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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 94e59a01f9c8930c75906988d293b93d01d1c59b / . / 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>
Bill Wendlingf8239662010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]28 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
29 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
30 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
31 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
32 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
33 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
34 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner0fee5c22009-10-10 18:26:06 +0000[diff] [blame]35 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]36 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
37 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]40 </ol>
41 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]42 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]43 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]44 <li><a href="#globalvars">Global Variables</a></li>
45 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]46 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]47 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]48 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]49 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]50 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]51 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
52 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]53 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]54 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]55 </ol>
56 </li>
57 <li><a href="#typesystem">Type System</a>
58 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]59 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]60 <li><a href="#t_primitive">Primitive Types</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]61 <ol>
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]62 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]63 <li><a href="#t_floating">Floating Point Types</a></li>
64 <li><a href="#t_void">Void Type</a></li>
65 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]66 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]67 </ol>
68 </li>
69 <li><a href="#t_derived">Derived Types</a>
70 <ol>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]71 <li><a href="#t_aggregate">Aggregate Types</a>
72 <ol>
73 <li><a href="#t_array">Array Type</a></li>
74 <li><a href="#t_struct">Structure Type</a></li>
75 <li><a href="#t_pstruct">Packed Structure Type</a></li>
76 <li><a href="#t_union">Union Type</a></li>
77 <li><a href="#t_vector">Vector Type</a></li>
78 </ol>
79 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]80 <li><a href="#t_function">Function Type</a></li>
81 <li><a href="#t_pointer">Pointer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]82 <li><a href="#t_opaque">Opaque Type</a></li>
83 </ol>
84 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]85 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]86 </ol>
87 </li>
88 <li><a href="#constants">Constants</a>
89 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]90 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]91 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]92 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
93 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]94 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]95 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]96 <li><a href="#constantexprs">Constant Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]97 </ol>
98 </li>
99 <li><a href="#othervalues">Other Values</a>
100 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]101 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]102 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]103 </ol>
104 </li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]105 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
106 <ol>
107 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]108 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
109 Global Variable</a></li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]110 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
111 Global Variable</a></li>
112 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
113 Global Variable</a></li>
114 </ol>
115 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]116 <li><a href="#instref">Instruction Reference</a>
117 <ol>
118 <li><a href="#terminators">Terminator Instructions</a>
119 <ol>
120 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
121 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
122 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]123 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]124 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
125 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
126 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
127 </ol>
128 </li>
129 <li><a href="#binaryops">Binary Operations</a>
130 <ol>
131 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]132 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]133 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]134 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]135 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]136 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]137 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
138 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
139 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
140 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
141 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
142 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
143 </ol>
144 </li>
145 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
146 <ol>
147 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
148 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
149 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
150 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
151 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
152 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
153 </ol>
154 </li>
155 <li><a href="#vectorops">Vector Operations</a>
156 <ol>
157 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
158 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
159 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
160 </ol>
161 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]162 <li><a href="#aggregateops">Aggregate Operations</a>
163 <ol>
164 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
165 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
166 </ol>
167 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]168 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
169 <ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]170 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
171 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
172 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
173 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
174 </ol>
175 </li>
176 <li><a href="#convertops">Conversion Operations</a>
177 <ol>
178 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
179 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
180 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
183 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
184 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
185 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
186 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
187 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
188 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
189 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
190 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]191 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]192 <li><a href="#otherops">Other Operations</a>
193 <ol>
194 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
195 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
196 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
197 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
198 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
199 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
200 </ol>
201 </li>
202 </ol>
203 </li>
204 <li><a href="#intrinsics">Intrinsic Functions</a>
205 <ol>
206 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
207 <ol>
208 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
209 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
210 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
211 </ol>
212 </li>
213 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
214 <ol>
215 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
216 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
217 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
218 </ol>
219 </li>
220 <li><a href="#int_codegen">Code Generator Intrinsics</a>
221 <ol>
222 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
223 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
224 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
225 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
226 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
227 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohmanf15a6b22010-05-26 21:56:15 +0000[diff] [blame]228 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]229 </ol>
230 </li>
231 <li><a href="#int_libc">Standard C Library Intrinsics</a>
232 <ol>
233 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]238 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
239 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]241 </ol>
242 </li>
243 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
244 <ol>
245 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
246 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
247 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
248 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]249 </ol>
250 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]251 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
252 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]253 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
254 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
256 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
257 <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]258 <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]259 </ol>
260 </li>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]261 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
262 <ol>
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]263 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
264 <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]265 </ol>
266 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]267 <li><a href="#int_debugger">Debugger intrinsics</a></li>
268 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]269 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]270 <ol>
271 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]272 </ol>
273 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]274 <li><a href="#int_atomics">Atomic intrinsics</a>
275 <ol>
276 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
277 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
278 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
279 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
