class="left">12x10 array of single precision floating point values.</td>
1675 </tr>
1676 <tr class="layout">
1677 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1678 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1679 </tr>
1680</table>
1681
Dan Gohman87ec5ad2009-11-09 19:01:53 +0000[diff] [blame]1682<p>There is no restriction on indexing beyond the end of the array implied by
1683 a static type (though there are restrictions on indexing beyond the bounds
1684 of an allocated object in some cases). This means that single-dimension
1685 'variable sized array' addressing can be implemented in LLVM with a zero
1686 length array type. An implementation of 'pascal style arrays' in LLVM could
1687 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1688
1689</div>
1690
1691<!-- _______________________________________________________________________ -->
1692<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1693
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1694<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1695
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1696<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1697<p>The function type can be thought of as a function signature. It consists of
1698 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]1699 function type is a scalar type, a void type, a struct type, or a union
1700 type. If the return type is a struct type then all struct elements must be
1701 of first class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1702
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1703<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1704<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1705 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1706</pre>
1707
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1708<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]1709 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1710 which indicates that the function takes a variable number of arguments.
1711 Variable argument functions can access their arguments with
1712 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1713 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1714 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1715
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1716<h5>Examples:</h5>
1717<table class="layout">
1718 <tr class="layout">
1719 <td class="left"><tt>i32 (i32)</tt></td>
1720 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1721 </td>
1722 </tr><tr class="layout">
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1723 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1724 </tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1725 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1726 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1727 returning <tt>float</tt>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1728 </td>
1729 </tr><tr class="layout">
1730 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1731 <td class="left">A vararg function that takes at least one
1732 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1733 which returns an integer. This is the signature for <tt>printf</tt> in
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1734 LLVM.
1735 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1736 </tr><tr class="layout">
1737 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1738 <td class="left">A function taking an <tt>i32</tt>, returning a
1739 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1740 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1741 </tr>
1742</table>
1743
1744</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1745
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1746<!-- _______________________________________________________________________ -->
1747<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1748
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1749<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1750
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1751<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1752<p>The structure type is used to represent a collection of data members together
1753 in memory. The packing of the field types is defined to match the ABI of the
1754 underlying processor. The elements of a structure may be any type that has a
1755 size.</p>
1756
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]1757<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1758 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1759 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1760 Structures in registers are accessed using the
1761 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1762 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1763<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1764<pre>
1765 { &lt;type list&gt; }
1766</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1767
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1768<h5>Examples:</h5>
1769<table class="layout">
1770 <tr class="layout">
1771 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1772 <td class="left">A triple of three <tt>i32</tt> values</td>
1773 </tr><tr class="layout">
1774 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1775 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1776 second element is a <a href="#t_pointer">pointer</a> to a
1777 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1778 an <tt>i32</tt>.</td>
1779 </tr>
1780</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1781
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1782</div>
1783
1784<!-- _______________________________________________________________________ -->
1785<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1786</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1787
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1788<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1789
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1790<h5>Overview:</h5>
1791<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1792 together in memory. There is no padding between fields. Further, the
1793 alignment of a packed structure is 1 byte. The elements of a packed
1794 structure may be any type that has a size.</p>
1795
1796<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1797 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1798 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1799
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1800<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1801<pre>
1802 &lt; { &lt;type list&gt; } &gt;
1803</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1804
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1805<h5>Examples:</h5>
1806<table class="layout">
1807 <tr class="layout">
1808 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1809 <td class="left">A triple of three <tt>i32</tt> values</td>
1810 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1811 <td class="left">
1812<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1813 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1814 second element is a <a href="#t_pointer">pointer</a> to a
1815 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1816 an <tt>i32</tt>.</td>
1817 </tr>
1818</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1819
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1820</div>
1821
1822<!-- _______________________________________________________________________ -->
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1823<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1824
1825<div class="doc_text">
1826
1827<h5>Overview:</h5>
1828<p>A union type describes an object with size and alignment suitable for
1829 an object of any one of a given set of types (also known as an "untagged"
1830 union). It is similar in concept and usage to a
1831 <a href="#t_struct">struct</a>, except that all members of the union
1832 have an offset of zero. The elements of a union may be any type that has a
1833 size. Unions must have at least one member - empty unions are not allowed.
1834 </p>
1835
1836<p>The size of the union as a whole will be the size of its largest member,
1837 and the alignment requirements of the union as a whole will be the largest
1838 alignment requirement of any member.</p>
1839
Dan Gohmanef8400c2010-02-25 16:51:31 +0000[diff] [blame]1840<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]1841 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1842 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1843 Since all members are at offset zero, the getelementptr instruction does
1844 not affect the address, only the type of the resulting pointer.</p>
1845
1846<h5>Syntax:</h5>
1847<pre>
1848 union { &lt;type list&gt; }
1849</pre>
1850
1851<h5>Examples:</h5>
1852<table class="layout">
1853 <tr class="layout">
1854 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1855 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1856 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1857 </tr><tr class="layout">
1858 <td class="left">
1859 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1860 <td class="left">A union, where the first element is a <tt>float</tt> and the
1861 second element is a <a href="#t_pointer">pointer</a> to a
1862 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1863 an <tt>i32</tt>.</td>
1864 </tr>
1865</table>
1866
1867</div>
1868
1869<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1870<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1871
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1872<div class="doc_text">
1873
1874<h5>Overview:</h5>
Dan Gohmanb2f72c82010-02-25 16:50:07 +0000[diff] [blame]1875<p>The pointer type is used to specify memory locations.
1876 Pointers are commonly used to reference objects in memory.</p>
1877
1878<p>Pointer types may have an optional address space attribute defining the
1879 numbered address space where the pointed-to object resides. The default
1880 address space is number zero. The semantics of non-zero address
1881 spaces are target-specific.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1882
1883<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1884 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1885
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1886<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1887<pre>
1888 &lt;type&gt; *
1889</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1890
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1891<h5>Examples:</h5>
1892<table class="layout">
1893 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1894 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1895 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1896 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1897 </tr>
1898 <tr class="layout">
1899 <td class="left"><tt>i32 (i32 *) *</tt></td>
1900 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1901 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1902 <tt>i32</tt>.</td>
1903 </tr>
1904 <tr class="layout">
1905 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1906 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1907 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1908 </tr>
1909</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1910
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1911</div>
1912
1913<!-- _______________________________________________________________________ -->
1914<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1915
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1916<div class="doc_text">
1917
1918<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1919<p>A vector type is a simple derived type that represents a vector of elements.
1920 Vector types are used when multiple primitive data are operated in parallel
1921 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands87598b02009-11-27 13:38:03 +0000[diff] [blame]1922 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1923 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1924
1925<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1926<pre>
1927 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1928</pre>
1929
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1930<p>The number of elements is a constant integer value; elementtype may be any
1931 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1932
1933<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1934<table class="layout">
1935 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1936 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1937 <td class="left">Vector of 4 32-bit integer values.</td>
1938 </tr>
1939 <tr class="layout">
1940 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1941 <td class="left">Vector of 8 32-bit floating-point values.</td>
1942 </tr>
1943 <tr class="layout">
1944 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1945 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1946 </tr>
1947</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1948
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1949</div>
1950
1951<!-- _______________________________________________________________________ -->
1952<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1953<div class="doc_text">
1954
1955<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1956<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1957 corresponds (for example) to the C notion of a forward declared structure
1958 type. In LLVM, opaque types can eventually be resolved to any type (not just
1959 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1960
1961<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1962<pre>
1963 opaque
1964</pre>
1965
1966<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1967<table class="layout">
1968 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1969 <td class="left"><tt>opaque</tt></td>
1970 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1971 </tr>
1972</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1973
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1974</div>
1975
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1976<!-- ======================================================================= -->
1977<div class="doc_subsection">
1978 <a name="t_uprefs">Type Up-references</a>
1979</div>
1980
1981<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1982
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1983<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1984<p>An "up reference" allows you to refer to a lexically enclosing type without
1985 requiring it to have a name. For instance, a structure declaration may
1986 contain a pointer to any of the types it is lexically a member of. Example
1987 of up references (with their equivalent as named type declarations)
1988 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1989
1990<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1991 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1992 { \2 }* %y = type { %y }*
1993 \1* %z = type %z*
1994</pre>
1995
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1996<p>An up reference is needed by the asmprinter for printing out cyclic types
1997 when there is no declared name for a type in the cycle. Because the
1998 asmprinter does not want to print out an infinite type string, it needs a
1999 syntax to handle recursive types that have no names (all names are optional
2000 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2001
2002<h5>Syntax:</h5>
2003<pre>
2004 \&lt;level&gt;
2005</pre>
2006
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2007<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]2008
2009<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2010<table class="layout">
2011 <tr class="layout">
2012 <td class="left"><tt>\1*</tt></td>
2013 <td class="left">Self-referential pointer.</td>
2014 </tr>
2015 <tr class="layout">
2016 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2017 <td class="left">Recursive structure where the upref refers to the out-most
2018 structure.</td>
2019 </tr>
2020</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2021
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2022</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2023
2024<!-- *********************************************************************** -->
2025<div class="doc_section"> <a name="constants">Constants</a> </div>
2026<!-- *********************************************************************** -->
2027
2028<div class="doc_text">
2029
2030<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2031 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2032
2033</div>
2034
2035<!-- ======================================================================= -->
2036<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
2037
2038<div class="doc_text">
2039
2040<dl>
2041 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2042 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]2043 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2044
2045 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2046 <dd>Standard integers (such as '4') are constants of
2047 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2048 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2049
2050 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2051 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2052 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2053 notation (see below). The assembler requires the exact decimal value of a
2054 floating-point constant. For example, the assembler accepts 1.25 but
2055 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2056 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2057
2058 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2059 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2060 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2061</dl>
2062
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2063<p>The one non-intuitive notation for constants is the hexadecimal form of
2064 floating point constants. For example, the form '<tt>double
2065 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2066 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2067 constants are required (and the only time that they are generated by the
2068 disassembler) is when a floating point constant must be emitted but it cannot
2069 be represented as a decimal floating point number in a reasonable number of
2070 digits. For example, NaN's, infinities, and other special values are
2071 represented in their IEEE hexadecimal format so that assembly and disassembly
2072 do not cause any bits to change in the constants.</p>
2073
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]2074<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2075 represented using the 16-digit form shown above (which matches the IEEE754
2076 representation for double); float values must, however, be exactly
2077 representable as IEE754 single precision. Hexadecimal format is always used
2078 for long double, and there are three forms of long double. The 80-bit format
2079 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2080 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2081 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2082 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2083 currently supported target uses this format. Long doubles will only work if
2084 they match the long double format on your target. All hexadecimal formats
2085 are big-endian (sign bit at the left).</p>
2086
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2087</div>
2088
2089<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2090<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2091<a name="aggregateconstants"></a> <!-- old anchor -->
2092<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2093</div>
2094
2095<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2096
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2097<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2098 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2099
2100<dl>
2101 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2102 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2103 type definitions (a comma separated list of elements, surrounded by braces
2104 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2105 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2106 Structure constants must have <a href="#t_struct">structure type</a>, and
2107 the number and types of elements must match those specified by the
2108 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2109
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2110 <dt><b>Union constants</b></dt>
2111 <dd>Union constants are represented with notation similar to a structure with
2112 a single element - that is, a single typed element surrounded
2113 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2114 <a href="#t_union">union type</a> can be initialized with a single-element
2115 struct as long as the type of the struct element matches the type of
2116 one of the union members.</dd>
2117
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2118 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2119 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2120 definitions (a comma separated list of elements, surrounded by square
2121 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2122 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2123 the number and types of elements must match those specified by the
2124 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2125
2126 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2127 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2128 definitions (a comma separated list of elements, surrounded by
2129 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2130 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2131 have <a href="#t_vector">vector type</a>, and the number and types of
2132 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2133
2134 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2135 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2136 value to zero of <em>any</em> type, including scalar and
2137 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2138 This is often used to avoid having to print large zero initializers
2139 (e.g. for large arrays) and is always exactly equivalent to using explicit
2140 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2141
2142 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]2143 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2144 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2145 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2146 be interpreted as part of the instruction stream, metadata is a place to
2147 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2148</dl>
2149
2150</div>
2151
2152<!-- ======================================================================= -->
2153<div class="doc_subsection">
2154 <a name="globalconstants">Global Variable and Function Addresses</a>
2155</div>
2156
2157<div class="doc_text">
2158
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2159<p>The addresses of <a href="#globalvars">global variables</a>
2160 and <a href="#functionstructure">functions</a> are always implicitly valid
2161 (link-time) constants. These constants are explicitly referenced when
2162 the <a href="#identifiers">identifier for the global</a> is used and always
2163 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2164 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2165
2166<div class="doc_code">
2167<pre>
2168@X = global i32 17
2169@Y = global i32 42
2170@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2171</pre>
2172</div>
2173
2174</div>
2175
2176<!-- ======================================================================= -->
2177<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2178<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2179
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2180<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]2181 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2182 Undefined values may be of any type (other than label or void) and be used
2183 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2184
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2185<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2186 program is well defined no matter what value is used. This gives the
2187 compiler more freedom to optimize. Here are some examples of (potentially
2188 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2189
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2190
2191<div class="doc_code">
2192<pre>
2193 %A = add %X, undef
2194 %B = sub %X, undef
2195 %C = xor %X, undef
2196Safe:
2197 %A = undef
2198 %B = undef
2199 %C = undef
2200</pre>
2201</div>
2202
2203<p>This is safe because all of the output bits are affected by the undef bits.
2204Any output bit can have a zero or one depending on the input bits.</p>
2205
2206<div class="doc_code">
2207<pre>
2208 %A = or %X, undef
2209 %B = and %X, undef
2210Safe:
2211 %A = -1
2212 %B = 0
2213Unsafe:
2214 %A = undef
2215 %B = undef
2216</pre>
2217</div>
2218
2219<p>These logical operations have bits that are not always affected by the input.
2220For example, if "%X" has a zero bit, then the output of the 'and' operation will
2221always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2222such, 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]2223However, it is safe to assume that all bits of the undef could be 0, and
2224optimize the and to 0. Likewise, it is safe to assume that all the bits of
2225the 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]2226-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2227
2228<div class="doc_code">
2229<pre>
2230 %A = select undef, %X, %Y
2231 %B = select undef, 42, %Y
2232 %C = select %X, %Y, undef
2233Safe:
2234 %A = %X (or %Y)
2235 %B = 42 (or %Y)
2236 %C = %Y
2237Unsafe:
2238 %A = undef
2239 %B = undef
2240 %C = undef
2241</pre>
2242</div>
2243
2244<p>This set of examples show that undefined select (and conditional branch)
2245conditions can go "either way" but they have to come from one of the two
2246operands. In the %A example, if %X and %Y were both known to have a clear low
2247bit, then %A would have to have a cleared low bit. However, in the %C example,
2248the optimizer is allowed to assume that the undef operand could be the same as
2249%Y, allowing the whole select to be eliminated.</p>
2250
2251
2252<div class="doc_code">
2253<pre>
2254 %A = xor undef, undef
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2255
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2256 %B = undef
2257 %C = xor %B, %B
2258
2259 %D = undef
2260 %E = icmp lt %D, 4
2261 %F = icmp gte %D, 4
2262
2263Safe:
2264 %A = undef
2265 %B = undef
2266 %C = undef
2267 %D = undef
2268 %E = undef
2269 %F = undef
2270</pre>
2271</div>
2272
2273<p>This example points out that two undef operands are not necessarily the same.
2274This can be surprising to people (and also matches C semantics) where they
2275assume that "X^X" is always zero, even if X is undef. This isn't true for a
2276number of reasons, but the short answer is that an undef "variable" can
2277arbitrarily change its value over its "live range". This is true because the
2278"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2279logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2280so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2281to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2282would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2283
2284<div class="doc_code">
2285<pre>
2286 %A = fdiv undef, %X
2287 %B = fdiv %X, undef
2288Safe:
2289 %A = undef
2290b: unreachable
2291</pre>
2292</div>
2293
2294<p>These examples show the crucial difference between an <em>undefined
2295value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2296allowed to have an arbitrary bit-pattern. This means that the %A operation
2297can be constant folded to undef because the undef could be an SNaN, and fdiv is
2298not (currently) defined on SNaN's. However, in the second example, we can make
2299a more aggressive assumption: because the undef is allowed to be an arbitrary
2300value, 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]2301has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2302does not execute at all. This allows us to delete the divide and all code after
2303it: since the undefined operation "can't happen", the optimizer can assume that
2304it occurs in dead code.