280 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
281 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
282 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
283 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
284 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
285 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
286 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
287 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
288 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
289 </ol>
290 </li>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]291 <li><a href="#int_memorymarkers">Memory Use Markers</a>
292 <ol>
293 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
294 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
295 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
296 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
297 </ol>
298 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]299 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]300 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]301 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]302 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]303 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]304 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]305 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]306 '<tt>llvm.trap</tt>' Intrinsic</a></li>
307 <li><a href="#int_stackprotector">
308 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]309 <li><a href="#int_objectsize">
310 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]311 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]312 </li>
313 </ol>
314 </li>
315</ol>
316
317<div class="doc_author">
318 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
319 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
320</div>
321
322<!-- *********************************************************************** -->
323<div class="doc_section"> <a name="abstract">Abstract </a></div>
324<!-- *********************************************************************** -->
325
326<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]327
328<p>This document is a reference manual for the LLVM assembly language. LLVM is
329 a Static Single Assignment (SSA) based representation that provides type
330 safety, low-level operations, flexibility, and the capability of representing
331 'all' high-level languages cleanly. It is the common code representation
332 used throughout all phases of the LLVM compilation strategy.</p>
333
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]334</div>
335
336<!-- *********************************************************************** -->
337<div class="doc_section"> <a name="introduction">Introduction</a> </div>
338<!-- *********************************************************************** -->
339
340<div class="doc_text">
341
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]342<p>The LLVM code representation is designed to be used in three different forms:
343 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
344 for fast loading by a Just-In-Time compiler), and as a human readable
345 assembly language representation. This allows LLVM to provide a powerful
346 intermediate representation for efficient compiler transformations and
347 analysis, while providing a natural means to debug and visualize the
348 transformations. The three different forms of LLVM are all equivalent. This
349 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]350
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]351<p>The LLVM representation aims to be light-weight and low-level while being
352 expressive, typed, and extensible at the same time. It aims to be a
353 "universal IR" of sorts, by being at a low enough level that high-level ideas
354 may be cleanly mapped to it (similar to how microprocessors are "universal
355 IR's", allowing many source languages to be mapped to them). By providing
356 type information, LLVM can be used as the target of optimizations: for
357 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]358 variable is never accessed outside of the current function, allowing it to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]359 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]360
361</div>
362
363<!-- _______________________________________________________________________ -->
364<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
365
366<div class="doc_text">
367
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]368<p>It is important to note that this document describes 'well formed' LLVM
369 assembly language. There is a difference between what the parser accepts and
370 what is considered 'well formed'. For example, the following instruction is
371 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]372
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]373<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]374%x = <a href="#i_add">add</a> i32 1, %x
375</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]376
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]377<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
378 LLVM infrastructure provides a verification pass that may be used to verify
379 that an LLVM module is well formed. This pass is automatically run by the
380 parser after parsing input assembly and by the optimizer before it outputs
381 bitcode. The violations pointed out by the verifier pass indicate bugs in
382 transformation passes or input to the parser.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]383
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]384</div>
385
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]386<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]387
388<!-- *********************************************************************** -->
389<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
390<!-- *********************************************************************** -->
391
392<div class="doc_text">
393
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]394<p>LLVM identifiers come in two basic types: global and local. Global
395 identifiers (functions, global variables) begin with the <tt>'@'</tt>
396 character. Local identifiers (register names, types) begin with
397 the <tt>'%'</tt> character. Additionally, there are three different formats
398 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]399
400<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]401 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]402 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
403 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
404 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
405 other characters in their names can be surrounded with quotes. Special
406 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
407 ASCII code for the character in hexadecimal. In this way, any character
408 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]409
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]410 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]411 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]412
413 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]414 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]415</ol>
416
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]417<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]418 don't need to worry about name clashes with reserved words, and the set of
419 reserved words may be expanded in the future without penalty. Additionally,
420 unnamed identifiers allow a compiler to quickly come up with a temporary
421 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]422
423<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]424 languages. There are keywords for different opcodes
425 ('<tt><a href="#i_add">add</a></tt>',
426 '<tt><a href="#i_bitcast">bitcast</a></tt>',
427 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
428 ('<tt><a href="#t_void">void</a></tt>',
429 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
430 reserved words cannot conflict with variable names, because none of them
431 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]432
433<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]434 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]435
436<p>The easy way:</p>
437
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]438<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]439%result = <a href="#i_mul">mul</a> i32 %X, 8
440</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]441
442<p>After strength reduction:</p>
443
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]444<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]445%result = <a href="#i_shl">shl</a> i32 %X, i8 3
446</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]447
448<p>And the hard way:</p>
449
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]450<pre class="doc_code">
Gabor Greifc0ea7672009-10-28 13:05:07 +0000[diff] [blame]451%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
452%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]453%result = <a href="#i_add">add</a> i32 %1, %1
454</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]455
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]456<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
457 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]458
459<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]460 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]461 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]462
463 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]464 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]465
466 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]467</ol>
468
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]469<p>It also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]470 demonstrating instructions, we will follow an instruction with a comment that
471 defines the type and name of value produced. Comments are shown in italic
472 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]473
474</div>
475
476<!-- *********************************************************************** -->
477<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
478<!-- *********************************************************************** -->
479
480<!-- ======================================================================= -->
481<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
482</div>
483
484<div class="doc_text">
485
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]486<p>LLVM programs are composed of "Module"s, each of which is a translation unit
487 of the input programs. Each module consists of functions, global variables,
488 and symbol table entries. Modules may be combined together with the LLVM
489 linker, which merges function (and global variable) definitions, resolves
490 forward declarations, and merges symbol table entries. Here is an example of
491 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]492
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]493<pre class="doc_code">
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]494<i>; Declare the string constant as a global constant.</i>
495<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]496
497<i>; External declaration of the puts function</i>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]498<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]499