2305</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2306
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2307<div class="doc_code">
2308<pre>
2309a: store undef -> %X
2310b: store %X -> undef
2311Safe:
2312a: &lt;deleted&gt;
2313b: unreachable
2314</pre>
2315</div>
2316
2317<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2318can be assumed to not have any effect: we can assume that the value is
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2319overwritten with bits that happen to match what was already there. However, a
2320store "to" an undefined location could clobber arbitrary memory, therefore, it
2321has undefined behavior.</p>
2322
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2323</div>
2324
2325<!-- ======================================================================= -->
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2326<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2327<div class="doc_text">
2328
Dan Gohman67bf37f2010-04-26 20:21:21 +0000[diff] [blame]2329<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2330 instead of representing an unspecified bit pattern, they represent the
2331 fact that an instruction or constant expression which cannot evoke side
2332 effects has nevertheless detected a condition which results in undefined
Dan Gohman67bf37f2010-04-26 20:21:21 +0000[diff] [blame]2333 behavior.</p>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2334
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame^]2335<p>Any value other than a non-intrinsic call, invoke, or phi with a trap
2336 operand has trap as its result value. Any instruction with
2337 a trap operand which may have side effects emits those side effects as
2338 if it had an undef operand instead. If the side effects are externally
2339 visible, the behavior is undefined.</p>
2340
2341<p>Trap values may be stored to memory; a load from memory including any
2342 part of a trap value results in a (full) trap value.</p>
2343
2344<p>For example:</p>
2345
2346<!-- FIXME: In the case of multiple threads, this only applies to loads from
2347 the same thread as the store, or loads which are sequenced after the
2348 store by synchronization. -->
2349
2350<div class="doc_code">
2351<pre>
2352%trap = sub nuw i32 0, 1 ; Results in a trap value.
2353%still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2354%trap_yet_again = getelementptr i32* @h, i32 %still_trap
2355store i32 0, i32* %trap_yet_again ; undefined behavior
2356
2357volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2358%trap2 = load i32* @g ; Returns a trap value, not just undef.
2359%narrowaddr = bitcast i32* @g to i16*
2360%wideaddr = bitcast i32* @g to i64*
2361%trap3 = load 16* %narrowaddr ; Returns a trap value
2362%trap4 = load i64* %widaddr ; Returns a trap value, not partial trap.
2363</pre>
2364</div>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2365
Dan Gohman54884272010-04-26 20:54:53 +0000[diff] [blame]2366<p>If a <a href="#i_br"><tt>br</tt></a> or
2367 <a href="#i_switch"><tt>switch</tt></a> instruction has a trap value
2368 operand, all non-phi non-void instructions which control-depend on it
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame^]2369 have trap as their result value. A <a href="#i_phi"><tt>phi</tt></a>
2370 node with an incoming value associated with a control edge which is
2371 control-dependent on it has trap as its result value when control is
2372 transferred from that block. If any instruction which control-depends
2373 on the <tt>br</tt> or <tt>switch</tt> invokes externally visible side
2374 effects, the behavior of the program is undefined. For example:</p>
Dan Gohman54884272010-04-26 20:54:53 +0000[diff] [blame]2375
2376<!-- FIXME: What about exceptions thrown from control-dependent instrs? -->
2377
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame^]2378<div class="doc_code">
2379<pre>
2380entry:
2381 %trap = sub nuw i32 0, 1 ; Results in a trap value.
2382 %cmp = icmp i32 slt %trap, 0 ; Still trap.
2383 %br i1 %cmp, %true, %end ; Branch to either destination.
2384
2385true:
2386 volatile store i32 0, i32* @g ; Externally visible side effects
2387 ; control-dependent on %cmp.
2388 ; Undefined behavior.
2389 br label %end
2390
2391end:
2392 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2393 ; Both edges into this PHI are
2394 ; control-dependent on %cmp, so this
2395 ; results in a trap value.
2396
2397 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2398 ; so this is defined (ignoring earlier
2399 ; undefined behavior in this example).
2400
2401</pre>
2402</div>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2403
2404<p>There is currently no way of representing a trap constant in the IR; they
2405 only exist when produced by certain instructions, such as an
2406 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag
2407 set, when overflow occurs.</p>
2408
2409</div>
2410
2411<!-- ======================================================================= -->
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2412<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2413 Blocks</a></div>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2414<div class="doc_text">
2415
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2416<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2417
2418<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner24f2e852009-10-27 21:49:40 +0000[diff] [blame]2419 basic block in the specified function, and always has an i8* type. Taking
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2420 the address of the entry block is illegal.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2421
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2422<p>This value only has defined behavior when used as an operand to the
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2423 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2424 against null. Pointer equality tests between labels addresses is undefined
2425 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2426 equal to the null pointer. This may also be passed around as an opaque
2427 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner0bae7b32009-10-27 21:44:20 +0000[diff] [blame]2428 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2429 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2430
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2431<p>Finally, some targets may provide defined semantics when
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2432 using the value as the operand to an inline assembly, but that is target
2433 specific.
2434 </p>
2435
2436</div>
2437
2438
2439<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2440<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2441</div>
2442
2443<div class="doc_text">
2444
2445<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2446 to be used as constants. Constant expressions may be of
2447 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2448 operation that does not have side effects (e.g. load and call are not
2449 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2450
2451<dl>
2452 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2453 <dd>Truncate a constant to another type. The bit size of CST must be larger
2454 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2455
2456 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2457 <dd>Zero extend a constant to another type. The bit size of CST must be
2458 smaller or equal to the bit size of TYPE. Both types must be
2459 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2460
2461 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2462 <dd>Sign extend a constant to another type. The bit size of CST must be
2463 smaller or equal to the bit size of TYPE. Both types must be
2464 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2465
2466 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2467 <dd>Truncate a floating point constant to another floating point type. The
2468 size of CST must be larger than the size of TYPE. Both types must be
2469 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2470
2471 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2472 <dd>Floating point extend a constant to another type. The size of CST must be
2473 smaller or equal to the size of TYPE. Both types must be floating
2474 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2475
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2476 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2477 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2478 constant. TYPE must be a scalar or vector integer type. CST must be of
2479 scalar or vector floating point type. Both CST and TYPE must be scalars,
2480 or vectors of the same number of elements. If the value won't fit in the
2481 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2482
2483 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2484 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2485 constant. TYPE must be a scalar or vector integer type. CST must be of
2486 scalar or vector floating point type. Both CST and TYPE must be scalars,
2487 or vectors of the same number of elements. If the value won't fit in the
2488 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2489
2490 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2491 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2492 constant. TYPE must be a scalar or vector floating point type. CST must be
2493 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2494 vectors of the same number of elements. If the value won't fit in the
2495 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2496
2497 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2498 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2499 constant. TYPE must be a scalar or vector floating point type. CST must be
2500 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2501 vectors of the same number of elements. If the value won't fit in the
2502 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2503
2504 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2505 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2506 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2507 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2508 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2509
2510 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2511 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2512 type. CST must be of integer type. The CST value is zero extended,
2513 truncated, or unchanged to make it fit in a pointer size. This one is
2514 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2515
2516 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2517 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2518 are the same as those for the <a href="#i_bitcast">bitcast
2519 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2520
2521 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2522 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2523 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2524 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2525 instruction, the index list may have zero or more indexes, which are
2526 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2527
2528 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2529 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2530
2531 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2532 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2533
2534 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2535 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2536
2537 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2538 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2539 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2540
2541 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2542 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2543 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2544
2545 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2546 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2547 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2548
2549 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2550 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2551 be any of the <a href="#binaryops">binary</a>
2552 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2553 on operands are the same as those for the corresponding instruction
2554 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2555</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2556
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2557</div>
2558
2559<!-- *********************************************************************** -->
2560<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2561<!-- *********************************************************************** -->
2562
2563<!-- ======================================================================= -->
2564<div class="doc_subsection">
2565<a name="inlineasm">Inline Assembler Expressions</a>
2566</div>
2567
2568<div class="doc_text">
2569
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2570<p>LLVM supports inline assembler expressions (as opposed
2571 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2572 a special value. This value represents the inline assembler as a string
2573 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2574 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2575 expression has side effects, and a flag indicating whether the function
2576 containing the asm needs to align its stack conservatively. An example
2577 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2578
2579<div class="doc_code">
2580<pre>
2581i32 (i32) asm "bswap $0", "=r,r"
2582</pre>
2583</div>
2584
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2585<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2586 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2587 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2588
2589<div class="doc_code">
2590<pre>
2591%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2592</pre>
2593</div>
2594
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2595<p>Inline asms with side effects not visible in the constraint list must be
2596 marked as having side effects. This is done through the use of the
2597 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2598
2599<div class="doc_code">
2600<pre>
2601call void asm sideeffect "eieio", ""()
2602</pre>
2603</div>
2604
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2605<p>In some cases inline asms will contain code that will not work unless the
2606 stack is aligned in some way, such as calls or SSE instructions on x86,
2607 yet will not contain code that does that alignment within the asm.
2608 The compiler should make conservative assumptions about what the asm might
2609 contain and should generate its usual stack alignment code in the prologue
2610 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2611
2612<div class="doc_code">
2613<pre>
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2614call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2615</pre>
2616</div>
2617
2618<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2619 first.</p>
2620
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2621<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2622 documented here. Constraints on what can be done (e.g. duplication, moving,
2623 etc need to be documented). This is probably best done by reference to
2624 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnerbafc8372010-04-07 05:38:05 +0000[diff] [blame]2625</div>
2626
2627<div class="doc_subsubsection">
2628<a name="inlineasm_md">Inline Asm Metadata</a>
2629</div>
2630
2631<div class="doc_text">
2632
2633<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2634 attached to it that contains a constant integer. If present, the code
2635 generator will use the integer as the location cookie value when report
2636 errors through the LLVMContext error reporting mechanisms. This allows a
2637 front-end to corrolate backend errors that occur with inline asm back to the
2638 source code that produced it. For example:</p>
2639
2640<div class="doc_code">
2641<pre>
2642call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2643...
2644!42 = !{ i32 1234567 }
2645</pre>
2646</div>
2647
2648<p>It is up to the front-end to make sense of the magic numbers it places in the
2649 IR.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2650
2651</div>
2652
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2653<!-- ======================================================================= -->
2654<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2655 Strings</a>
2656</div>
2657
2658<div class="doc_text">
2659
2660<p>LLVM IR allows metadata to be attached to instructions in the program that
2661 can convey extra information about the code to the optimizers and code
2662 generator. One example application of metadata is source-level debug
2663 information. There are two metadata primitives: strings and nodes. All
2664 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2665 preceding exclamation point ('<tt>!</tt>').</p>
2666
2667<p>A metadata string is a string surrounded by double quotes. It can contain
2668 any character by escaping non-printable characters with "\xx" where "xx" is
2669 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2670
2671<p>Metadata nodes are represented with notation similar to structure constants
2672 (a comma separated list of elements, surrounded by braces and preceded by an
2673 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2674 10}</tt>". Metadata nodes can have any values as their operand.</p>
2675
2676<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2677 metadata nodes, which can be looked up in the module symbol table. For
2678 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2679
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2680<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2681 function is using two metadata arguments.
2682
2683 <div class="doc_code">
2684 <pre>
2685 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2686 </pre>
2687 </div></p>
2688
2689<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2690 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2691
2692 <div class="doc_code">
2693 <pre>
2694 %indvar.next = add i64 %indvar, 1, !dbg !21
2695 </pre>
2696 </div></p>
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2697</div>
2698
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2699
2700<!-- *********************************************************************** -->
2701<div class="doc_section">
2702 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2703</div>
2704<!-- *********************************************************************** -->
2705
2706<p>LLVM has a number of "magic" global variables that contain data that affect
2707code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2708of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2709section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2710by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2711
2712<!-- ======================================================================= -->
2713<div class="doc_subsection">
2714<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2715</div>
2716
2717<div class="doc_text">
2718
2719<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2720href="#linkage_appending">appending linkage</a>. This array contains a list of
2721pointers to global variables and functions which may optionally have a pointer
2722cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2723
2724<pre>
2725 @X = global i8 4
2726 @Y = global i32 123
2727
2728 @llvm.used = appending global [2 x i8*] [
2729 i8* @X,
2730 i8* bitcast (i32* @Y to i8*)
2731 ], section "llvm.metadata"
2732</pre>
2733
2734<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2735compiler, assembler, and linker are required to treat the symbol as if there is
2736a reference to the global that it cannot see. For example, if a variable has
2737internal linkage and no references other than that from the <tt>@llvm.used</tt>
2738list, it cannot be deleted. This is commonly used to represent references from
2739inline asms and other things the compiler cannot "see", and corresponds to
2740"attribute((used))" in GNU C.</p>
2741
2742<p>On some targets, the code generator must emit a directive to the assembler or
2743object file to prevent the assembler and linker from molesting the symbol.</p>
2744
2745</div>
2746
2747<!-- ======================================================================= -->
2748<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2749<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2750</div>
2751
2752<div class="doc_text">
2753
2754<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2755<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2756touching the symbol. On targets that support it, this allows an intelligent
2757linker to optimize references to the symbol without being impeded as it would be
2758by <tt>@llvm.used</tt>.</p>
2759
2760<p>This is a rare construct that should only be used in rare circumstances, and
2761should not be exposed to source languages.</p>
2762
2763</div>
2764
2765<!-- ======================================================================= -->
2766<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2767<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2768</div>
2769
2770<div class="doc_text">
2771
2772<p>TODO: Describe this.</p>
2773
2774</div>
2775
2776<!-- ======================================================================= -->
2777<div class="doc_subsection">
2778<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2779</div>
2780
2781<div class="doc_text">
2782
2783<p>TODO: Describe this.</p>
2784
2785</div>
2786
2787
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2788<!-- *********************************************************************** -->
2789<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2790<!-- *********************************************************************** -->
2791
2792<div class="doc_text">
2793
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2794<p>The LLVM instruction set consists of several different classifications of
2795 instructions: <a href="#terminators">terminator
2796 instructions</a>, <a href="#binaryops">binary instructions</a>,
2797 <a href="#bitwiseops">bitwise binary instructions</a>,
2798 <a href="#memoryops">memory instructions</a>, and
2799 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2800
2801</div>
2802
2803<!-- ======================================================================= -->
2804<div class="doc_subsection"> <a name="terminators">Terminator
2805Instructions</a> </div>
2806
2807<div class="doc_text">
2808
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2809<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2810 in a program ends with a "Terminator" instruction, which indicates which
2811 block should be executed after the current block is finished. These
2812 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2813 control flow, not values (the one exception being the
2814 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2815
Duncan Sands048d8062010-04-15 20:35:54 +0000[diff] [blame]2816<p>There are seven different terminator instructions: the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2817 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2818 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2819 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendlingb4ae2292009-11-02 00:25:26 +0000[diff] [blame]2820 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2821 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2822 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2823 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2824
2825</div>
2826
2827<!-- _______________________________________________________________________ -->
2828<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2829Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2830
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2831<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2832
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2833<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2834<pre>
2835 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]2836 ret void <i>; Return from void function</i>
2837</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2838
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2839<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2840<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2841 a value) from a function back to the caller.</p>
2842
2843<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2844 value and then causes control flow, and one that just causes control flow to
2845 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2846
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2847<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2848<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2849 return value. The type of the return value must be a
2850 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2851
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2852<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2853 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2854 value or a return value with a type that does not match its type, or if it
2855 has a void return type and contains a '<tt>ret</tt>' instruction with a
2856 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2857
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2858<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2859<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2860 the calling function's context. If the caller is a
2861 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2862 instruction after the call. If the caller was an
2863 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2864 the beginning of the "normal" destination block. If the instruction returns
2865 a value, that value shall set the call or invoke instruction's return
2866 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2867
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2868<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2869<pre>
2870 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2871 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2872 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]2873</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2874
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2875</div>
2876<!-- _______________________________________________________________________ -->
2877<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2878
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2879<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2880
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2881<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2882<pre>
2883 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]2884</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2885
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2886<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2887<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2888 different basic block in the current function. There are two forms of this
2889 instruction, corresponding to a conditional branch and an unconditional
2890 branch.</p>
2891
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2892<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2893<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2894 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2895 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2896 target.</p>
2897
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2898<h5>Semantics:</h5>
2899<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2900 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2901 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2902 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2903
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2904<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2905<pre>
2906Test:
2907 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2908 br i1 %cond, label %IfEqual, label %IfUnequal
2909IfEqual:
2910 <a href="#i_ret">ret</a> i32 1
2911IfUnequal:
2912 <a href="#i_ret">ret</a> i32 0
2913</pre>
2914
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2915</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2916
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2917<!-- _______________________________________________________________________ -->
2918<div class="doc_subsubsection">
2919 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2920</div>
2921
2922<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2923
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2924<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2925<pre>
2926 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2927</pre>
2928
2929<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2930<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]2931 several different places. It is a generalization of the '<tt>br</tt>'
2932 instruction, allowing a branch to occur to one of many possible
2933 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2934
2935<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2936<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2937 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2938 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2939 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2940
2941<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2942<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2943 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2944 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2945 transferred to the corresponding destination; otherwise, control flow is
2946 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2947
2948<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2949<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2950 <tt>switch</tt> instruction, this instruction may be code generated in
2951 different ways. For example, it could be generated as a series of chained
2952 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2953
2954<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2955<pre>
2956 <i>; Emulate a conditional br instruction</i>
2957 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2958 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2959
2960 <i>; Emulate an unconditional br instruction</i>
2961 switch i32 0, label %dest [ ]
2962
2963 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2964 switch i32 %val, label %otherwise [ i32 0, label %onzero
2965 i32 1, label %onone
2966 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2967</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2968
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2969</div>
2970
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2971
2972<!-- _______________________________________________________________________ -->
2973<div class="doc_subsubsection">
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2974 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2975</div>
2976
2977<div class="doc_text">
2978
2979<h5>Syntax:</h5>
2980<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2981 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]2982</pre>
2983
2984<h5>Overview:</h5>
2985
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2986<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2987 within the current function, whose address is specified by
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2988 "<tt>address</tt>". Address must be derived from a <a
2989 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2990
2991<h5>Arguments:</h5>
2992
2993<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2994 rest of the arguments indicate the full set of possible destinations that the
2995 address may point to. Blocks are allowed to occur multiple times in the
2996 destination list, though this isn't particularly useful.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2997
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2998<p>This destination list is required so that dataflow analysis has an accurate
2999 understanding of the CFG.</p>
3000
3001<h5>Semantics:</h5>
3002
3003<p>Control transfers to the block specified in the address argument. All
3004 possible destination blocks must be listed in the label list, otherwise this
3005 instruction has undefined behavior. This implies that jumps to labels
3006 defined in other functions have undefined behavior as well.</p>
3007
3008<h5>Implementation:</h5>
3009
3010<p>This is typically implemented with a jump through a register.</p>
3011
3012<h5>Example:</h5>
3013<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]3014 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3015</pre>
3016
3017</div>
3018
3019
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3020<!-- _______________________________________________________________________ -->
3021<div class="doc_subsubsection">
3022 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3023</div>
3024
3025<div class="doc_text">
3026
3027<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3028<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]3029 &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]3030 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
3031</pre>
3032
3033<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3034<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3035 function, with the possibility of control flow transfer to either the
3036 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3037 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3038 control flow will return to the "normal" label. If the callee (or any
3039 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3040 instruction, control is interrupted and continued at the dynamically nearest
3041 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3042
3043<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3044<p>This instruction requires several arguments:</p>
3045
3046<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3047 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3048 convention</a> the call should use. If none is specified, the call
3049 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]3050
3051 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3052 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3053 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]3054
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3055 <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]3056 function value being invoked. In most cases, this is a direct function
3057 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3058 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3059
3060 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3061 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3062
3063 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]3064 signature argument types and parameter attributes. All arguments must be
3065 of <a href="#t_firstclass">first class</a> type. If the function
3066 signature indicates the function accepts a variable number of arguments,
3067 the extra arguments can be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3068
3069 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3070 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3071
3072 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3073 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3074
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]3075 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3076 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3077 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3078</ol>
3079
3080<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3081<p>This instruction is designed to operate as a standard
3082 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3083 primary difference is that it establishes an association with a label, which
3084 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3085
3086<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3087 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3088 exception. Additionally, this is important for implementation of
3089 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3090
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3091<p>For the purposes of the SSA form, the definition of the value returned by the
3092 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3093 block to the "normal" label. If the callee unwinds then no return value is
3094 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]3095
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]3096<p>Note that the code generator does not yet completely support unwind, and
3097that the invoke/unwind semantics are likely to change in future versions.</p>
3098
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3099<h5>Example:</h5>
3100<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]3101 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3102 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]3103 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3104 unwind label %TestCleanup <i>; {i32}:retval set</i>
3105</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3106
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3107</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3108
3109<!-- _______________________________________________________________________ -->
3110
3111<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3112Instruction</a> </div>
3113
3114<div class="doc_text">
3115
3116<h5>Syntax:</h5>
3117<pre>
3118 unwind
3119</pre>
3120
3121<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3122<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3123 at the first callee in the dynamic call stack which used
3124 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3125 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3126
3127<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3128<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3129 immediately halt. The dynamic call stack is then searched for the
3130 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3131 Once found, execution continues at the "exceptional" destination block
3132 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3133 instruction in the dynamic call chain, undefined behavior results.</p>
3134
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]3135<p>Note that the code generator does not yet completely support unwind, and
3136that the invoke/unwind semantics are likely to change in future versions.</p>
3137
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3138</div>
3139
3140<!-- _______________________________________________________________________ -->
3141
3142<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3143Instruction</a> </div>
3144
3145<div class="doc_text">
3146
3147<h5>Syntax:</h5>
3148<pre>
3149 unreachable
3150</pre>
3151
3152<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3153<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3154 instruction is used to inform the optimizer that a particular portion of the
3155 code is not reachable. This can be used to indicate that the code after a
3156 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3157
3158<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3159<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3160
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3161</div>
3162
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3163<!-- ======================================================================= -->
3164<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3165
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3166<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3167
3168<p>Binary operators are used to do most of the computation in a program. They
3169 require two operands of the same type, execute an operation on them, and
3170 produce a single value. The operands might represent multiple data, as is
3171 the case with the <a href="#t_vector">vector</a> data type. The result value
3172 has the same type as its operands.</p>
3173
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3174<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3175
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3176</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3177
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3178<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3179<div class="doc_subsubsection">
3180 <a name="i_add">'<tt>add</tt>' Instruction</a>
3181</div>
3182
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3183<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3184
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3185<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3186<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3187 &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]3188 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3189 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3190 &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]3191</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3192
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3193<h5>Overview:</h5>
3194<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3195
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3196<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3197<p>The two arguments to the '<tt>add</tt>' instruction must
3198 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3199 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3200
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3201<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3202<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3203
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3204<p>If the sum has unsigned overflow, the result returned is the mathematical
3205 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]3206
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3207<p>Because LLVM integers use a two's complement representation, this instruction
3208 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3209
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3210<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3211 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3212 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3213 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3214 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3215
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3216<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3217<pre>
3218 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3219</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3220
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3221</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3222
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3223<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3224<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3225 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3226</div>
3227
3228<div class="doc_text">
3229
3230<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3231<pre>
3232 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3233</pre>
3234
3235<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3236<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3237
3238<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3239<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3240 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3241 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3242
3243<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3244<p>The value produced is the floating point sum of the two operands.</p>
3245
3246<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3247<pre>
3248 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3249</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3250
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3251</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3252
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3253<!-- _______________________________________________________________________ -->
3254<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3255 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3256</div>
3257
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3258<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3259
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3260<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3261<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3262 &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]3263 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3264 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3265 &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]3266</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3267
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3268<h5>Overview:</h5>
3269<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3270 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3271
3272<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3273 '<tt>neg</tt>' instruction present in most other intermediate
3274 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3275
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3276<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3277<p>The two arguments to the '<tt>sub</tt>' instruction must
3278 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3279 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3280
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3281<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3282<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3283
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3284<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3285 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3286 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3287
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3288<p>Because LLVM integers use a two's complement representation, this instruction
3289 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3290
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3291<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3292 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3293 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3294 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3295 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3296
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3297<h5>Example:</h5>
3298<pre>
3299 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
3300 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
3301</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3302
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3303</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3304
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3305<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3306<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3307 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3308</div>
3309
3310<div class="doc_text">
3311
3312<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3313<pre>
3314 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3315</pre>
3316
3317<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3318<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3319 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3320
3321<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3322 '<tt>fneg</tt>' instruction present in most other intermediate
3323 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3324
3325<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]3326<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3327 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3328 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3329
3330<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3331<p>The value produced is the floating point difference of the two operands.</p>
3332
3333<h5>Example:</h5>
3334<pre>
3335 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3336 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3337</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3338
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3339</div>
3340
3341<!-- _______________________________________________________________________ -->
3342<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3343 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3344</div>
3345
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3346<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3347
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3348<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3349<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3350 &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]3351 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3352 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3353 &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]3354</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3355
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3356<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3357<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3358
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3359<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3360<p>The two arguments to the '<tt>mul</tt>' instruction must
3361 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3362 integer values. Both arguments must have identical types.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3363
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3364<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3365<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3366
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3367<p>If the result of the multiplication has unsigned overflow, the result
3368 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3369 width of the result.</p>
3370
3371<p>Because LLVM integers use a two's complement representation, and the result
3372 is the same width as the operands, this instruction returns the correct
3373 result for both signed and unsigned integers. If a full product
3374 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3375 be sign-extended or zero-extended as appropriate to the width of the full
3376 product.</p>
3377
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3378<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3379 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3380 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3381 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3382 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3383
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3384<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3385<pre>
3386 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3387</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3388
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3389</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3390
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3391<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3392<div class="doc_subsubsection">
3393 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3394</div>
3395
3396<div class="doc_text">
3397
3398<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3399<pre>
3400 &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]3401</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3402
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3403<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3404<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3405
3406<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3407<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3408 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3409 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3410
3411<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3412<p>The value produced is the floating point product of the two operands.</p>
3413
3414<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3415<pre>
3416 &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]3417</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3418
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3419</div>
3420
3421<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3422<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3423</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3424
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3425<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3426
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3427<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3428<pre>
3429 &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]3430</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3431
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3432<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3433<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3434
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3435<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3436<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3437 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3438 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3439
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3440<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3441<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3442
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3443<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3444 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3445
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3446<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3447
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3448<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3449<pre>
3450 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3451</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3452
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3453</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3454
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3455<!-- _______________________________________________________________________ -->
3456<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3457</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3458
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3459<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3460
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3461<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3462<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3463 &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]3464 &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]3465</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3466
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3467<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3468<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3469
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3470<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3471<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3472 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3473 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3474
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3475<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3476<p>The value produced is the signed integer quotient of the two operands rounded
3477 towards zero.</p>
3478
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3479<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3480 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3481
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3482<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3483 undefined behavior; this is a rare case, but can occur, for example, by doing
3484 a 32-bit division of -2147483648 by -1.</p>
3485
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3486<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanf7263862010-04-23 15:23:32 +0000[diff] [blame]3487 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
3488 be rounded or if overflow would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3489
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3490<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3491<pre>
3492 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3493</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3494
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3495</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3496
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3497<!-- _______________________________________________________________________ -->
3498<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3499Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3501<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3502
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3503<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3504<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3505 &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]3506</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3507
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3508<h5>Overview:</h5>
3509<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3510
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3511<h5>Arguments:</h5>
3512<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3513 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3514 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3515
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3516<h5>Semantics:</h5>
3517<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3518
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3519<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3520<pre>
3521 &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]3522</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3524</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3525
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3526<!-- _______________________________________________________________________ -->
3527<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3528</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3530<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3531
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3532<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3533<pre>
3534 &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]3535</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3536
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3537<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3538<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3539 division of its two arguments.</p>
3540
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3541<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3542<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3543 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3544 values. Both arguments must have identical types.</p>
3545
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3546<h5>Semantics:</h5>
3547<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3548 This instruction always performs an unsigned division to get the
3549 remainder.</p>
3550
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3551<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3552 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3553
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3554<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3555
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3556<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3557<pre>
3558 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3559</pre>
3560
3561</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3562
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3563<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3564<div class="doc_subsubsection">
3565 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3566</div>
3567
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3568<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3569
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3570<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3571<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3572 &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]3573</pre>
Chris Lattner6704c212008-05-20 20:48:21 +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>srem</tt>' instruction returns the remainder from the signed
3577 division of its two operands. This instruction can also take
3578 <a href="#t_vector">vector</a> versions of the values in which case the
3579 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3580
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3581<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3582<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3583 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3584 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3585
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3586<h5>Semantics:</h5>
3587<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3588 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3589 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3590 a value. For more information about the difference,
3591 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3592 Math Forum</a>. For a table of how this is implemented in various languages,
3593 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3594 Wikipedia: modulo operation</a>.</p>
3595
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3596<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3597 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3598
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3599<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3600 Overflow also leads to undefined behavior; this is a rare case, but can
3601 occur, for example, by taking the remainder of a 32-bit division of
3602 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3603 lets srem be implemented using instructions that return both the result of
3604 the division and the remainder.)</p>
3605
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3606<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3607<pre>
3608 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3609</pre>
3610
3611</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3612
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3613<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3614<div class="doc_subsubsection">
3615 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3616
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3617<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3618
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3619<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3620<pre>
3621 &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]3622</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3624<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3625<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3626 its two operands.</p>
3627
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3628<h5>Arguments:</h5>
3629<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3630 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3631 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3632
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3633<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3634<p>This instruction returns the <i>remainder</i> of a division. The remainder
3635 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3636
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3637<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3638<pre>
3639 &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]3640</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3641
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3642</div>
3643
3644<!-- ======================================================================= -->
3645<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3646Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3647
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3648<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3649
3650<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3651 program. They are generally very efficient instructions and can commonly be
3652 strength reduced from other instructions. They require two operands of the
3653 same type, execute an operation on them, and produce a single value. The
3654 resulting value is the same type as its operands.</p>
3655
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3656</div>
3657
3658<!-- _______________________________________________________________________ -->
3659<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3660Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3662<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3663
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3664<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3665<pre>
3666 &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]3667</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3668
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3669<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3670<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3671 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3672
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3673<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3674<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3675 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3676 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3677
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3678<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3679<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3680 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3681 is (statically or dynamically) negative or equal to or larger than the number
3682 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3683 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3684 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3685
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3686<h5>Example:</h5>
3687<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3688 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3689 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3690 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3691 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3692 &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]3693</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3694
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3695</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3696
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3697<!-- _______________________________________________________________________ -->
3698<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3699Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3700
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3701<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3702
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3703<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3704<pre>
3705 &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]3706</pre>
3707
3708<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3709<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3710 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3711
3712<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3713<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3714 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3715 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3716
3717<h5>Semantics:</h5>
3718<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3719 significant bits of the result will be filled with zero bits after the shift.
3720 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3721 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3722 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3723 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3724
3725<h5>Example:</h5>
3726<pre>
3727 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3728 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3729 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3730 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3731 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3732 &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]3733</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3734
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3735</div>
3736
3737<!-- _______________________________________________________________________ -->
3738<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3739Instruction</a> </div>
3740<div class="doc_text">
3741
3742<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3743<pre>
3744 &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]3745</pre>
3746
3747<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3748<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3749 operand shifted to the right a specified number of bits with sign
3750 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3751
3752<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3753<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3754 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3755 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3756
3757<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3758<p>This instruction always performs an arithmetic shift right operation, The
3759 most significant bits of the result will be filled with the sign bit
3760 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3761 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3762 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3763 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3764
3765<h5>Example:</h5>
3766<pre>
3767 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3768 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3769 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3770 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3771 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3772 &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]3773</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3774
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3775</div>
3776
3777<!-- _______________________________________________________________________ -->
3778<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3779Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3780
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3781<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3782
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3783<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3784<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3785 &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]3786</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3787
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3788<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3789<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3790 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3792<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3793<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3794 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3795 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3796
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3797<h5>Semantics:</h5>
3798<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3799
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3800<table border="1" cellspacing="0" cellpadding="4">
3801 <tbody>
3802 <tr>
3803 <td>In0</td>
3804 <td>In1</td>
3805 <td>Out</td>
3806 </tr>
3807 <tr>
3808 <td>0</td>
3809 <td>0</td>
3810 <td>0</td>
3811 </tr>
3812 <tr>
3813 <td>0</td>
3814 <td>1</td>
3815 <td>0</td>
3816 </tr>
3817 <tr>
3818 <td>1</td>
3819 <td>0</td>
3820 <td>0</td>
3821 </tr>
3822 <tr>
3823 <td>1</td>
3824 <td>1</td>
3825 <td>1</td>
3826 </tr>
3827 </tbody>
3828</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3829
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3830<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3831<pre>
3832 &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]3833 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3834 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3835</pre>
3836</div>
3837<!-- _______________________________________________________________________ -->
3838<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3839
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3840<div class="doc_text">
3841
3842<h5>Syntax:</h5>
3843<pre>
3844 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3845</pre>
3846
3847<h5>Overview:</h5>
3848<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3849 two operands.</p>
3850
3851<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3852<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3853 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3854 values. Both arguments must have identical types.</p>
3855
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3856<h5>Semantics:</h5>
3857<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3858
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3859<table border="1" cellspacing="0" cellpadding="4">
3860 <tbody>
3861 <tr>
3862 <td>In0</td>
3863 <td>In1</td>
3864 <td>Out</td>
3865 </tr>
3866 <tr>
3867 <td>0</td>
3868 <td>0</td>
3869 <td>0</td>
3870 </tr>
3871 <tr>
3872 <td>0</td>
3873 <td>1</td>
3874 <td>1</td>
3875 </tr>
3876 <tr>
3877 <td>1</td>
3878 <td>0</td>
3879 <td>1</td>
3880 </tr>
3881 <tr>
3882 <td>1</td>
3883 <td>1</td>
3884 <td>1</td>
3885 </tr>
3886 </tbody>
3887</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3888
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3889<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3890<pre>
3891 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3892 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3893 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3894</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3895
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3896</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3897
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3898<!-- _______________________________________________________________________ -->
3899<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3900Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3901
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3902<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3903
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3904<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3905<pre>
3906 &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]3907</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3908
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3909<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3910<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3911 its two operands. The <tt>xor</tt> is used to implement the "one's
3912 complement" operation, which is the "~" operator in C.</p>
3913
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3914<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3915<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3916 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3917 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3918
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3919<h5>Semantics:</h5>
3920<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3921
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3922<table border="1" cellspacing="0" cellpadding="4">
3923 <tbody>
3924 <tr>
3925 <td>In0</td>
3926 <td>In1</td>
3927 <td>Out</td>
3928 </tr>
3929 <tr>
3930 <td>0</td>
3931 <td>0</td>
3932 <td>0</td>
3933 </tr>
3934 <tr>
3935 <td>0</td>
3936 <td>1</td>
3937 <td>1</td>
3938 </tr>
3939 <tr>
3940 <td>1</td>
3941 <td>0</td>
3942 <td>1</td>
3943 </tr>
3944 <tr>
3945 <td>1</td>
3946 <td>1</td>
3947 <td>0</td>
3948 </tr>
3949 </tbody>
3950</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3951
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3952<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3953<pre>
3954 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3955 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3956 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3957 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3958</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3959
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3960</div>
3961
3962<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3963<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3964 <a name="vectorops">Vector Operations</a>
3965</div>
3966
3967<div class="doc_text">
3968
3969<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3970 target-independent manner. These instructions cover the element-access and
3971 vector-specific operations needed to process vectors effectively. While LLVM
3972 does directly support these vector operations, many sophisticated algorithms
3973 will want to use target-specific intrinsics to take full advantage of a
3974 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3975
3976</div>
3977
3978<!-- _______________________________________________________________________ -->
3979<div class="doc_subsubsection">
3980 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3981</div>
3982
3983<div class="doc_text">
3984
3985<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3986<pre>
3987 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3988</pre>
3989
3990<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3991<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3992 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3993
3994
3995<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3996<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3997 of <a href="#t_vector">vector</a> type. The second operand is an index
3998 indicating the position from which to extract the element. The index may be
3999 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4000
4001<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4002<p>The result is a scalar of the same type as the element type of
4003 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4004 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4005 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4006
4007<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4008<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4009 &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]4010</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4011
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4012</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4013
4014<!-- _______________________________________________________________________ -->
4015<div class="doc_subsubsection">
4016 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4017</div>
4018
4019<div class="doc_text">
4020
4021<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4022<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]4023 &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]4024</pre>
4025
4026<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4027<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4028 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4029
4030<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4031<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4032 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4033 whose type must equal the element type of the first operand. The third
4034 operand is an index indicating the position at which to insert the value.