500<i>; Definition of main function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]501define i32 @main() { <i>; i32()* </i>
502 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]503 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]504
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]505 <i>; Call puts function to write out the string to stdout.</i>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]506 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]507 <a href="#i_ret">ret</a> i32 0<br>}
508
509<i>; Named metadata</i>
510!1 = metadata !{i32 41}
511!foo = !{!1, null}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]512</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]513
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]514<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]515 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]516 a <a href="#functionstructure">function definition</a> for
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]517 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
518 "<tt>foo"</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]519
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]520<p>In general, a module is made up of a list of global values, where both
521 functions and global variables are global values. Global values are
522 represented by a pointer to a memory location (in this case, a pointer to an
523 array of char, and a pointer to a function), and have one of the
524 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]525
526</div>
527
528<!-- ======================================================================= -->
529<div class="doc_subsection">
530 <a name="linkage">Linkage Types</a>
531</div>
532
533<div class="doc_text">
534
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]535<p>All Global Variables and Functions have one of the following types of
536 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]537
538<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]539 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingf8239662010-07-01 21:55:59 +0000[diff] [blame]540 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
541 by objects in the current module. In particular, linking code into a
542 module with an private global value may cause the private to be renamed as
543 necessary to avoid collisions. Because the symbol is private to the
544 module, all references can be updated. This doesn't show up in any symbol
545 table in the object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]546
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]547 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendlingf8239662010-07-01 21:55:59 +0000[diff] [blame]548 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
549 assembler and evaluated by the linker. Unlike normal strong symbols, they
550 are removed by the linker from the final linked image (executable or
551 dynamic library).</dd>
552
553 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
554 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
555 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
556 linker. The symbols are removed by the linker from the final linked image
557 (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]558
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]559 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlinge066d262010-06-29 22:34:52 +0000[diff] [blame]560 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]561 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
562 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]563
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]564 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]565 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]566 into the object file corresponding to the LLVM module. They exist to
567 allow inlining and other optimizations to take place given knowledge of
568 the definition of the global, which is known to be somewhere outside the
569 module. Globals with <tt>available_externally</tt> linkage are allowed to
570 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
571 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]572
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]573 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]574 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattnerd16c5512010-01-09 19:15:14 +0000[diff] [blame]575 the same name when linkage occurs. This can be used to implement
576 some forms of inline functions, templates, or other code which must be
577 generated in each translation unit that uses it, but where the body may
578 be overridden with a more definitive definition later. Unreferenced
579 <tt>linkonce</tt> globals are allowed to be discarded. Note that
580 <tt>linkonce</tt> linkage does not actually allow the optimizer to
581 inline the body of this function into callers because it doesn't know if
582 this definition of the function is the definitive definition within the
583 program or whether it will be overridden by a stronger definition.
584 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
585 linkage.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]586
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]587 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]588 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
589 <tt>linkonce</tt> linkage, except that unreferenced globals with
590 <tt>weak</tt> linkage may not be discarded. This is used for globals that
591 are declared "weak" in C source code.</dd>
592
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]593 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]594 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
595 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
596 global scope.
597 Symbols with "<tt>common</tt>" linkage are merged in the same way as
598 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]599 <tt>common</tt> symbols may not have an explicit section,
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]600 must have a zero initializer, and may not be marked '<a
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]601 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
602 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]604
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]605 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]606 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]607 pointer to array type. When two global variables with appending linkage
608 are linked together, the two global arrays are appended together. This is
609 the LLVM, typesafe, equivalent of having the system linker append together
610 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]611
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]612 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]613 <dd>The semantics of this linkage follow the ELF object file model: the symbol
614 is weak until linked, if not linked, the symbol becomes null instead of
615 being an undefined reference.</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_linkonce_odr">linkonce_odr</a></b></tt></dt>
618 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]619 <dd>Some languages allow differing globals to be merged, such as two functions
620 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendlingf8239662010-07-01 21:55:59 +0000[diff] [blame]621 that only equivalent globals are ever merged (the "one definition rule"
622 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]623 and <tt>weak_odr</tt> linkage types to indicate that the global will only
624 be merged with equivalent globals. These linkage types are otherwise the
625 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]626
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]627 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]628 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]629 visible, meaning that it participates in linkage and can be used to
630 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]631</dl>
632
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]633<p>The next two types of linkage are targeted for Microsoft Windows platform
634 only. They are designed to support importing (exporting) symbols from (to)
635 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]636
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]637<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]639 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]640 or variable via a global pointer to a pointer that is set up by the DLL
641 exporting the symbol. On Microsoft Windows targets, the pointer name is
642 formed by combining <code>__imp_</code> and the function or variable
643 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]644
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]645 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]646 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]647 pointer to a pointer in a DLL, so that it can be referenced with the
648 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
649 name is formed by combining <code>__imp_</code> and the function or
650 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]651</dl>
652
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]653<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
654 another module defined a "<tt>.LC0</tt>" variable and was linked with this
655 one, one of the two would be renamed, preventing a collision. Since
656 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
657 declarations), they are accessible outside of the current module.</p>
658
659<p>It is illegal for a function <i>declaration</i> to have any linkage type
660 other than "externally visible", <tt>dllimport</tt>
661 or <tt>extern_weak</tt>.</p>
662
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]663<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]664 or <tt>weak_odr</tt> linkages.</p>
665
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]666</div>
667
668<!-- ======================================================================= -->
669<div class="doc_subsection">
670 <a name="callingconv">Calling Conventions</a>
671</div>
672
673<div class="doc_text">
674
675<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]676 and <a href="#i_invoke">invokes</a> can all have an optional calling
677 convention specified for the call. The calling convention of any pair of
678 dynamic caller/callee must match, or the behavior of the program is
679 undefined. The following calling conventions are supported by LLVM, and more
680 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]681
682<dl>
683 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]684 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]685 specified) matches the target C calling conventions. This calling
686 convention supports varargs function calls and tolerates some mismatch in
687 the declared prototype and implemented declaration of the function (as
688 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]689
690 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]691 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]692 (e.g. by passing things in registers). This calling convention allows the
693 target to use whatever tricks it wants to produce fast code for the
694 target, without having to conform to an externally specified ABI
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]695 (Application Binary Interface).