4035 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4036
4037<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4038<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4039 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4040 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4041 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4042
4043<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4044<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4045 &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]4046</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4047
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4048</div>
4049
4050<!-- _______________________________________________________________________ -->
4051<div class="doc_subsubsection">
4052 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4053</div>
4054
4055<div class="doc_text">
4056
4057<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4058<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]4059 &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]4060</pre>
4061
4062<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4063<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4064 from two input vectors, returning a vector with the same element type as the
4065 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4066
4067<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4068<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4069 with types that match each other. The third argument is a shuffle mask whose
4070 element type is always 'i32'. The result of the instruction is a vector
4071 whose length is the same as the shuffle mask and whose element type is the
4072 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4073
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4074<p>The shuffle mask operand is required to be a constant vector with either
4075 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4076
4077<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4078<p>The elements of the two input vectors are numbered from left to right across
4079 both of the vectors. The shuffle mask operand specifies, for each element of
4080 the result vector, which element of the two input vectors the result element
4081 gets. The element selector may be undef (meaning "don't care") and the
4082 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4083
4084<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4085<pre>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4086 &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]4087 &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]4088 &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]4089 &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]4090 &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]4091 &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]4092 &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]4093 &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]4094</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4095
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4096</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4097
4098<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4099<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4100 <a name="aggregateops">Aggregate Operations</a>
4101</div>
4102
4103<div class="doc_text">
4104
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4105<p>LLVM supports several instructions for working with
4106 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4107
4108</div>
4109
4110<!-- _______________________________________________________________________ -->
4111<div class="doc_subsubsection">
4112 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4113</div>
4114
4115<div class="doc_text">
4116
4117<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4118<pre>
4119 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4120</pre>
4121
4122<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4123<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4124 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4125
4126<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4127<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4128 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4129 <a href="#t_array">array</a> type. The operands are constant indices to
4130 specify which value to extract in a similar manner as indices in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4131 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4132
4133<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4134<p>The result is the value at the position in the aggregate specified by the
4135 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4136
4137<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4138<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4139 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4140</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4141
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4142</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4143
4144<!-- _______________________________________________________________________ -->
4145<div class="doc_subsubsection">
4146 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4147</div>
4148
4149<div class="doc_text">
4150
4151<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4152<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]4153 &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]4154</pre>
4155
4156<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4157<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4158 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4159
4160<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4161<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4162 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4163 <a href="#t_array">array</a> type. The second operand is a first-class
4164 value to insert. The following operands are constant indices indicating
4165 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]4166 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4167 value to insert must have the same type as the value identified by the
4168 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4169
4170<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4171<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4172 that of <tt>val</tt> except that the value at the position specified by the
4173 indices is that of <tt>elt</tt>.</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>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]4177 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4178 %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]4179</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4180
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4181</div>
4182
4183
4184<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4185<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4186 <a name="memoryops">Memory Access and Addressing Operations</a>
4187</div>
4188
4189<div class="doc_text">
4190
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4191<p>A key design point of an SSA-based representation is how it represents
4192 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]4193 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4194 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4195
4196</div>
4197
4198<!-- _______________________________________________________________________ -->
4199<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4200 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4201</div>
4202
4203<div class="doc_text">
4204
4205<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4206<pre>
4207 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
4208</pre>
4209
4210<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4211<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4212 currently executing function, to be automatically released when this function
4213 returns to its caller. The object is always allocated in the generic address
4214 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4215
4216<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4217<p>The '<tt>alloca</tt>' instruction
4218 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4219 runtime stack, returning a pointer of the appropriate type to the program.
4220 If "NumElements" is specified, it is the number of elements allocated,
4221 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4222 specified, the value result of the allocation is guaranteed to be aligned to
4223 at least that boundary. If not specified, or if zero, the target can choose
4224 to align the allocation on any convenient boundary compatible with the
4225 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4226
4227<p>'<tt>type</tt>' may be any sized type.</p>
4228
4229<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]4230<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4231 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4232 memory is automatically released when the function returns. The
4233 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4234 variables that must have an address available. When the function returns
4235 (either with the <tt><a href="#i_ret">ret</a></tt>
4236 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4237 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4238
4239<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4240<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]4241 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4242 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4243 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4244 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4245</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4246
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4247</div>
4248
4249<!-- _______________________________________________________________________ -->
4250<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4251Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4252
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4253<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4254
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4255<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4256<pre>
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4257 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4258 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4259 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4260</pre>
4261
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4262<h5>Overview:</h5>
4263<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4264
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4265<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4266<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4267 from which to load. The pointer must point to
4268 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4269 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]4270 number or order of execution of this <tt>load</tt> with other <a
4271 href="#volatile">volatile operations</a>.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4272
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4273<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4274 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]4275 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4276 alignment for the target. It is the responsibility of the code emitter to
4277 ensure that the alignment information is correct. Overestimating the
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4278 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4279 produce less efficient code. An alignment of 1 is always safe.</p>
4280
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4281<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4282 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4283 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4284 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4285 and code generator that this load is not expected to be reused in the cache.
4286 The code generator may select special instructions to save cache bandwidth,
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4287 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4288
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4289<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4290<p>The location of memory pointed to is loaded. If the value being loaded is of
4291 scalar type then the number of bytes read does not exceed the minimum number
4292 of bytes needed to hold all bits of the type. For example, loading an
4293 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4294 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4295 is undefined if the value was not originally written using a store of the
4296 same type.</p>
4297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4298<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4299<pre>
4300 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4301 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4302 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
4303</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4304
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4305</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4306
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4307<!-- _______________________________________________________________________ -->
4308<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4309Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4310
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4311<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4312
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4313<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4314<pre>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4315 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4316 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]4317</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4318
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4319<h5>Overview:</h5>
4320<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4321
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4322<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4323<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4324 and an address at which to store it. The type of the
4325 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4326 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]4327 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4328 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4329 order of execution of this <tt>store</tt> with other <a
4330 href="#volatile">volatile operations</a>.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4331
4332<p>The optional constant "align" argument specifies the alignment of the
4333 operation (that is, the alignment of the memory address). A value of 0 or an
4334 omitted "align" argument means that the operation has the preferential
4335 alignment for the target. It is the responsibility of the code emitter to
4336 ensure that the alignment information is correct. Overestimating the
4337 alignment results in an undefined behavior. Underestimating the alignment may
4338 produce less efficient code. An alignment of 1 is always safe.</p>
4339
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4340<p>The optional !nontemporal metadata must reference a single metatadata
4341 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4342 value 1. The existence of the !nontemporal metatadata on the
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4343 instruction tells the optimizer and code generator that this load is
4344 not expected to be reused in the cache. The code generator may
4345 select special instructions to save cache bandwidth, such as the
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4346 MOVNT instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4347
4348
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4349<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4350<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4351 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4352 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4353 does not exceed the minimum number of bytes needed to hold all bits of the
4354 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4355 writing a value of a type like <tt>i20</tt> with a size that is not an
4356 integral number of bytes, it is unspecified what happens to the extra bits
4357 that do not belong to the type, but they will typically be overwritten.</p>
4358
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4359<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4360<pre>
4361 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4362 store i32 3, i32* %ptr <i>; yields {void}</i>
4363 %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]4364</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4365
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4366</div>
4367
4368<!-- _______________________________________________________________________ -->
4369<div class="doc_subsubsection">
4370 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4371</div>
4372
4373<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4374
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4375<h5>Syntax:</h5>
4376<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4377 &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]4378 &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]4379</pre>
4380
4381<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4382<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4383 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4384 It performs address calculation only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4385
4386<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4387<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4388 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4389 elements of the aggregate object are indexed. The interpretation of each
4390 index is dependent on the type being indexed into. The first index always
4391 indexes the pointer value given as the first argument, the second index
4392 indexes a value of the type pointed to (not necessarily the value directly
4393 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4394 indexed into must be a pointer value, subsequent types can be arrays,
4395 vectors, structs and unions. Note that subsequent types being indexed into
4396 can never be pointers, since that would require loading the pointer before
4397 continuing calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4398
4399<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]4400 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4401 integer <b>constants</b> are allowed. When indexing into an array, pointer
4402 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]4403 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4404
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4405<p>For example, let's consider a C code fragment and how it gets compiled to
4406 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4407
4408<div class="doc_code">
4409<pre>
4410struct RT {
4411 char A;
4412 int B[10][20];
4413 char C;
4414};
4415struct ST {
4416 int X;
4417 double Y;
4418 struct RT Z;
4419};
4420
4421int *foo(struct ST *s) {
4422 return &amp;s[1].Z.B[5][13];
4423}
4424</pre>
4425</div>
4426
4427<p>The LLVM code generated by the GCC frontend is:</p>
4428
4429<div class="doc_code">
4430<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4431%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4432%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4433
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4434define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4435entry:
4436 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4437 ret i32* %reg
4438}
4439</pre>
4440</div>
4441
4442<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4443<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]4444 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4445 }</tt>' type, a structure. The second index indexes into the third element
4446 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4447 i8 }</tt>' type, another structure. The third index indexes into the second
4448 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4449 array. The two dimensions of the array are subscripted into, yielding an
4450 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4451 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4452
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4453<p>Note that it is perfectly legal to index partially through a structure,
4454 returning a pointer to an inner element. Because of this, the LLVM code for
4455 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4456
4457<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4458 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4459 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4460 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4461 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4462 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4463 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4464 ret i32* %t5
4465 }
4466</pre>
4467
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4468<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohmanf7263862010-04-23 15:23:32 +0000[diff] [blame]4469 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4470 base pointer is not an <i>in bounds</i> address of an allocated object,
4471 or if any of the addresses that would be formed by successive addition of
4472 the offsets implied by the indices to the base address with infinitely
4473 precise arithmetic are not an <i>in bounds</i> address of that allocated
4474 object. The <i>in bounds</i> addresses for an allocated object are all
4475 the addresses that point into the object, plus the address one byte past
4476 the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4477
4478<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4479 the base address with silently-wrapping two's complement arithmetic, and
4480 the result value of the <tt>getelementptr</tt> may be outside the object
4481 pointed to by the base pointer. The result value may not necessarily be
4482 used to access memory though, even if it happens to point into allocated
4483 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4484 section for more information.</p>
4485
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4486<p>The getelementptr instruction is often confusing. For some more insight into
4487 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4488
4489<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4490<pre>
4491 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4492 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4493 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4494 %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]4495 <i>; yields i8*:eptr</i>
4496 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4497 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4498 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4499</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4501</div>
4502
4503<!-- ======================================================================= -->
4504<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4505</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4506
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4507<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4508
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4509<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4510 which all take a single operand and a type. They perform various bit
4511 conversions on the operand.</p>
4512
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4513</div>
4514
4515<!-- _______________________________________________________________________ -->
4516<div class="doc_subsubsection">
4517 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4518</div>
4519<div class="doc_text">
4520
4521<h5>Syntax:</h5>
4522<pre>
4523 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4524</pre>
4525
4526<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4527<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4528 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4529
4530<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4531<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4532 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4533 size and type of the result, which must be
4534 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4535 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4536 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4537
4538<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4539<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4540 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4541 source size must be larger than the destination size, <tt>trunc</tt> cannot
4542 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4543
4544<h5>Example:</h5>
4545<pre>
4546 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4547 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4548 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4549</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4550
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4551</div>
4552
4553<!-- _______________________________________________________________________ -->
4554<div class="doc_subsubsection">
4555 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4556</div>
4557<div class="doc_text">
4558
4559<h5>Syntax:</h5>
4560<pre>
4561 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4562</pre>
4563
4564<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4565<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4566 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4567
4568
4569<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4570<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]4571 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4572 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]4573 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4574 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4575
4576<h5>Semantics:</h5>
4577<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]4578 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4579
4580<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4581
4582<h5>Example:</h5>
4583<pre>
4584 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4585 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4586</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4587
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4588</div>
4589
4590<!-- _______________________________________________________________________ -->
4591<div class="doc_subsubsection">
4592 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4593</div>
4594<div class="doc_text">
4595
4596<h5>Syntax:</h5>
4597<pre>
4598 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4599</pre>
4600
4601<h5>Overview:</h5>
4602<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4603
4604<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4605<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]4606 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4607 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]4608 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4609 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4610
4611<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4612<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4613 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4614 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4615
4616<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4617
4618<h5>Example:</h5>
4619<pre>
4620 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4621 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4622</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4624</div>
4625
4626<!-- _______________________________________________________________________ -->
4627<div class="doc_subsubsection">
4628 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4629</div>
4630
4631<div class="doc_text">
4632
4633<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4634<pre>
4635 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4636</pre>
4637
4638<h5>Overview:</h5>
4639<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4640 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4641
4642<h5>Arguments:</h5>
4643<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4644 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4645 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]4646 <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]4647 <i>no-op cast</i>.</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>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4651 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4652 <a href="#t_floating">floating point</a> type. If the value cannot fit
4653 within the destination type, <tt>ty2</tt>, then the results are
4654 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4655
4656<h5>Example:</h5>
4657<pre>
4658 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4659 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</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_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4667</div>
4668<div class="doc_text">
4669
4670<h5>Syntax:</h5>
4671<pre>
4672 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4673</pre>
4674
4675<h5>Overview:</h5>
4676<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]4677 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4678
4679<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4680<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4681 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4682 a <a href="#t_floating">floating point</a> type to cast it to. The source
4683 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4684
4685<h5>Semantics:</h5>
4686<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4687 <a href="#t_floating">floating point</a> type to a larger
4688 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4689 used to make a <i>no-op cast</i> because it always changes bits. Use
4690 <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]4691
4692<h5>Example:</h5>
4693<pre>
4694 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4695 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4696</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4697
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4698</div>
4699
4700<!-- _______________________________________________________________________ -->
4701<div class="doc_subsubsection">
4702 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4703</div>
4704<div class="doc_text">
4705
4706<h5>Syntax:</h5>
4707<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4708 &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]4709</pre>
4710
4711<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4712<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4713 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4714
4715<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4716<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4717 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4718 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4719 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4720 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4721
4722<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4723<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4724 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4725 towards zero) unsigned integer value. If the value cannot fit
4726 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4727
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4728<h5>Example:</h5>
4729<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4730 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4731 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4732 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4733</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4734
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4735</div>
4736
4737<!-- _______________________________________________________________________ -->
4738<div class="doc_subsubsection">
4739 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4740</div>
4741<div class="doc_text">
4742
4743<h5>Syntax:</h5>
4744<pre>
4745 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4746</pre>
4747
4748<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4749<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4750 <a href="#t_floating">floating point</a> <tt>value</tt> to
4751 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4752
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4753<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4754<p>The '<tt>fptosi</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>fptosi</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) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4764 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>
4768 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4769 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4770 %Z = fptosi 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_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4778</div>
4779<div class="doc_text">
4780
4781<h5>Syntax:</h5>
4782<pre>
4783 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4784</pre>
4785
4786<h5>Overview:</h5>
4787<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4788 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4789
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4790<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4791<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]4792 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4793 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4794 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4795 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4796
4797<h5>Semantics:</h5>
4798<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4799 integer quantity and converts it to the corresponding floating point
4800 value. If the value cannot fit in the floating point value, the results are
4801 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4803<h5>Example:</h5>
4804<pre>
4805 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4806 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4807</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4808
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4809</div>
4810
4811<!-- _______________________________________________________________________ -->
4812<div class="doc_subsubsection">
4813 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4814</div>
4815<div class="doc_text">
4816
4817<h5>Syntax:</h5>
4818<pre>
4819 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4820</pre>
4821
4822<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4823<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4824 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4825
4826<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4827<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]4828 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4829 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4830 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4831 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4832
4833<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4834<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4835 quantity and converts it to the corresponding floating point value. If the
4836 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4837
4838<h5>Example:</h5>
4839<pre>
4840 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4841 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4842</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4843
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4844</div>
4845
4846<!-- _______________________________________________________________________ -->
4847<div class="doc_subsubsection">
4848 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4849</div>
4850<div class="doc_text">
4851
4852<h5>Syntax:</h5>
4853<pre>
4854 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4855</pre>
4856
4857<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4858<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4859 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4860
4861<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4862<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4863 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4864 <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]4865
4866<h5>Semantics:</h5>
4867<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4868 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4869 truncating or zero extending that value to the size of the integer type. If
4870 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4871 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4872 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4873 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4874
4875<h5>Example:</h5>
4876<pre>
4877 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4878 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4879</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4880
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4881</div>
4882
4883<!-- _______________________________________________________________________ -->
4884<div class="doc_subsubsection">
4885 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4886</div>
4887<div class="doc_text">
4888
4889<h5>Syntax:</h5>
4890<pre>
4891 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4892</pre>
4893
4894<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4895<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4896 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4897
4898<h5>Arguments:</h5>
4899<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4900 value to cast, and a type to cast it to, which must be a
4901 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4902
4903<h5>Semantics:</h5>
4904<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4905 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4906 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4907 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4908 than the size of a pointer then a zero extension is done. If they are the
4909 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4910
4911<h5>Example:</h5>
4912<pre>
4913 %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]4914 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4915 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4916</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4917
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4918</div>
4919
4920<!-- _______________________________________________________________________ -->
4921<div class="doc_subsubsection">
4922 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4923</div>
4924<div class="doc_text">
4925
4926<h5>Syntax:</h5>
4927<pre>
4928 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4929</pre>
4930
4931<h5>Overview:</h5>
4932<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4933 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4934
4935<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4936<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4937 non-aggregate first class value, and a type to cast it to, which must also be
4938 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4939 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4940 identical. If the source type is a pointer, the destination type must also be
4941 a pointer. This instruction supports bitwise conversion of vectors to
4942 integers and to vectors of other types (as long as they have the same
4943 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4944
4945<h5>Semantics:</h5>
4946<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4947 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4948 this conversion. The conversion is done as if the <tt>value</tt> had been
4949 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4950 be converted to other pointer types with this instruction. To convert
4951 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4952 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4953
4954<h5>Example:</h5>
4955<pre>
4956 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4957 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4958 %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]4959</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4960
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4961</div>
4962
4963<!-- ======================================================================= -->
4964<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4965
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4966<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4967
4968<p>The instructions in this category are the "miscellaneous" instructions, which
4969 defy better classification.</p>
4970
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4971</div>
4972
4973<!-- _______________________________________________________________________ -->
4974<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4975</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4976
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4977<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4978
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4979<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4980<pre>
4981 &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]4982</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4983
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4984<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4985<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4986 boolean values based on comparison of its two integer, integer vector, or
4987 pointer operands.</p>
4988
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4989<h5>Arguments:</h5>
4990<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4991 the condition code indicating the kind of comparison to perform. It is not a
4992 value, just a keyword. The possible condition code are:</p>
4993
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4994<ol>
4995 <li><tt>eq</tt>: equal</li>
4996 <li><tt>ne</tt>: not equal </li>
4997 <li><tt>ugt</tt>: unsigned greater than</li>
4998 <li><tt>uge</tt>: unsigned greater or equal</li>
4999 <li><tt>ult</tt>: unsigned less than</li>
5000 <li><tt>ule</tt>: unsigned less or equal</li>
5001 <li><tt>sgt</tt>: signed greater than</li>
5002 <li><tt>sge</tt>: signed greater or equal</li>
5003 <li><tt>slt</tt>: signed less than</li>
5004 <li><tt>sle</tt>: signed less or equal</li>
5005</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5006
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5007<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5008 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5009 typed. They must also be identical types.</p>
5010
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5011<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5012<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5013 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]5014 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]5015 result, as follows:</p>
5016
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5017<ol>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5018 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5019 <tt>false</tt> otherwise. No sign interpretation is necessary or
5020 performed.</li>
5021
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5022 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5023 <tt>false</tt> otherwise. No sign interpretation is necessary or
5024 performed.</li>
5025
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5026 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5027 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5028
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5029 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5030 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5031 to <tt>op2</tt>.</li>
5032
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5033 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5034 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5035
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5036 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5037 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5038
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5039 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5040 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5041
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5042 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5043 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5044 to <tt>op2</tt>.</li>
5045
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5046 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5047 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5048
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5049 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5050 <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]5051</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5052
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5053<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5054 values are compared as if they were integers.</p>
5055
5056<p>If the operands are integer vectors, then they are compared element by
5057 element. The result is an <tt>i1</tt> vector with the same number of elements
5058 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5059
5060<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5061<pre>
5062 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5063 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5064 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5065 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5066 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5067 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
5068</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5069
5070<p>Note that the code generator does not yet support vector types with
5071 the <tt>icmp</tt> instruction.</p>
5072
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5073</div>
5074
5075<!-- _______________________________________________________________________ -->
5076<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5077</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5078
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5079<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5080
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5081<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5082<pre>
5083 &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]5084</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5085
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5086<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5087<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5088 values based on comparison of its operands.</p>
5089
5090<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]5091(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5092
5093<p>If the operands are floating point vectors, then the result type is a vector
5094 of boolean with the same number of elements as the operands being
5095 compared.</p>
5096
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5097<h5>Arguments:</h5>
5098<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5099 the condition code indicating the kind of comparison to perform. It is not a
5100 value, just a keyword. The possible condition code are:</p>
5101
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5102<ol>
5103 <li><tt>false</tt>: no comparison, always returns false</li>
5104 <li><tt>oeq</tt>: ordered and equal</li>
5105 <li><tt>ogt</tt>: ordered and greater than </li>
5106 <li><tt>oge</tt>: ordered and greater than or equal</li>
5107 <li><tt>olt</tt>: ordered and less than </li>
5108 <li><tt>ole</tt>: ordered and less than or equal</li>
5109 <li><tt>one</tt>: ordered and not equal</li>
5110 <li><tt>ord</tt>: ordered (no nans)</li>
5111 <li><tt>ueq</tt>: unordered or equal</li>
5112 <li><tt>ugt</tt>: unordered or greater than </li>
5113 <li><tt>uge</tt>: unordered or greater than or equal</li>
5114 <li><tt>ult</tt>: unordered or less than </li>
5115 <li><tt>ule</tt>: unordered or less than or equal</li>
5116 <li><tt>une</tt>: unordered or not equal</li>
5117 <li><tt>uno</tt>: unordered (either nans)</li>
5118 <li><tt>true</tt>: no comparison, always returns true</li>
5119</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5120
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5121<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5122 <i>unordered</i> means that either operand may be a QNAN.</p>
5123
5124<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5125 a <a href="#t_floating">floating point</a> type or
5126 a <a href="#t_vector">vector</a> of floating point type. They must have
5127 identical types.</p>
5128
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5129<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]5130<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5131 according to the condition code given as <tt>cond</tt>. If the operands are
5132 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]5133 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5134 follows:</p>
5135
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5136<ol>
5137 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5138
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5139 <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]5140 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5141
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5142 <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]5143 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5144
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5145 <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]5146 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5147
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5148 <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]5149 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5150
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5151 <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]5152 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5153
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5154 <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]5155 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5156
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5157 <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]5158
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5159 <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]5160 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5161
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5162 <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]5163 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5164
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5165 <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]5166 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5167
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5168 <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]5169 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5170
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5171 <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]5172 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5173
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5174 <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]5175 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5176
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5177 <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]5178
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5179 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5180</ol>
5181
5182<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5183<pre>
5184 &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]5185 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5186 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5187 &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]5188</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5189
5190<p>Note that the code generator does not yet support vector types with
5191 the <tt>fcmp</tt> instruction.</p>
5192
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5193</div>
5194
5195<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]5196<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5197 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5198</div>
5199
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5200<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5201
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5202<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5203<pre>
5204 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5205</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5206
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5207<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5208<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5209 SSA graph representing the function.</p>
5210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5211<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5212<p>The type of the incoming values is specified with the first type field. After
5213 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5214 one pair for each predecessor basic block of the current block. Only values
5215 of <a href="#t_firstclass">first class</a> type may be used as the value
5216 arguments to the PHI node. Only labels may be used as the label
5217 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5218
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5219<p>There must be no non-phi instructions between the start of a basic block and
5220 the PHI instructions: i.e. PHI instructions must be first in a basic
5221 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5222
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5223<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5224 occur on the edge from the corresponding predecessor block to the current
5225 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5226 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]5227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5228<h5>Semantics:</h5>
5229<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5230 specified by the pair corresponding to the predecessor basic block that
5231 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5232
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5233<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5234<pre>
5235Loop: ; Infinite loop that counts from 0 on up...
5236 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5237 %nextindvar = add i32 %indvar, 1
5238 br label %Loop
5239</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5240
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5241</div>
5242
5243<!-- _______________________________________________________________________ -->
5244<div class="doc_subsubsection">
5245 <a name="i_select">'<tt>select</tt>' Instruction</a>
5246</div>
5247
5248<div class="doc_text">
5249
5250<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5251<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]5252 &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>
5253
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5254 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5255</pre>
5256
5257<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5258<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5259 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5260
5261
5262<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5263<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5264 values indicating the condition, and two values of the
5265 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5266 vectors and the condition is a scalar, then entire vectors are selected, not
5267 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5268
5269<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5270<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5271 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5272
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5273<p>If the condition is a vector of i1, then the value arguments must be vectors
5274 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5275
5276<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5277<pre>
5278 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
5279</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5280
5281<p>Note that the code generator does not yet support conditions
5282 with vector type.</p>
5283
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5284</div>
5285
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5286<!-- _______________________________________________________________________ -->
5287<div class="doc_subsubsection">
5288 <a name="i_call">'<tt>call</tt>' Instruction</a>
5289</div>
5290
5291<div class="doc_text">
5292
5293<h5>Syntax:</h5>
5294<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]5295 &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]5296</pre>
5297
5298<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5299<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
5300
5301<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5302<p>This instruction requires several arguments:</p>
5303
5304<ol>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5305 <li>The optional "tail" marker indicates that the callee function does not
5306 access any allocas or varargs in the caller. Note that calls may be
5307 marked "tail" even if they do not occur before
5308 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5309 present, the function call is eligible for tail call optimization,
5310 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengcc7495c2010-03-08 21:05:02 +0000[diff] [blame]5311 optimized into a jump</a>. The code generator may optimize calls marked
5312 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5313 sibling call optimization</a> when the caller and callee have
5314 matching signatures, or 2) forced tail call optimization when the
5315 following extra requirements are met:
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5316 <ul>
5317 <li>Caller and callee both have the calling
5318 convention <tt>fastcc</tt>.</li>
5319 <li>The call is in tail position (ret immediately follows call and ret
5320 uses value of call or is void).</li>
5321 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman1be84f02010-03-02 01:08:11 +0000[diff] [blame]5322 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5323 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5324 constraints are met.</a></li>
5325 </ul>
5326 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5327
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5328 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5329 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5330 defaults to using C calling conventions. The calling convention of the
5331 call must match the calling convention of the target function, or else the
5332 behavior is undefined.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5333
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5334 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5335 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5336 '<tt>inreg</tt>' attributes are valid here.</li>
5337
5338 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5339 type of the return value. Functions that return no value are marked
5340 <tt><a href="#t_void">void</a></tt>.</li>
5341
5342 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5343 being invoked. The argument types must match the types implied by this
5344 signature. This type can be omitted if the function is not varargs and if
5345 the function type does not return a pointer to a function.</li>
5346
5347 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5348 be invoked. In most cases, this is a direct function invocation, but
5349 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5350 to function value.</li>
5351
5352 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]5353 signature argument types and parameter attributes. All arguments must be
5354 of <a href="#t_firstclass">first class</a> type. If the function
5355 signature indicates the function accepts a variable number of arguments,
5356 the extra arguments can be specified.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5357
5358 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5359 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5360 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5361</ol>
5362
5363<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5364<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5365 a specified function, with its incoming arguments bound to the specified
5366 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5367 function, control flow continues with the instruction after the function
5368 call, and the return value of the function is bound to the result
5369 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5370
5371<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5372<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5373 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5374 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5375 %X = tail call i32 @foo() <i>; yields i32</i>
5376 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5377 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5378
5379 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5380 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5381 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5382 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5383 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5384 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5385</pre>
5386
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5387<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5388standard C99 library as being the C99 library functions, and may perform
5389optimizations or generate code for them under that assumption. This is
5390something we'd like to change in the future to provide better support for
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5391freestanding environments and non-C-based languages.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5392
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5393</div>
5394
5395<!-- _______________________________________________________________________ -->
5396<div class="doc_subsubsection">
5397 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5398</div>
5399
5400<div class="doc_text">
5401
5402<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5403<pre>
5404 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5405</pre>
5406
5407<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5408<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5409 the "variable argument" area of a function call. It is used to implement the
5410 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5411
5412<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5413<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5414 argument. It returns a value of the specified argument type and increments
5415 the <tt>va_list</tt> to point to the next argument. The actual type
5416 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5417
5418<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5419<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5420 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5421 to the next argument. For more information, see the variable argument
5422 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5423
5424<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]5425 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5426 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5427
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5428<p><tt>va_arg</tt> is an LLVM instruction instead of
5429 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5430 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5431
5432<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5433<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5434
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5435<p>Note that the code generator does not yet fully support va_arg on many
5436 targets. Also, it does not currently support va_arg with aggregate types on
5437 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5438
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5439</div>
5440
5441<!-- *********************************************************************** -->
5442<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5443<!-- *********************************************************************** -->
5444
5445<div class="doc_text">
5446
5447<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5448 well known names and semantics and are required to follow certain
5449 restrictions. Overall, these intrinsics represent an extension mechanism for
5450 the LLVM language that does not require changing all of the transformations
5451 in LLVM when adding to the language (or the bitcode reader/writer, the
5452 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5453
5454<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5455 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5456 begin with this prefix. Intrinsic functions must always be external
5457 functions: you cannot define the body of intrinsic functions. Intrinsic
5458 functions may only be used in call or invoke instructions: it is illegal to
5459 take the address of an intrinsic function. Additionally, because intrinsic
5460 functions are part of the LLVM language, it is required if any are added that
5461 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5462
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5463<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5464 family of functions that perform the same operation but on different data
5465 types. Because LLVM can represent over 8 million different integer types,
5466 overloading is used commonly to allow an intrinsic function to operate on any
5467 integer type. One or more of the argument types or the result type can be
5468 overloaded to accept any integer type. Argument types may also be defined as
5469 exactly matching a previous argument's type or the result type. This allows
5470 an intrinsic function which accepts multiple arguments, but needs all of them
5471 to be of the same type, to only be overloaded with respect to a single
5472 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5473
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5474<p>Overloaded intrinsics will have the names of its overloaded argument types
5475 encoded into its function name, each preceded by a period. Only those types
5476 which are overloaded result in a name suffix. Arguments whose type is matched
5477 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5478 can take an integer of any width and returns an integer of exactly the same
5479 integer width. This leads to a family of functions such as
5480 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5481 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5482 suffix is required. Because the argument's type is matched against the return
5483 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5484
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5485<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5486 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5487
5488</div>
5489
5490<!-- ======================================================================= -->
5491<div class="doc_subsection">
5492 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5493</div>
5494
5495<div class="doc_text">
5496
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5497<p>Variable argument support is defined in LLVM with
5498 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5499 intrinsic functions. These functions are related to the similarly named
5500 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5501
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5502<p>All of these functions operate on arguments that use a target-specific value
5503 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5504 not define what this type is, so all transformations should be prepared to
5505 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5506
5507<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]5508 instruction and the variable argument handling intrinsic functions are
5509 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5510
5511<div class="doc_code">
5512<pre>
5513define i32 @test(i32 %X, ...) {
5514 ; Initialize variable argument processing
5515 %ap = alloca i8*
5516 %ap2 = bitcast i8** %ap to i8*
5517 call void @llvm.va_start(i8* %ap2)
5518
5519 ; Read a single integer argument
5520 %tmp = va_arg i8** %ap, i32
5521
5522 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5523 %aq = alloca i8*
5524 %aq2 = bitcast i8** %aq to i8*
5525 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5526 call void @llvm.va_end(i8* %aq2)
5527
5528 ; Stop processing of arguments.