696 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnerac9a9392010-03-11 00:22:57 +0000[diff] [blame]697 when this or the GHC convention is used.</a> This calling convention
698 does not support varargs and requires the prototype of all callees to
699 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]700
701 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]702 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]703 as possible under the assumption that the call is not commonly executed.
704 As such, these calls often preserve all registers so that the call does
705 not break any live ranges in the caller side. This calling convention
706 does not support varargs and requires the prototype of all callees to
707 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]708
Chris Lattnerac9a9392010-03-11 00:22:57 +0000[diff] [blame]709 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
710 <dd>This calling convention has been implemented specifically for use by the
711 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
712 It passes everything in registers, going to extremes to achieve this by
713 disabling callee save registers. This calling convention should not be
714 used lightly but only for specific situations such as an alternative to
715 the <em>register pinning</em> performance technique often used when
716 implementing functional programming languages.At the moment only X86
717 supports this convention and it has the following limitations:
718 <ul>
719 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
720 floating point types are supported.</li>
721 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
722 6 floating point parameters.</li>
723 </ul>
724 This calling convention supports
725 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
726 requires both the caller and callee are using it.
727 </dd>
728
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]729 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]730 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]731 target-specific calling conventions to be used. Target specific calling
732 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]733</dl>
734
735<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]736 support Pascal conventions or any other well-known target-independent
737 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]738
739</div>
740
741<!-- ======================================================================= -->
742<div class="doc_subsection">
743 <a name="visibility">Visibility Styles</a>
744</div>
745
746<div class="doc_text">
747
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]748<p>All Global Variables and Functions have one of the following visibility
749 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]750
751<dl>
752 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]753 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]754 that the declaration is visible to other modules and, in shared libraries,
755 means that the declared entity may be overridden. On Darwin, default
756 visibility means that the declaration is visible to other modules. Default
757 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]758
759 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]760 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]761 object if they are in the same shared object. Usually, hidden visibility
762 indicates that the symbol will not be placed into the dynamic symbol
763 table, so no other module (executable or shared library) can reference it
764 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]765
766 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]767 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]768 the dynamic symbol table, but that references within the defining module
769 will bind to the local symbol. That is, the symbol cannot be overridden by
770 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]771</dl>
772
773</div>
774
775<!-- ======================================================================= -->
776<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]777 <a name="namedtypes">Named Types</a>
778</div>
779
780<div class="doc_text">
781
782<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]783 it easier to read the IR and make the IR more condensed (particularly when
784 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]785
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]786<pre class="doc_code">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]787%mytype = type { %mytype*, i32 }
788</pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]789
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]790<p>You may give a name to any <a href="#typesystem">type</a> except
791 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
792 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]793
794<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]795 and that you can therefore specify multiple names for the same type. This
796 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
797 uses structural typing, the name is not part of the type. When printing out
798 LLVM IR, the printer will pick <em>one name</em> to render all types of a
799 particular shape. This means that if you have code where two different
800 source types end up having the same LLVM type, that the dumper will sometimes
801 print the "wrong" or unexpected type. This is an important design point and
802 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]803
804</div>
805
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]806<!-- ======================================================================= -->
807<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]808 <a name="globalvars">Global Variables</a>
809</div>
810
811<div class="doc_text">
812
813<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]814 instead of run-time. Global variables may optionally be initialized, may
815 have an explicit section to be placed in, and may have an optional explicit
816 alignment specified. A variable may be defined as "thread_local", which
817 means that it will not be shared by threads (each thread will have a
818 separated copy of the variable). A variable may be defined as a global
819 "constant," which indicates that the contents of the variable
820 will <b>never</b> be modified (enabling better optimization, allowing the
821 global data to be placed in the read-only section of an executable, etc).
822 Note that variables that need runtime initialization cannot be marked
823 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]824
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]825<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
826 constant, even if the final definition of the global is not. This capability
827 can be used to enable slightly better optimization of the program, but
828 requires the language definition to guarantee that optimizations based on the
829 'constantness' are valid for the translation units that do not include the
830 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]831
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]832<p>As SSA values, global variables define pointer values that are in scope
833 (i.e. they dominate) all basic blocks in the program. Global variables
834 always define a pointer to their "content" type because they describe a
835 region of memory, and all memory objects in LLVM are accessed through
836 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]837
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]838<p>A global variable may be declared to reside in a target-specific numbered
839 address space. For targets that support them, address spaces may affect how
840 optimizations are performed and/or what target instructions are used to
841 access the variable. The default address space is zero. The address space
842 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]843
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]844<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]845 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]846
Chris Lattner72413b22010-04-28 00:13:42 +0000[diff] [blame]847<p>An explicit alignment may be specified for a global, which must be a power
848 of 2. If not present, or if the alignment is set to zero, the alignment of
849 the global is set by the target to whatever it feels convenient. If an
850 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner50d07d02010-04-28 00:31:12 +0000[diff] [blame]851 alignment. Targets and optimizers are not allowed to over-align the global
852 if the global has an assigned section. In this case, the extra alignment
853 could be observable: for example, code could assume that the globals are
854 densely packed in their section and try to iterate over them as an array,
855 alignment padding would break this iteration.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]856
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]857<p>For example, the following defines a global in a numbered address space with
858 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]859
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]860<pre class="doc_code">
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]861@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]862</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]863
864</div>
865
866
867<!-- ======================================================================= -->
868<div class="doc_subsection">
869 <a name="functionstructure">Functions</a>
870</div>
871
872<div class="doc_text">
873
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]874<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]875 optional <a href="#linkage">linkage type</a>, an optional
876 <a href="#visibility">visibility style</a>, an optional
877 <a href="#callingconv">calling convention</a>, a return type, an optional
878 <a href="#paramattrs">parameter attribute</a> for the return type, a function
879 name, a (possibly empty) argument list (each with optional
880 <a href="#paramattrs">parameter attributes</a>), optional
881 <a href="#fnattrs">function attributes</a>, an optional section, an optional
882 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
883 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]884
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]885<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
886 optional <a href="#linkage">linkage type</a>, an optional
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]887 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]888 <a href="#callingconv">calling convention</a>, a return type, an optional
889 <a href="#paramattrs">parameter attribute</a> for the return type, a function
890 name, a possibly empty list of arguments, an optional alignment, and an
891 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]892
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]893<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]894 (Control Flow Graph) for the function. Each basic block may optionally start
895 with a label (giving the basic block a symbol table entry), contains a list
896 of instructions, and ends with a <a href="#terminators">terminator</a>
897 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]898
899<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]900 executed on entrance to the function, and it is not allowed to have
901 predecessor basic blocks (i.e. there can not be any branches to the entry
902 block of a function). Because the block can have no predecessors, it also
903 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]904
905<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]906 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]907
908<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]909 the alignment is set to zero, the alignment of the function is set by the
910 target to whatever it feels convenient. If an explicit alignment is
911 specified, the function is forced to have at least that much alignment. All
912 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]913
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]914<h5>Syntax:</h5>
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]915<pre class="doc_code">
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]916define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]917 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
918 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
919 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
920 [<a href="#gc">gc</a>] { ... }
921</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]922
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]923</div>
924
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]925<!-- ======================================================================= -->
926<div class="doc_subsection">
927 <a name="aliasstructure">Aliases</a>
928</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]929
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]930<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]931
932<p>Aliases act as "second name" for the aliasee value (which can be either
933 function, global variable, another alias or bitcast of global value). Aliases
934 may have an optional <a href="#linkage">linkage type</a>, and an
935 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]936
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]937<h5>Syntax:</h5>
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]938<pre class="doc_code">
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]939@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]940</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]941
942</div>
943
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]944<!-- ======================================================================= -->
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]945<div class="doc_subsection">
946 <a name="namedmetadatastructure">Named Metadata</a>
947</div>
948
949<div class="doc_text">
950
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]951<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman94e59a02010-07-21 18:54:18 +0000[diff] [blame^]952 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]953 a named metadata.</p>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]954
955<h5>Syntax:</h5>
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]956<pre class="doc_code">
Dan Gohman94e59a02010-07-21 18:54:18 +0000[diff] [blame^]957; Some unnamed metadata nodes, which are referenced by the named metadata.
958!0 = metadata !{metadata !"zero"}
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]959!1 = metadata !{metadata !"one"}
Dan Gohman94e59a02010-07-21 18:54:18 +0000[diff] [blame^]960!2 = metadata !{metadata !"two"}
Dan Gohmanc9e14412010-07-13 19:48:13 +0000[diff] [blame]961; A named metadata.
Dan Gohman94e59a02010-07-21 18:54:18 +0000[diff] [blame^]962!name = !{!0, !1, !2}
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]963</pre>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]964
965</div>
966
967<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]968<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]969
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]970<div class="doc_text">
971
972<p>The return type and each parameter of a function type may have a set of
973 <i>parameter attributes</i> associated with them. Parameter attributes are
974 used to communicate additional information about the result or parameters of
975 a function. Parameter attributes are considered to be part of the function,
976 not of the function type, so functions with different parameter attributes
977 can have the same function type.</p>
978
979<p>Parameter attributes are simple keywords that follow the type specified. If
980 multiple parameter attributes are needed, they are space separated. For
981 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]982
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]983<pre class="doc_code">
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]984declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]985declare i32 @atoi(i8 zeroext)
986declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]987</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]988
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]989<p>Note that any attributes for the function result (<tt>nounwind</tt>,
990 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]991
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]992<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]993
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]994<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]995 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]996 <dd>This indicates to the code generator that the parameter or return value
997 should be zero-extended to a 32-bit value by the caller (for a parameter)
998 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]999
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1000 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1001 <dd>This indicates to the code generator that the parameter or return value
1002 should be sign-extended to a 32-bit value by the caller (for a parameter)
1003 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1004
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1005 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1006 <dd>This indicates that this parameter or return value should be treated in a
1007 special target-dependent fashion during while emitting code for a function
1008 call or return (usually, by putting it in a register as opposed to memory,
1009 though some targets use it to distinguish between two different kinds of
1010 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1011
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1012 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1013 <dd>This indicates that the pointer parameter should really be passed by value
1014 to the function. The attribute implies that a hidden copy of the pointee
1015 is made between the caller and the callee, so the callee is unable to
1016 modify the value in the callee. This attribute is only valid on LLVM
1017 pointer arguments. It is generally used to pass structs and arrays by
1018 value, but is also valid on pointers to scalars. The copy is considered
1019 to belong to the caller not the callee (for example,
1020 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1021 <tt>byval</tt> parameters). This is not a valid attribute for return
1022 values. The byval attribute also supports specifying an alignment with
1023 the align attribute. This has a target-specific effect on the code
1024 generator that usually indicates a desired alignment for the synthesized
1025 stack slot.</dd>
1026
Dan Gohmanbd2f9ba2010-07-02 23:18:08 +0000[diff] [blame]1027 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1028 <dd>This indicates that the pointer parameter specifies the address of a
1029 structure that is the return value of the function in the source program.