5529 call void @llvm.va_end(i8* %ap2)
5530 ret i32 %tmp
5531}
5532
5533declare void @llvm.va_start(i8*)
5534declare void @llvm.va_copy(i8*, i8*)
5535declare void @llvm.va_end(i8*)
5536</pre>
5537</div>
5538
5539</div>
5540
5541<!-- _______________________________________________________________________ -->
5542<div class="doc_subsubsection">
5543 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5544</div>
5545
5546
5547<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5548
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5549<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5550<pre>
5551 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5552</pre>
5553
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5554<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5555<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5556 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]5557
5558<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5559<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]5560
5561<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5562<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]5563 macro available in C. In a target-dependent way, it initializes
5564 the <tt>va_list</tt> element to which the argument points, so that the next
5565 call to <tt>va_arg</tt> will produce the first variable argument passed to
5566 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5567 need to know the last argument of the function as the compiler can figure
5568 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5569
5570</div>
5571
5572<!-- _______________________________________________________________________ -->
5573<div class="doc_subsubsection">
5574 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5575</div>
5576
5577<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5578
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5579<h5>Syntax:</h5>
5580<pre>
5581 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5582</pre>
5583
5584<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5585<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5586 which has been initialized previously
5587 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5588 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5589
5590<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5591<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5592
5593<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5594<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]5595 macro available in C. In a target-dependent way, it destroys
5596 the <tt>va_list</tt> element to which the argument points. Calls
5597 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5598 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5599 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5600
5601</div>
5602
5603<!-- _______________________________________________________________________ -->
5604<div class="doc_subsubsection">
5605 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5606</div>
5607
5608<div class="doc_text">
5609
5610<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5611<pre>
5612 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5613</pre>
5614
5615<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5616<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5617 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5618
5619<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5620<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]5621 The second argument is a pointer to a <tt>va_list</tt> element to copy
5622 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5623
5624<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5625<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]5626 macro available in C. In a target-dependent way, it copies the
5627 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5628 element. This intrinsic is necessary because
5629 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5630 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5631
5632</div>
5633
5634<!-- ======================================================================= -->
5635<div class="doc_subsection">
5636 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5637</div>
5638
5639<div class="doc_text">
5640
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5641<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5642Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5643intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5644roots on the stack</a>, as well as garbage collector implementations that
5645require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5646barriers. Front-ends for type-safe garbage collected languages should generate
5647these intrinsics to make use of the LLVM garbage collectors. For more details,
5648see <a href="GarbageCollection.html">Accurate Garbage Collection with
5649LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5650
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5651<p>The garbage collection intrinsics only operate on objects in the generic
5652 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5653
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5654</div>
5655
5656<!-- _______________________________________________________________________ -->
5657<div class="doc_subsubsection">
5658 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5659</div>
5660
5661<div class="doc_text">
5662
5663<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5664<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5665 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5666</pre>
5667
5668<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5669<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]5670 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5671
5672<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5673<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5674 root pointer. The second pointer (which must be either a constant or a
5675 global value address) contains the meta-data to be associated with the
5676 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5677
5678<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5679<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]5680 location. At compile-time, the code generator generates information to allow
5681 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5682 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5683 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5684
5685</div>
5686
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5687<!-- _______________________________________________________________________ -->
5688<div class="doc_subsubsection">
5689 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5690</div>
5691
5692<div class="doc_text">
5693
5694<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5695<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5696 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5697</pre>
5698
5699<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5700<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5701 locations, allowing garbage collector implementations that require read
5702 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5703
5704<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5705<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]5706 allocated from the garbage collector. The first object is a pointer to the
5707 start of the referenced object, if needed by the language runtime (otherwise
5708 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5709
5710<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5711<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5712 instruction, but may be replaced with substantially more complex code by the
5713 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5714 may only be used in a function which <a href="#gc">specifies a GC
5715 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5716
5717</div>
5718
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5719<!-- _______________________________________________________________________ -->
5720<div class="doc_subsubsection">
5721 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5722</div>
5723
5724<div class="doc_text">
5725
5726<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5727<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5728 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5729</pre>
5730
5731<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5732<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5733 locations, allowing garbage collector implementations that require write
5734 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5735
5736<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5737<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]5738 object to store it to, and the third is the address of the field of Obj to
5739 store to. If the runtime does not require a pointer to the object, Obj may
5740 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5741
5742<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5743<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5744 instruction, but may be replaced with substantially more complex code by the
5745 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5746 may only be used in a function which <a href="#gc">specifies a GC
5747 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5748
5749</div>
5750
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5751<!-- ======================================================================= -->
5752<div class="doc_subsection">
5753 <a name="int_codegen">Code Generator Intrinsics</a>
5754</div>
5755
5756<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5757
5758<p>These intrinsics are provided by LLVM to expose special features that may
5759 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5760
5761</div>
5762
5763<!-- _______________________________________________________________________ -->
5764<div class="doc_subsubsection">
5765 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5766</div>
5767
5768<div class="doc_text">
5769
5770<h5>Syntax:</h5>
5771<pre>
5772 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5773</pre>
5774
5775<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5776<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5777 target-specific value indicating the return address of the current function
5778 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5779
5780<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5781<p>The argument to this intrinsic indicates which function to return the address
5782 for. Zero indicates the calling function, one indicates its caller, etc.
5783 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5784
5785<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5786<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5787 indicating the return address of the specified call frame, or zero if it
5788 cannot be identified. The value returned by this intrinsic is likely to be
5789 incorrect or 0 for arguments other than zero, so it should only be used for
5790 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5791
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5792<p>Note that calling this intrinsic does not prevent function inlining or other
5793 aggressive transformations, so the value returned may not be that of the
5794 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5795
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5796</div>
5797
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5798<!-- _______________________________________________________________________ -->
5799<div class="doc_subsubsection">
5800 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5801</div>
5802
5803<div class="doc_text">
5804
5805<h5>Syntax:</h5>
5806<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5807 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5808</pre>
5809
5810<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5811<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5812 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5813
5814<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5815<p>The argument to this intrinsic indicates which function to return the frame
5816 pointer for. Zero indicates the calling function, one indicates its caller,
5817 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5818
5819<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5820<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5821 indicating the frame address of the specified call frame, or zero if it
5822 cannot be identified. The value returned by this intrinsic is likely to be
5823 incorrect or 0 for arguments other than zero, so it should only be used for
5824 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5825
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5826<p>Note that calling this intrinsic does not prevent function inlining or other
5827 aggressive transformations, so the value returned may not be that of the
5828 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5829
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5830</div>
5831
5832<!-- _______________________________________________________________________ -->
5833<div class="doc_subsubsection">
5834 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5835</div>
5836
5837<div class="doc_text">
5838
5839<h5>Syntax:</h5>
5840<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5841 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5842</pre>
5843
5844<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5845<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5846 of the function stack, for use
5847 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5848 useful for implementing language features like scoped automatic variable
5849 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5850
5851<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5852<p>This intrinsic returns a opaque pointer value that can be passed
5853 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5854 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5855 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5856 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5857 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5858 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5859
5860</div>
5861
5862<!-- _______________________________________________________________________ -->
5863<div class="doc_subsubsection">
5864 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5865</div>
5866
5867<div class="doc_text">
5868
5869<h5>Syntax:</h5>
5870<pre>
5871 declare void @llvm.stackrestore(i8 * %ptr)
5872</pre>
5873
5874<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5875<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5876 the function stack to the state it was in when the
5877 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5878 executed. This is useful for implementing language features like scoped
5879 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5880
5881<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5882<p>See the description
5883 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5884
5885</div>
5886
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5887<!-- _______________________________________________________________________ -->
5888<div class="doc_subsubsection">
5889 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5890</div>
5891
5892<div class="doc_text">
5893
5894<h5>Syntax:</h5>
5895<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5896 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]5897</pre>
5898
5899<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5900<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5901 insert a prefetch instruction if supported; otherwise, it is a noop.
5902 Prefetches have no effect on the behavior of the program but can change its
5903 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5904
5905<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5906<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5907 specifier determining if the fetch should be for a read (0) or write (1),
5908 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5909 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5910 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5911
5912<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5913<p>This intrinsic does not modify the behavior of the program. In particular,
5914 prefetches cannot trap and do not produce a value. On targets that support
5915 this intrinsic, the prefetch can provide hints to the processor cache for
5916 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5917
5918</div>
5919
5920<!-- _______________________________________________________________________ -->
5921<div class="doc_subsubsection">
5922 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5923</div>
5924
5925<div class="doc_text">
5926
5927<h5>Syntax:</h5>
5928<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5929 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5930</pre>
5931
5932<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5933<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5934 Counter (PC) in a region of code to simulators and other tools. The method
5935 is target specific, but it is expected that the marker will use exported
5936 symbols to transmit the PC of the marker. The marker makes no guarantees
5937 that it will remain with any specific instruction after optimizations. It is
5938 possible that the presence of a marker will inhibit optimizations. The
5939 intended use is to be inserted after optimizations to allow correlations of
5940 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5941
5942<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5943<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5944
5945<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5946<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5947 not support this intrinsic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5948
5949</div>
5950
5951<!-- _______________________________________________________________________ -->
5952<div class="doc_subsubsection">
5953 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5954</div>
5955
5956<div class="doc_text">
5957
5958<h5>Syntax:</h5>
5959<pre>
5960 declare i64 @llvm.readcyclecounter( )
5961</pre>
5962
5963<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5964<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5965 counter register (or similar low latency, high accuracy clocks) on those
5966 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5967 should map to RPCC. As the backing counters overflow quickly (on the order
5968 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5969
5970<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5971<p>When directly supported, reading the cycle counter should not modify any
5972 memory. Implementations are allowed to either return a application specific
5973 value or a system wide value. On backends without support, this is lowered
5974 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5975
5976</div>
5977
5978<!-- ======================================================================= -->
5979<div class="doc_subsection">
5980 <a name="int_libc">Standard C Library Intrinsics</a>
5981</div>
5982
5983<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5984
5985<p>LLVM provides intrinsics for a few important standard C library functions.
5986 These intrinsics allow source-language front-ends to pass information about
5987 the alignment of the pointer arguments to the code generator, providing
5988 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5989
5990</div>
5991
5992<!-- _______________________________________________________________________ -->
5993<div class="doc_subsubsection">
5994 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5995</div>
5996
5997<div class="doc_text">
5998
5999<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6000<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]6001 integer bit width and for different address spaces. Not all targets support
6002 all bit widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6003
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6004<pre>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6005 declare void @llvm.memcpy.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6006 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6007 declare void @llvm.memcpy.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6008 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6009</pre>
6010
6011<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6012<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6013 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6014
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6015<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6016 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6017 and the pointers can be in specified address spaces.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6018
6019<h5>Arguments:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6020
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6021<p>The first argument is a pointer to the destination, the second is a pointer
6022 to the source. The third argument is an integer argument specifying the
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6023 number of bytes to copy, the fourth argument is the alignment of the
6024 source and destination locations, and the fifth is a boolean indicating a
6025 volatile access.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6026
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6027<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]6028 then the caller guarantees that both the source and destination pointers are
6029 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6030
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]6031<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6032 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6033 The detailed access behavior is not very cleanly specified and it is unwise
6034 to depend on it.</p>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6035
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6036<h5>Semantics:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6037
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6038<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6039 source location to the destination location, which are not allowed to
6040 overlap. It copies "len" bytes of memory over. If the argument is known to
6041 be aligned to some boundary, this can be specified as the fourth argument,
6042 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6043
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6044</div>
6045
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6046<!-- _______________________________________________________________________ -->
6047<div class="doc_subsubsection">
6048 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
6049</div>
6050
6051<div class="doc_text">
6052
6053<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]6054<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]6055 width and for different address space. Not all targets support all bit
6056 widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6057
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6058<pre>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6059 declare void @llvm.memmove.p0i8.p0i8.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6060 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
6061 declare void @llvm.memmove.p0i8.p0i8.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
6062 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6063</pre>
6064
6065<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6066<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6067 source location to the destination location. It is similar to the
6068 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6069 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6070
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6071<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6072 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6073 and the pointers can be in specified address spaces.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6074
6075<h5>Arguments:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6076
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6077<p>The first argument is a pointer to the destination, the second is a pointer
6078 to the source. The third argument is an integer argument specifying the
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6079 number of bytes to copy, the fourth argument is the alignment of the
6080 source and destination locations, and the fifth is a boolean indicating a
6081 volatile access.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6082
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6083<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]6084 then the caller guarantees that the source and destination pointers are
6085 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6086
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]6087<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6088 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6089 The detailed access behavior is not very cleanly specified and it is unwise
6090 to depend on it.</p>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6091
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6092<h5>Semantics:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6093
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6094<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6095 source location to the destination location, which may overlap. It copies
6096 "len" bytes of memory over. If the argument is known to be aligned to some
6097 boundary, this can be specified as the fourth argument, otherwise it should
6098 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6099
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6100</div>
6101
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6102<!-- _______________________________________________________________________ -->
6103<div class="doc_subsubsection">
6104 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
6105</div>
6106
6107<div class="doc_text">
6108
6109<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]6110<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]6111 width and for different address spaces. Not all targets support all bit
6112 widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6113
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6114<pre>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6115 declare void @llvm.memset.p0i8.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerc0dfafe2010-04-08 00:54:34 +0000[diff] [blame]6116 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6117 declare void @llvm.memset.p0i8.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerc0dfafe2010-04-08 00:54:34 +0000[diff] [blame]6118 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6119</pre>
6120
6121<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6122<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6123 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6124
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6125<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6126 intrinsic does not return a value, takes extra alignment/volatile arguments,
6127 and the destination can be in an arbitrary address space.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6128
6129<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6130<p>The first argument is a pointer to the destination to fill, the second is the
6131 byte value to fill it with, the third argument is an integer argument
6132 specifying the number of bytes to fill, and the fourth argument is the known
6133 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6134
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6135<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]6136 then the caller guarantees that the destination pointer is aligned to that
6137 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6138
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]6139<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6140 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6141 The detailed access behavior is not very cleanly specified and it is unwise
6142 to depend on it.</p>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6143
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6144<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6145<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6146 at the destination location. If the argument is known to be aligned to some
6147 boundary, this can be specified as the fourth argument, otherwise it should
6148 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6149
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6150</div>
6151
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6152<!-- _______________________________________________________________________ -->
6153<div class="doc_subsubsection">
6154 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
6155</div>
6156
6157<div class="doc_text">
6158
6159<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6160<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6161 floating point or vector of floating point type. Not all targets support all
6162 types however.</p>
6163
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6164<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]6165 declare float @llvm.sqrt.f32(float %Val)
6166 declare double @llvm.sqrt.f64(double %Val)
6167 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6168 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6169 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6170</pre>
6171
6172<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6173<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6174 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6175 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6176 behavior for negative numbers other than -0.0 (which allows for better
6177 optimization, because there is no need to worry about errno being
6178 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]6179
6180<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6181<p>The argument and return value are floating point numbers of the same
6182 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6183
6184<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6185<p>This function returns the sqrt of the specified operand if it is a
6186 nonnegative floating point number.</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
6190<!-- _______________________________________________________________________ -->
6191<div class="doc_subsubsection">
6192 <a name="int_powi">'<tt>llvm.powi.*</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.powi</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.powi.f32(float %Val, i32 %power)
6204 declare double @llvm.powi.f64(double %Val, i32 %power)
6205 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6206 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6207 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
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.powi.*</tt>' intrinsics return the first operand raised to the
6212 specified (positive or negative) power. The order of evaluation of
6213 multiplications is not defined. When a vector of floating point type is
6214 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6215
6216<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6217<p>The second argument is an integer power, and the first is a value to raise to
6218 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6219
6220<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6221<p>This function returns the first value raised to the second power with an
6222 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6223
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6224</div>
6225
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6226<!-- _______________________________________________________________________ -->
6227<div class="doc_subsubsection">
6228 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6229</div>
6230
6231<div class="doc_text">
6232
6233<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6234<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6235 floating point or vector of floating point type. Not all targets support all
6236 types however.</p>
6237
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6238<pre>
6239 declare float @llvm.sin.f32(float %Val)
6240 declare double @llvm.sin.f64(double %Val)
6241 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6242 declare fp128 @llvm.sin.f128(fp128 %Val)
6243 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6244</pre>
6245
6246<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6247<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6248
6249<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6250<p>The argument and return value are floating point numbers of the same
6251 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6252
6253<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6254<p>This function returns the sine of the specified operand, returning the same
6255 values as the libm <tt>sin</tt> functions would, and handles error conditions
6256 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6257
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6258</div>
6259
6260<!-- _______________________________________________________________________ -->
6261<div class="doc_subsubsection">
6262 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6263</div>
6264
6265<div class="doc_text">
6266
6267<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6268<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6269 floating point or vector of floating point type. Not all targets support all
6270 types however.</p>
6271
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6272<pre>
6273 declare float @llvm.cos.f32(float %Val)
6274 declare double @llvm.cos.f64(double %Val)
6275 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6276 declare fp128 @llvm.cos.f128(fp128 %Val)
6277 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6278</pre>
6279
6280<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6281<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6282
6283<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6284<p>The argument and return value are floating point numbers of the same
6285 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6286
6287<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6288<p>This function returns the cosine of the specified operand, returning the same
6289 values as the libm <tt>cos</tt> functions would, and handles error conditions
6290 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6291
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6292</div>
6293
6294<!-- _______________________________________________________________________ -->
6295<div class="doc_subsubsection">
6296 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6297</div>
6298
6299<div class="doc_text">
6300
6301<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6302<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6303 floating point or vector of floating point type. Not all targets support all
6304 types however.</p>
6305
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6306<pre>
6307 declare float @llvm.pow.f32(float %Val, float %Power)
6308 declare double @llvm.pow.f64(double %Val, double %Power)
6309 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6310 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6311 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6312</pre>
6313
6314<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6315<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6316 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6317
6318<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6319<p>The second argument is a floating point power, and the first is a value to
6320 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6321
6322<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6323<p>This function returns the first value raised to the second power, returning
6324 the same values as the libm <tt>pow</tt> functions would, and handles error
6325 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6326
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6327</div>
6328
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6329<!-- ======================================================================= -->
6330<div class="doc_subsection">
6331 <a name="int_manip">Bit Manipulation Intrinsics</a>
6332</div>
6333
6334<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6335
6336<p>LLVM provides intrinsics for a few important bit manipulation operations.