1030 This pointer must be guaranteed by the caller to be valid: loads and
1031 stores to the structure may be assumed by the callee to not to trap. This
1032 may only be applied to the first parameter. This is not a valid attribute
1033 for return values. </dd>
1034
Dan Gohmanbd2f9ba2010-07-02 23:18:08 +0000[diff] [blame]1035 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmanc8208442010-07-02 18:41:32 +0000[diff] [blame]1036 <dd>This indicates that pointer values
1037 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohman24fc36d2010-07-02 23:46:54 +0000[diff] [blame]1038 value do not alias pointer values which are not <i>based</i> on it,
1039 ignoring certain "irrelevant" dependencies.
1040 For a call to the parent function, dependencies between memory
1041 references from before or after the call and from those during the call
1042 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1043 return value used in that call.
Dan Gohmanc8208442010-07-02 18:41:32 +0000[diff] [blame]1044 The caller shares the responsibility with the callee for ensuring that
1045 these requirements are met.
1046 For further details, please see the discussion of the NoAlias response in
Dan Gohman8c6704c2010-07-06 15:26:33 +0000[diff] [blame]1047 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1048<br>
John McCall0f56d702010-07-06 21:07:14 +0000[diff] [blame]1049 Note that this definition of <tt>noalias</tt> is intentionally
1050 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattnerd6c58d82010-07-06 20:51:35 +0000[diff] [blame]1051 arguments, though it is slightly weaker.
Dan Gohman8c6704c2010-07-06 15:26:33 +0000[diff] [blame]1052<br>
1053 For function return values, C99's <tt>restrict</tt> is not meaningful,
1054 while LLVM's <tt>noalias</tt> is.
1055 </dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1056
Dan Gohmanbd2f9ba2010-07-02 23:18:08 +0000[diff] [blame]1057 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1058 <dd>This indicates that the callee does not make any copies of the pointer
1059 that outlive the callee itself. This is not a valid attribute for return
1060 values.</dd>
1061
Dan Gohmanbd2f9ba2010-07-02 23:18:08 +0000[diff] [blame]1062 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1063 <dd>This indicates that the pointer parameter can be excised using the
1064 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1065 attribute for return values.</dd>
1066</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1067
1068</div>
1069
1070<!-- ======================================================================= -->
1071<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1072 <a name="gc">Garbage Collector Names</a>
1073</div>
1074
1075<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1076
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1077<p>Each function may specify a garbage collector name, which is simply a
1078 string:</p>
1079
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]1080<pre class="doc_code">
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1081define void @f() gc "name" { ... }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1082</pre>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1083
1084<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1085 collector which will cause the compiler to alter its output in order to
1086 support the named garbage collection algorithm.</p>
1087
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1088</div>
1089
1090<!-- ======================================================================= -->
1091<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1092 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1093</div>
1094
1095<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1096
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1097<p>Function attributes are set to communicate additional information about a
1098 function. Function attributes are considered to be part of the function, not
1099 of the function type, so functions with different parameter attributes can
1100 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1101
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1102<p>Function attributes are simple keywords that follow the type specified. If
1103 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1104
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]1105<pre class="doc_code">
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
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1112<dl>
Charles Davisfaa8f752010-02-12 00:31:15 +0000[diff] [blame]1113 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1114 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1115 the backend should forcibly align the stack pointer. Specify the
1116 desired alignment, which must be a power of two, in parentheses.
1117
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1118 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1119 <dd>This attribute indicates that the inliner should attempt to inline this
1120 function into callers whenever possible, ignoring any active inlining size
1121 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1122
Jakob Stoklund Olesen77180732010-02-06 01:16:28 +0000[diff] [blame]1123 <dt><tt><b>inlinehint</b></tt></dt>
1124 <dd>This attribute indicates that the source code contained a hint that inlining
1125 this function is desirable (such as the "inline" keyword in C/C++). It
1126 is just a hint; it imposes no requirements on the inliner.</dd>
1127
Nick Lewyckybc036ee2010-07-06 18:24:09 +0000[diff] [blame]1128 <dt><tt><b>naked</b></tt></dt>
1129 <dd>This attribute disables prologue / epilogue emission for the function.
1130 This can have very system-specific consequences.</dd>
1131
1132 <dt><tt><b>noimplicitfloat</b></tt></dt>
1133 <dd>This attributes disables implicit floating point instructions.</dd>
1134
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1135 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1136 <dd>This attribute indicates that the inliner should never inline this
1137 function in any situation. This attribute may not be used together with
1138 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1139
Nick Lewyckybc036ee2010-07-06 18:24:09 +0000[diff] [blame]1140 <dt><tt><b>noredzone</b></tt></dt>
1141 <dd>This attribute indicates that the code generator should not use a red
1142 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1143
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1144 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1145 <dd>This function attribute indicates that the function never returns
1146 normally. This produces undefined behavior at runtime if the function
1147 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1148
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1149 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1150 <dd>This function attribute indicates that the function never returns with an
1151 unwind or exceptional control flow. If the function does unwind, its
1152 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1153
Nick Lewyckybc036ee2010-07-06 18:24:09 +0000[diff] [blame]1154 <dt><tt><b>optsize</b></tt></dt>
1155 <dd>This attribute suggests that optimization passes and code generator passes
1156 make choices that keep the code size of this function low, and otherwise
1157 do optimizations specifically to reduce code size.</dd>
1158
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1159 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1160 <dd>This attribute indicates that the function computes its result (or decides
1161 to unwind an exception) based strictly on its arguments, without
1162 dereferencing any pointer arguments or otherwise accessing any mutable
1163 state (e.g. memory, control registers, etc) visible to caller functions.
1164 It does not write through any pointer arguments
1165 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1166 changes any state visible to callers. This means that it cannot unwind
1167 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1168 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1169
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1170 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1171 <dd>This attribute indicates that the function does not write through any
1172 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1173 arguments) or otherwise modify any state (e.g. memory, control registers,
1174 etc) visible to caller functions. It may dereference pointer arguments
1175 and read state that may be set in the caller. A readonly function always
1176 returns the same value (or unwinds an exception identically) when called
1177 with the same set of arguments and global state. It cannot unwind an
1178 exception by calling the <tt>C++</tt> exception throwing methods, but may
1179 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1180
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1181 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1182 <dd>This attribute indicates that the function should emit a stack smashing
1183 protector. It is in the form of a "canary"&mdash;a random value placed on
1184 the stack before the local variables that's checked upon return from the
1185 function to see if it has been overwritten. A heuristic is used to
1186 determine if a function needs stack protectors or not.<br>
1187<br>
1188 If a function that has an <tt>ssp</tt> attribute is inlined into a
1189 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1190 function will have an <tt>ssp</tt> attribute.</dd>
1191
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1192 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1193 <dd>This attribute indicates that the function should <em>always</em> emit a
1194 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1195 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1196<br>
1197 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1198 function that doesn't have an <tt>sspreq</tt> attribute or which has
1199 an <tt>ssp</tt> attribute, then the resulting function will have
1200 an <tt>sspreq</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1201</dl>
1202
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1203</div>
1204
1205<!-- ======================================================================= -->
1206<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1207 <a name="moduleasm">Module-Level Inline Assembly</a>
1208</div>
1209
1210<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1211
1212<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1213 the GCC "file scope inline asm" blocks. These blocks are internally
1214 concatenated by LLVM and treated as a single unit, but may be separated in
1215 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1216
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]1217<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1218module asm "inline asm code goes here"
1219module asm "more can go here"
1220</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1221
1222<p>The strings can contain any character by escaping non-printable characters.
1223 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]1224 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1225
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1226<p>The inline asm code is simply printed to the machine code .s file when
1227 assembly code is generated.</p>
1228
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1229</div>
1230
1231<!-- ======================================================================= -->
1232<div class="doc_subsection">
1233 <a name="datalayout">Data Layout</a>
1234</div>
1235
1236<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1238<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1239 data is to be laid out in memory. The syntax for the data layout is
1240 simply:</p>
1241
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]1242<pre class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1243target datalayout = "<i>layout specification</i>"
1244</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1245
1246<p>The <i>layout specification</i> consists of a list of specifications
1247 separated by the minus sign character ('-'). Each specification starts with
1248 a letter and may include other information after the letter to define some
1249 aspect of the data layout. The specifications accepted are as follows:</p>
1250
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1251<dl>
1252 <dt><tt>E</tt></dt>
1253 <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]1254 bits with the most significance have the lowest address location.</dd>
1255
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1256 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1257 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1258 the bits with the least significance have the lowest address
1259 location.</dd>
1260
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1261 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1262 <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]1263 <i>preferred</i> alignments. All sizes are in bits. Specifying
1264 the <i>pref</i> alignment is optional. If omitted, the
1265 preceding <tt>:</tt> should be omitted too.</dd>
1266
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1267 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1268 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1269 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1270
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1271 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1272 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1273 <i>size</i>.</dd>
1274
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1275 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1276 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen7dabc4c2010-05-28 18:54:47 +0000[diff] [blame]1277 <i>size</i>. Only values of <i>size</i> that are supported by the target
1278 will work. 32 (float) and 64 (double) are supported on all targets;
1279 80 or 128 (different flavors of long double) are also supported on some
1280 targets.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1281
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1282 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1283 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1284 <i>size</i>.</dd>
1285
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1286 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1287 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1288 <i>size</i>.</dd>
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1289
1290 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1291 <dd>This specifies a set of native integer widths for the target CPU
1292 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1293 "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]1294 this set are considered to support most general arithmetic
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1295 operations efficiently.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1296</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1298<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohmanfde3cd72010-04-28 00:36:01 +0000[diff] [blame]1299 default set of specifications which are then (possibly) overridden by the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1300 specifications in the <tt>datalayout</tt> keyword. The default specifications
1301 are given in this list:</p>
1302
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1303<ul>
1304 <li><tt>E</tt> - big endian</li>
Dan Gohmane78194f2010-02-23 02:44:03 +0000[diff] [blame]1305 <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]1306 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1307 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1308 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1309 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1310 <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]1311 alignment of 64-bits</li>
1312 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1313 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1314 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1315 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1316 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1317 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1318</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1319
1320<p>When LLVM is determining the alignment for a given type, it uses the
1321 following rules:</p>
1322
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1323<ol>
1324 <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]1325 specification is used.</li>
1326
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1327 <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]1328 smallest integer type that is larger than the bitwidth of the sought type
1329 is used. If none of the specifications are larger than the bitwidth then
1330 the the largest integer type is used. For example, given the default
1331 specifications above, the i7 type will use the alignment of i8 (next
1332 largest) while both i65 and i256 will use the alignment of i64 (largest
1333 specified).</li>
1334
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1335 <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]1336 largest vector type that is smaller than the sought vector type will be
1337 used as a fall back. This happens because &lt;128 x double&gt; can be
1338 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1339</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1340
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1341</div>
1342
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1343<!-- ======================================================================= -->
1344<div class="doc_subsection">
1345 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1346</div>
1347
1348<div class="doc_text">
1349
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1350<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1351with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1352is undefined. Pointer values are associated with address ranges
1353according to the following rules:</p>
1354
1355<ul>
Dan Gohmanc8208442010-07-02 18:41:32 +0000[diff] [blame]1356 <li>A pointer value is associated with the addresses associated with
1357 any value it is <i>based</i> on.