6337 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6338
6339</div>
6340
6341<!-- _______________________________________________________________________ -->
6342<div class="doc_subsubsection">
6343 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
6344</div>
6345
6346<div class="doc_text">
6347
6348<h5>Syntax:</h5>
6349<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6350 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6351
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6352<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6353 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6354 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6355 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6356</pre>
6357
6358<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6359<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6360 values with an even number of bytes (positive multiple of 16 bits). These
6361 are useful for performing operations on data that is not in the target's
6362 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6363
6364<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6365<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6366 and low byte of the input i16 swapped. Similarly,
6367 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6368 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6369 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6370 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6371 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6372 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6373
6374</div>
6375
6376<!-- _______________________________________________________________________ -->
6377<div class="doc_subsubsection">
6378 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6379</div>
6380
6381<div class="doc_text">
6382
6383<h5>Syntax:</h5>
6384<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]6385 width. Not all targets support all bit widths however.</p>
6386
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6387<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6388 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6389 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6390 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6391 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6392 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6393</pre>
6394
6395<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6396<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6397 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6398
6399<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6400<p>The only argument is the value to be counted. The argument may be of any
6401 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6402
6403<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6404<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]6405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6406</div>
6407
6408<!-- _______________________________________________________________________ -->
6409<div class="doc_subsubsection">
6410 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6411</div>
6412
6413<div class="doc_text">
6414
6415<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6416<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6417 integer bit width. Not all targets support all bit widths however.</p>
6418
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6419<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6420 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6421 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6422 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6423 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6424 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6425</pre>
6426
6427<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6428<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6429 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6430
6431<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6432<p>The only argument is the value to be counted. The argument may be of any
6433 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6434
6435<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6436<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6437 zeros in a variable. If the src == 0 then the result is the size in bits of
6438 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6439
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6440</div>
6441
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6442<!-- _______________________________________________________________________ -->
6443<div class="doc_subsubsection">
6444 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6445</div>
6446
6447<div class="doc_text">
6448
6449<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6450<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6451 integer bit width. Not all targets support all bit widths however.</p>
6452
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6453<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6454 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6455 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6456 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6457 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6458 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6459</pre>
6460
6461<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6462<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6463 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6464
6465<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6466<p>The only argument is the value to be counted. The argument may be of any
6467 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6468
6469<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6470<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6471 zeros in a variable. If the src == 0 then the result is the size in bits of
6472 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6473
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6474</div>
6475
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6476<!-- ======================================================================= -->
6477<div class="doc_subsection">
6478 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6479</div>
6480
6481<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6482
6483<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6484
6485</div>
6486
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6487<!-- _______________________________________________________________________ -->
6488<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6489 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6490</div>
6491
6492<div class="doc_text">
6493
6494<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6495<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]6496 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6497
6498<pre>
6499 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6500 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6501 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6502</pre>
6503
6504<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6505<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6506 a signed addition of the two arguments, and indicate whether an overflow
6507 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6508
6509<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6510<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]6511 be of integer types of any bit width, but they must have the same bit
6512 width. The second element of the result structure must be of
6513 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6514 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6515
6516<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6517<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6518 a signed addition of the two variables. They return a structure &mdash; the
6519 first element of which is the signed summation, and the second element of
6520 which is a bit specifying if the signed summation resulted in an
6521 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6522
6523<h5>Examples:</h5>
6524<pre>
6525 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6526 %sum = extractvalue {i32, i1} %res, 0
6527 %obit = extractvalue {i32, i1} %res, 1
6528 br i1 %obit, label %overflow, label %normal
6529</pre>
6530
6531</div>
6532
6533<!-- _______________________________________________________________________ -->
6534<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6535 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6536</div>
6537
6538<div class="doc_text">
6539
6540<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6541<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]6542 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6543
6544<pre>
6545 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6546 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6547 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6548</pre>
6549
6550<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6551<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6552 an unsigned addition of the two arguments, and indicate whether a carry
6553 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6554
6555<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6556<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]6557 be of integer types of any bit width, but they must have the same bit
6558 width. The second element of the result structure must be of
6559 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6560 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6561
6562<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6563<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6564 an unsigned addition of the two arguments. They return a structure &mdash;
6565 the first element of which is the sum, and the second element of which is a
6566 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6567
6568<h5>Examples:</h5>
6569<pre>
6570 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6571 %sum = extractvalue {i32, i1} %res, 0
6572 %obit = extractvalue {i32, i1} %res, 1
6573 br i1 %obit, label %carry, label %normal
6574</pre>
6575
6576</div>
6577
6578<!-- _______________________________________________________________________ -->
6579<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6580 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6581</div>
6582
6583<div class="doc_text">
6584
6585<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6586<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]6587 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6588
6589<pre>
6590 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6591 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6592 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6593</pre>
6594
6595<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6596<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6597 a signed subtraction of the two arguments, and indicate whether an overflow
6598 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6599
6600<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6601<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]6602 be of integer types of any bit width, but they must have the same bit
6603 width. The second element of the result structure must be of
6604 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6605 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6606
6607<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6608<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6609 a signed subtraction of the two arguments. They return a structure &mdash;
6610 the first element of which is the subtraction, and the second element of
6611 which is a bit specifying if the signed subtraction resulted in an
6612 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6613
6614<h5>Examples:</h5>
6615<pre>
6616 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6617 %sum = extractvalue {i32, i1} %res, 0
6618 %obit = extractvalue {i32, i1} %res, 1
6619 br i1 %obit, label %overflow, label %normal
6620</pre>
6621
6622</div>
6623
6624<!-- _______________________________________________________________________ -->
6625<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6626 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6627</div>
6628
6629<div class="doc_text">
6630
6631<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6632<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]6633 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6634
6635<pre>
6636 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6637 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6638 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6639</pre>
6640
6641<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6642<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6643 an unsigned subtraction of the two arguments, and indicate whether an
6644 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6645
6646<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6647<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]6648 be of integer types of any bit width, but they must have the same bit
6649 width. The second element of the result structure must be of
6650 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6651 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6652
6653<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6654<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6655 an unsigned subtraction of the two arguments. They return a structure &mdash;
6656 the first element of which is the subtraction, and the second element of
6657 which is a bit specifying if the unsigned subtraction resulted in an
6658 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6659
6660<h5>Examples:</h5>
6661<pre>
6662 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6663 %sum = extractvalue {i32, i1} %res, 0
6664 %obit = extractvalue {i32, i1} %res, 1
6665 br i1 %obit, label %overflow, label %normal
6666</pre>
6667
6668</div>
6669
6670<!-- _______________________________________________________________________ -->
6671<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6672 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6673</div>
6674
6675<div class="doc_text">
6676
6677<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6678<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]6679 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6680
6681<pre>
6682 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6683 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6684 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6685</pre>
6686
6687<h5>Overview:</h5>
6688
6689<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6690 a signed multiplication of the two arguments, and indicate whether an
6691 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6692
6693<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6694<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]6695 be of integer types of any bit width, but they must have the same bit
6696 width. The second element of the result structure must be of
6697 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6698 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6699
6700<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6701<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6702 a signed multiplication of the two arguments. They return a structure &mdash;
6703 the first element of which is the multiplication, and the second element of
6704 which is a bit specifying if the signed multiplication resulted in an
6705 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6706
6707<h5>Examples:</h5>
6708<pre>
6709 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6710 %sum = extractvalue {i32, i1} %res, 0
6711 %obit = extractvalue {i32, i1} %res, 1
6712 br i1 %obit, label %overflow, label %normal
6713</pre>
6714
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6715</div>
6716
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6717<!-- _______________________________________________________________________ -->
6718<div class="doc_subsubsection">
6719 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6720</div>
6721
6722<div class="doc_text">
6723
6724<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6725<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]6726 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6727
6728<pre>
6729 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6730 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6731 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6732</pre>
6733
6734<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6735<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6736 a unsigned multiplication of the two arguments, and indicate whether an
6737 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6738
6739<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6740<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]6741 be of integer types of any bit width, but they must have the same bit
6742 width. The second element of the result structure must be of
6743 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6744 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6745
6746<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6747<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6748 an unsigned multiplication of the two arguments. They return a structure
6749 &mdash; the first element of which is the multiplication, and the second
6750 element of which is a bit specifying if the unsigned multiplication resulted
6751 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6752
6753<h5>Examples:</h5>
6754<pre>
6755 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6756 %sum = extractvalue {i32, i1} %res, 0
6757 %obit = extractvalue {i32, i1} %res, 1
6758 br i1 %obit, label %overflow, label %normal
6759</pre>
6760
6761</div>
6762
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6763<!-- ======================================================================= -->
6764<div class="doc_subsection">
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6765 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6766</div>
6767
6768<div class="doc_text">
6769
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6770<p>Half precision floating point is a storage-only format. This means that it is
6771 a dense encoding (in memory) but does not support computation in the
6772 format.</p>
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6773
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6774<p>This means that code must first load the half-precision floating point
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6775 value as an i16, then convert it to float with <a
6776 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6777 Computation can then be performed on the float value (including extending to
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6778 double etc). To store the value back to memory, it is first converted to
6779 float if needed, then converted to i16 with
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6780 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6781 storing as an i16 value.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6782</div>
6783
6784<!-- _______________________________________________________________________ -->
6785<div class="doc_subsubsection">
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6786 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6787</div>
6788
6789<div class="doc_text">
6790
6791<h5>Syntax:</h5>
6792<pre>
6793 declare i16 @llvm.convert.to.fp16(f32 %a)
6794</pre>
6795
6796<h5>Overview:</h5>
6797<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6798 a conversion from single precision floating point format to half precision
6799 floating point format.</p>
6800
6801<h5>Arguments:</h5>
6802<p>The intrinsic function contains single argument - the value to be
6803 converted.</p>
6804
6805<h5>Semantics:</h5>
6806<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6807 a conversion from single precision floating point format to half precision
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6808 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6809 contains the converted number.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6810
6811<h5>Examples:</h5>
6812<pre>
6813 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6814 store i16 %res, i16* @x, align 2
6815</pre>
6816
6817</div>
6818
6819<!-- _______________________________________________________________________ -->
6820<div class="doc_subsubsection">
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6821 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6822</div>
6823
6824<div class="doc_text">
6825
6826<h5>Syntax:</h5>
6827<pre>
6828 declare f32 @llvm.convert.from.fp16(i16 %a)
6829</pre>
6830
6831<h5>Overview:</h5>
6832<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6833 a conversion from half precision floating point format to single precision
6834 floating point format.</p>
6835
6836<h5>Arguments:</h5>
6837<p>The intrinsic function contains single argument - the value to be
6838 converted.</p>
6839
6840<h5>Semantics:</h5>
6841<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6842 conversion from half single precision floating point format to single
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6843 precision floating point format. The input half-float value is represented by
6844 an <tt>i16</tt> value.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6845
6846<h5>Examples:</h5>
6847<pre>
6848 %a = load i16* @x, align 2
6849 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6850</pre>
6851
6852</div>
6853
6854<!-- ======================================================================= -->
6855<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6856 <a name="int_debugger">Debugger Intrinsics</a>
6857</div>
6858
6859<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6860
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6861<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6862 prefix), are described in
6863 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6864 Level Debugging</a> document.</p>
6865
6866</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6867
6868<!-- ======================================================================= -->
6869<div class="doc_subsection">
6870 <a name="int_eh">Exception Handling Intrinsics</a>
6871</div>
6872
6873<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6874
6875<p>The LLVM exception handling intrinsics (which all start with
6876 <tt>llvm.eh.</tt> prefix), are described in
6877 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6878 Handling</a> document.</p>
6879
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6880</div>
6881
6882<!-- ======================================================================= -->
6883<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6884 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6885</div>
6886
6887<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6888
6889<p>This intrinsic makes it possible to excise one parameter, marked with
6890 the <tt>nest</tt> attribute, from a function. The result is a callable
6891 function pointer lacking the nest parameter - the caller does not need to
6892 provide a value for it. Instead, the value to use is stored in advance in a
6893 "trampoline", a block of memory usually allocated on the stack, which also
6894 contains code to splice the nest value into the argument list. This is used
6895 to implement the GCC nested function address extension.</p>
6896
6897<p>For example, if the function is
6898 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6899 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6900 follows:</p>
6901
6902<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6903<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6904 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6905 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6906 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6907 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6908</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6909</div>
6910
6911<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6912 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6913
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6914</div>
6915
6916<!-- _______________________________________________________________________ -->
6917<div class="doc_subsubsection">
6918 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6919</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6920
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6921<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6922
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6923<h5>Syntax:</h5>
6924<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6925 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]6926</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6927
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6928<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6929<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6930 function pointer suitable for executing it.</p>
6931
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6932<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6933<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6934 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6935 sufficiently aligned block of memory; this memory is written to by the
6936 intrinsic. Note that the size and the alignment are target-specific - LLVM
6937 currently provides no portable way of determining them, so a front-end that
6938 generates this intrinsic needs to have some target-specific knowledge.
6939 The <tt>func</tt> argument must hold a function bitcast to
6940 an <tt>i8*</tt>.</p>
6941
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6942<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6943<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6944 dependent code, turning it into a function. A pointer to this function is
6945 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6946 function pointer type</a> before being called. The new function's signature
6947 is the same as that of <tt>func</tt> with any arguments marked with
6948 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6949 is allowed, and it must be of pointer type. Calling the new function is
6950 equivalent to calling <tt>func</tt> with the same argument list, but
6951 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6952 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6953 by <tt>tramp</tt> is modified, then the effect of any later call to the
6954 returned function pointer is undefined.</p>
6955
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6956</div>
6957
6958<!-- ======================================================================= -->
6959<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6960 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6961</div>
6962
6963<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6964
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6965<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6966 hardware constructs for atomic operations and memory synchronization. This
6967 provides an interface to the hardware, not an interface to the programmer. It
6968 is aimed at a low enough level to allow any programming models or APIs
6969 (Application Programming Interfaces) which need atomic behaviors to map
6970 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6971 hardware provides a "universal IR" for source languages, it also provides a
6972 starting point for developing a "universal" atomic operation and
6973 synchronization IR.</p>
6974
6975<p>These do <em>not</em> form an API such as high-level threading libraries,
6976 software transaction memory systems, atomic primitives, and intrinsic
6977 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6978 application libraries. The hardware interface provided by LLVM should allow
6979 a clean implementation of all of these APIs and parallel programming models.
6980 No one model or paradigm should be selected above others unless the hardware
6981 itself ubiquitously does so.</p>
6982
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6983</div>
6984
6985<!-- _______________________________________________________________________ -->
6986<div class="doc_subsubsection">
6987 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6988</div>
6989<div class="doc_text">
6990<h5>Syntax:</h5>
6991<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6992 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]6993</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6994
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6995<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6996<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6997 specific pairs of memory access types.</p>
6998
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6999<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7000<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7001 The first four arguments enables a specific barrier as listed below. The
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]7002 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7003 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7004
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7005<ul>
7006 <li><tt>ll</tt>: load-load barrier</li>
7007 <li><tt>ls</tt>: load-store barrier</li>
7008 <li><tt>sl</tt>: store-load barrier</li>
7009 <li><tt>ss</tt>: store-store barrier</li>
7010 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7011</ul>
7012
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7013<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7014<p>This intrinsic causes the system to enforce some ordering constraints upon
7015 the loads and stores of the program. This barrier does not
7016 indicate <em>when</em> any events will occur, it only enforces
7017 an <em>order</em> in which they occur. For any of the specified pairs of load
7018 and store operations (f.ex. load-load, or store-load), all of the first
7019 operations preceding the barrier will complete before any of the second
7020 operations succeeding the barrier begin. Specifically the semantics for each
7021 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7022
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7023<ul>
7024 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7025 after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7026 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7027 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7028 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7029 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7030 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7031 load after the barrier begins.</li>
7032</ul>
7033
7034<p>These semantics are applied with a logical "and" behavior when more than one
7035 is enabled in a single memory barrier intrinsic.</p>
7036
7037<p>Backends may implement stronger barriers than those requested when they do
7038 not support as fine grained a barrier as requested. Some architectures do
7039 not need all types of barriers and on such architectures, these become
7040 noops.</p>
7041
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7042<h5>Example:</h5>
7043<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7044%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7045%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7046 store i32 4, %ptr
7047
7048%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
7049 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
7050 <i>; guarantee the above finishes</i>
7051 store i32 8, %ptr <i>; before this begins</i>
7052</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7053
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7054</div>
7055
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7056<!-- _______________________________________________________________________ -->
7057<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7058 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7059</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7060
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7061<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7062
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7063<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7064<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7065 any integer bit width and for different address spaces. Not all targets
7066 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7067
7068<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7069 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
7070 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
7071 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
7072 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]7073</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7074
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7075<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7076<p>This loads a value in memory and compares it to a given value. If they are
7077 equal, it stores a new value into the memory.</p>
7078
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7079<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7080<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7081 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7082 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7083 this integer type. While any bit width integer may be used, targets may only
7084 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7085
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7086<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7087<p>This entire intrinsic must be executed atomically. It first loads the value
7088 in memory pointed to by <tt>ptr</tt> and compares it with the
7089 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7090 memory. The loaded value is yielded in all cases. This provides the
7091 equivalent of an atomic compare-and-swap operation within the SSA
7092 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7093
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7094<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7095<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7096%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7097%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7098 store i32 4, %ptr
7099
7100%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7101%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7102 <i>; yields {i32}:result1 = 4</i>
7103%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7104%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7105
7106%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7107%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7108 <i>; yields {i32}:result2 = 8</i>
7109%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7110
7111%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7112</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7113
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7114</div>
7115
7116<!-- _______________________________________________________________________ -->
7117<div class="doc_subsubsection">
7118 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7119</div>
7120<div class="doc_text">
7121<h5>Syntax:</h5>
7122
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7123<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7124 integer bit width. Not all targets support all bit widths however.</p>
7125
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7126<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7127 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
7128 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
7129 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
7130 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]7131</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7132
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7133<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7134<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7135 the value from memory. It then stores the value in <tt>val</tt> in the memory
7136 at <tt>ptr</tt>.</p>
7137
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7138<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7139<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7140 the <tt>val</tt> argument and the result must be integers of the same bit
7141 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7142 integer type. The targets may only lower integer representations they
7143 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7144
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7145<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7146<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7147 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7148 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7149
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7150<h5>Examples:</h5>
7151<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7152%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7153%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7154 store i32 4, %ptr
7155
7156%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7157%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7158 <i>; yields {i32}:result1 = 4</i>
7159%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7160%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7161
7162%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7163%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7164 <i>; yields {i32}:result2 = 8</i>
7165
7166%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7167%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7168</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7169
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7170</div>
7171
7172<!-- _______________________________________________________________________ -->
7173<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7174 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7175
7176</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7177
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7178<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7179
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7180<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7181<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7182 any integer bit width. Not all targets support all bit widths however.</p>
7183
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7184<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7185 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7186 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7187 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7188 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]7189</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7190
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7191<h5>Overview:</h5>
7192<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7193 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7194
7195<h5>Arguments:</h5>
7196<p>The intrinsic takes two arguments, the first a pointer to an integer value
7197 and the second an integer value. The result is also an integer value. These
7198 integer types can have any bit width, but they must all have the same bit
7199 width. The targets may only lower integer representations they support.</p>
7200
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7201<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7202<p>This intrinsic does a series of operations atomically. It first loads the
7203 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7204 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]7205
7206<h5>Examples:</h5>
7207<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7208%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7209%ptr = bitcast i8* %mallocP to i32*
7210 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7211%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7212 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7213%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7214 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7215%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7216 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7217%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7218</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7219
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7220</div>
7221
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7222<!-- _______________________________________________________________________ -->
7223<div class="doc_subsubsection">
7224 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7225
7226</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7227
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7228<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7229
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7230<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7231<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7232 any integer bit width and for different address spaces. Not all targets
7233 support all bit widths however.</p>
7234
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7235<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7236 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7237 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7238 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7239 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]7240</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7241
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7242<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7243<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7244 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7245
7246<h5>Arguments:</h5>
7247<p>The intrinsic takes two arguments, the first a pointer to an integer value
7248 and the second an integer value. The result is also an integer value. These
7249 integer types can have any bit width, but they must all have the same bit
7250 width. The targets may only lower integer representations they support.</p>
7251
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7252<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7253<p>This intrinsic does a series of operations atomically. It first loads the
7254 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7255 result to <tt>ptr</tt>. It yields the original value stored
7256 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7257
7258<h5>Examples:</h5>
7259<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7260%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7261%ptr = bitcast i8* %mallocP to i32*
7262 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7263%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7264 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7265%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7266 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7267%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7268 <i>; yields {i32}:result3 = 2</i>
7269%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7270</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7271
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7272</div>
7273
7274<!-- _______________________________________________________________________ -->
7275<div class="doc_subsubsection">
7276 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7277 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7278 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7279 <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]7280</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7281
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7282<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7283
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7284<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7285<p>These are overloaded intrinsics. You can
7286 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7287 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7288 bit width and for different address spaces. Not all targets support all bit
7289 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7290
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7291<pre>
7292 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7293 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7294 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7295 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]7296</pre>
7297
7298<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7299 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7300 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7301 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7302 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]7303</pre>
7304
7305<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7306 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7307 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7308 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7309 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]7310</pre>
7311
7312<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7313 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7314 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7315 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7316 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]7317</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7318
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7319<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7320<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7321 the value stored in memory at <tt>ptr</tt>. It yields the original value
7322 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7323
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7324<h5>Arguments:</h5>
7325<p>These intrinsics take two arguments, the first a pointer to an integer value
7326 and the second an integer value. The result is also an integer value. These
7327 integer types can have any bit width, but they must all have the same bit
7328 width. The targets may only lower integer representations they support.</p>
7329
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7330<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7331<p>These intrinsics does a series of operations atomically. They first load the
7332 value stored at <tt>ptr</tt>. They then do the bitwise
7333 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7334 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7335
7336<h5>Examples:</h5>
7337<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7338%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7339%ptr = bitcast i8* %mallocP to i32*
7340 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7341%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7342 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7343%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7344 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7345%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7346 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7347%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7348 <i>; yields {i32}:result3 = FF</i>
7349%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7350</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7351
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7352</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7353
7354<!-- _______________________________________________________________________ -->
7355<div class="doc_subsubsection">
7356 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7357 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7358 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7359 <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]7360</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7361
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7362<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7363
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7364<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7365<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7366 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7367 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7368 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7369
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7370<pre>
7371 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7372 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7373 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7374 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]7375</pre>
7376
7377<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7378 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7379 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7380 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7381 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]7382</pre>
7383
7384<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7385 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7386 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7387 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7388 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]7389</pre>
7390
7391<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7392 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7393 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7394 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7395 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]7396</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7397
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7398<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7399<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7400 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7401 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7402
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7403<h5>Arguments:</h5>
7404<p>These intrinsics take two arguments, the first a pointer to an integer value
7405 and the second an integer value. The result is also an integer value. These
7406 integer types can have any bit width, but they must all have the same bit
7407 width. The targets may only lower integer representations they support.</p>
7408
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7409<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7410<p>These intrinsics does a series of operations atomically. They first load the
7411 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7412 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7413 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7414
7415<h5>Examples:</h5>
7416<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7417%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7418%ptr = bitcast i8* %mallocP to i32*
7419 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7420%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7421 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7422%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7423 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7424%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7425 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7426%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7427 <i>; yields {i32}:result3 = 8</i>
7428%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7429</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7430
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7431</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7432
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7433
7434<!-- ======================================================================= -->
7435<div class="doc_subsection">
7436 <a name="int_memorymarkers">Memory Use Markers</a>
7437</div>
7438
7439<div class="doc_text">
7440
7441<p>This class of intrinsics exists to information about the lifetime of memory
7442 objects and ranges where variables are immutable.</p>
7443
7444</div>
7445
7446<!-- _______________________________________________________________________ -->
7447<div class="doc_subsubsection">
7448 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7449</div>
7450
7451<div class="doc_text">
7452
7453<h5>Syntax:</h5>
7454<pre>
7455 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7456</pre>
7457
7458<h5>Overview:</h5>
7459<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7460 object's lifetime.</p>
7461
7462<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7463<p>The first argument is a constant integer representing the size of the
7464 object, or -1 if it is variable sized. The second argument is a pointer to
7465 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7466
7467<h5>Semantics:</h5>
7468<p>This intrinsic indicates that before this point in the code, the value of the
7469 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]7470 never be used and has an undefined value. A load from the pointer that
7471 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7472 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7473
7474</div>
7475
7476<!-- _______________________________________________________________________ -->
7477<div class="doc_subsubsection">
7478 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7479</div>
7480
7481<div class="doc_text">
7482
7483<h5>Syntax:</h5>
7484<pre>
7485 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7486</pre>
7487
7488<h5>Overview:</h5>
7489<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7490 object's lifetime.</p>
7491
7492<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7493<p>The first argument is a constant integer representing the size of the
7494 object, or -1 if it is variable sized. The second argument is a pointer to
7495 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7496
7497<h5>Semantics:</h5>
7498<p>This intrinsic indicates that after this point in the code, the value of the
7499 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7500 never be used and has an undefined value. Any stores into the memory object
7501 following this intrinsic may be removed as dead.
7502
7503</div>
7504
7505<!-- _______________________________________________________________________ -->
7506<div class="doc_subsubsection">
7507 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7508</div>
7509
7510<div class="doc_text">
7511
7512<h5>Syntax:</h5>
7513<pre>
7514 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7515</pre>
7516
7517<h5>Overview:</h5>
7518<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7519 a memory object will not change.</p>
7520
7521<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7522<p>The first argument is a constant integer representing the size of the
7523 object, or -1 if it is variable sized. The second argument is a pointer to
7524 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7525
7526<h5>Semantics:</h5>
7527<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7528 the return value, the referenced memory location is constant and
7529 unchanging.</p>
7530
7531</div>
7532
7533<!-- _______________________________________________________________________ -->
7534<div class="doc_subsubsection">
7535 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7536</div>
7537
7538<div class="doc_text">
7539
7540<h5>Syntax:</h5>
7541<pre>
7542 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7543</pre>
7544
7545<h5>Overview:</h5>
7546<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7547 a memory object are mutable.</p>
7548
7549<h5>Arguments:</h5>
7550<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7551 The second argument is a constant integer representing the size of the
7552 object, or -1 if it is variable sized and the third argument is a pointer
7553 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7554
7555<h5>Semantics:</h5>
7556<p>This intrinsic indicates that the memory is mutable again.</p>
7557
7558</div>
7559
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7560<!-- ======================================================================= -->
7561<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7562 <a name="int_general">General Intrinsics</a>
7563</div>
7564
7565<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7566
7567<p>This class of intrinsics is designed to be generic and has no specific
7568 purpose.</p>
7569
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7570</div>
7571
7572<!-- _______________________________________________________________________ -->
7573<div class="doc_subsubsection">
7574 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7575</div>
7576
7577<div class="doc_text">
7578
7579<h5>Syntax:</h5>
7580<pre>
7581 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7582</pre>
7583
7584<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7585<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7586
7587<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7588<p>The first argument is a pointer to a value, the second is a pointer to a
7589 global string, the third is a pointer to a global string which is the source
7590 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7591
7592<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7593<p>This intrinsic allows annotation of local variables with arbitrary strings.
7594 This can be useful for special purpose optimizations that want to look for
7595 these annotations. These have no other defined use, they are ignored by code
7596 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7597
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7598</div>
7599
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7600<!-- _______________________________________________________________________ -->
7601<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7602 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7603</div>
7604
7605<div class="doc_text">
7606
7607<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7608<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7609 any integer bit width.</p>
7610
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7611<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7612 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7613 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7614 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7615 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7616 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]7617</pre>
7618
7619<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7620<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7621
7622<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7623<p>The first argument is an integer value (result of some expression), the
7624 second is a pointer to a global string, the third is a pointer to a global
7625 string which is the source file name, and the last argument is the line
7626 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7627
7628<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7629<p>This intrinsic allows annotations to be put on arbitrary expressions with
7630 arbitrary strings. This can be useful for special purpose optimizations that
7631 want to look for these annotations. These have no other defined use, they
7632 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7633
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7634</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7635
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7636<!-- _______________________________________________________________________ -->
7637<div class="doc_subsubsection">
7638 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7639</div>
7640
7641<div class="doc_text">
7642
7643<h5>Syntax:</h5>
7644<pre>
7645 declare void @llvm.trap()
7646</pre>
7647
7648<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7649<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7650
7651<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7652<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7653
7654<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7655<p>This intrinsics is lowered to the target dependent trap instruction. If the
7656 target does not have a trap instruction, this intrinsic will be lowered to
7657 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7658
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7659</div>
7660
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7661<!-- _______________________________________________________________________ -->
7662<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7663 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7664</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7665
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7666<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7667
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7668<h5>Syntax:</h5>
7669<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7670 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7671</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7672
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7673<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7674<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7675 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7676 ensure that it is placed on the stack before local variables.</p>
7677
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7678<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7679<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7680 arguments. The first argument is the value loaded from the stack
7681 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7682 that has enough space to hold the value of the guard.</p>
7683
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7684<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7685<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7686 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7687 stack. This is to ensure that if a local variable on the stack is
7688 overwritten, it will destroy the value of the guard. When the function exits,
7689 the guard on the stack is checked against the original guard. If they're
7690 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7691 function.</p>
7692
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7693</div>
7694
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7695<!-- _______________________________________________________________________ -->
7696<div class="doc_subsubsection">
7697 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7698</div>
7699
7700<div class="doc_text">
7701
7702<h5>Syntax:</h5>
7703<pre>
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7704 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7705 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7706</pre>
7707
7708<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7709<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher184f44d2010-01-08 21:42:39 +0000[diff] [blame]7710 to the optimizers to discover at compile time either a) when an
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7711 operation like memcpy will either overflow a buffer that corresponds to
7712 an object, or b) to determine that a runtime check for overflow isn't
7713 necessary. An object in this context means an allocation of a
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7714 specific class, structure, array, or other object.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7715
7716<h5>Arguments:</h5>
7717<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7718 argument is a pointer to or into the <tt>object</tt>. The second argument
7719 is a boolean 0 or 1. This argument determines whether you want the
7720 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7721 1, variables are not allowed.</p>
7722
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7723<h5>Semantics:</h5>
7724<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7725 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7726 (depending on the <tt>type</tt> argument if the size cannot be determined
7727 at compile time.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7728
7729</div>
7730
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7731<!-- *********************************************************************** -->
7732<hr>
7733<address>
7734 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7735 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7736 <a href="http://validator.w3.org/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7738
7739 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7740 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7741 Last modified: $Date$
7742</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7743
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7744</body>
7745</html>