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1358 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1359 range of the variable's storage.</li>
1360 <li>The result value of an allocation instruction is associated with
1361 the address range of the allocated storage.</li>
1362 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1363 no address.</li>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1364 <li>An integer constant other than zero or a pointer value returned
1365 from a function not defined within LLVM may be associated with address
1366 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1367 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1368 allocated by mechanisms provided by LLVM.</li>
Dan Gohmanc8208442010-07-02 18:41:32 +0000[diff] [blame]1369</ul>
1370
1371<p>A pointer value is <i>based</i> on another pointer value according
1372 to the following rules:</p>
1373
1374<ul>
1375 <li>A pointer value formed from a
1376 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1377 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1378 <li>The result value of a
1379 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1380 of the <tt>bitcast</tt>.</li>
1381 <li>A pointer value formed by an
1382 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1383 pointer values that contribute (directly or indirectly) to the
1384 computation of the pointer's value.</li>
1385 <li>The "<i>based</i> on" relationship is transitive.</li>
1386</ul>
1387
1388<p>Note that this definition of <i>"based"</i> is intentionally
1389 similar to the definition of <i>"based"</i> in C99, though it is
1390 slightly weaker.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1391
1392<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1393<tt><a href="#i_load">load</a></tt> merely indicates the size and
1394alignment of the memory from which to load, as well as the
Dan Gohmand72730e2010-06-17 19:23:50 +0000[diff] [blame]1395interpretation of the value. The first operand type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1396<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1397and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1398
1399<p>Consequently, type-based alias analysis, aka TBAA, aka
1400<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1401LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1402additional information which specialized optimization passes may use
1403to implement type-based alias analysis.</p>
1404
1405</div>
1406
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]1407<!-- ======================================================================= -->
1408<div class="doc_subsection">
1409 <a name="volatile">Volatile Memory Accesses</a>
1410</div>
1411
1412<div class="doc_text">
1413
1414<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1415href="#i_store"><tt>store</tt></a>s, and <a
1416href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1417The optimizers must not change the number of volatile operations or change their
1418order of execution relative to other volatile operations. The optimizers
1419<i>may</i> change the order of volatile operations relative to non-volatile
1420operations. This is not Java's "volatile" and has no cross-thread
1421synchronization behavior.</p>
1422
1423</div>
1424
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1425<!-- *********************************************************************** -->
1426<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1427<!-- *********************************************************************** -->
1428
1429<div class="doc_text">
1430
1431<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1432 intermediate representation. Being typed enables a number of optimizations
1433 to be performed on the intermediate representation directly, without having
1434 to do extra analyses on the side before the transformation. A strong type
1435 system makes it easier to read the generated code and enables novel analyses
1436 and transformations that are not feasible to perform on normal three address
1437 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1438
1439</div>
1440
1441<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1442<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1443Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1444
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1445<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1446
1447<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1448
1449<table border="1" cellspacing="0" cellpadding="4">
1450 <tbody>
1451 <tr><th>Classification</th><th>Types</th></tr>
1452 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1453 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1454 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1455 </tr>
1456 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1457 <td><a href="#t_floating">floating point</a></td>
1458 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1459 </tr>
1460 <tr>
1461 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1462 <td><a href="#t_integer">integer</a>,
1463 <a href="#t_floating">floating point</a>,
1464 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1465 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1466 <a href="#t_struct">structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1467 <a href="#t_union">union</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1468 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1469 <a href="#t_label">label</a>,
1470 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1471 </td>
1472 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1473 <tr>
1474 <td><a href="#t_primitive">primitive</a></td>
1475 <td><a href="#t_label">label</a>,
1476 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1477 <a href="#t_floating">floating point</a>,
1478 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1479 </tr>
1480 <tr>
1481 <td><a href="#t_derived">derived</a></td>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1482 <td><a href="#t_array">array</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1483 <a href="#t_function">function</a>,
1484 <a href="#t_pointer">pointer</a>,
1485 <a href="#t_struct">structure</a>,
1486 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1487 <a href="#t_union">union</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1488 <a href="#t_vector">vector</a>,
1489 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1490 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1491 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1492 </tbody>
1493</table>
1494
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1495<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1496 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1497 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1498
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1499</div>
1500
1501<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1502<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1503
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1504<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1505
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1506<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1507 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1508
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1509</div>
1510
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1511<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1512<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1513
1514<div class="doc_text">
1515
1516<h5>Overview:</h5>
1517<p>The integer type is a very simple type that simply specifies an arbitrary
1518 bit width for the integer type desired. Any bit width from 1 bit to
1519 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1520
1521<h5>Syntax:</h5>
1522<pre>
1523 iN
1524</pre>
1525
1526<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1527 value.</p>
1528
1529<h5>Examples:</h5>
1530<table class="layout">
1531 <tr class="layout">
1532 <td class="left"><tt>i1</tt></td>
1533 <td class="left">a single-bit integer.</td>
1534 </tr>
1535 <tr class="layout">
1536 <td class="left"><tt>i32</tt></td>
1537 <td class="left">a 32-bit integer.</td>
1538 </tr>
1539 <tr class="layout">
1540 <td class="left"><tt>i1942652</tt></td>
1541 <td class="left">a really big integer of over 1 million bits.</td>
1542 </tr>
1543</table>
1544
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1545</div>
1546
1547<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1548<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1549
1550<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1551
1552<table>
1553 <tbody>
1554 <tr><th>Type</th><th>Description</th></tr>
1555 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1556 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1557 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1558 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1559 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1560 </tbody>
1561</table>
1562
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1563</div>
1564
1565<!-- _______________________________________________________________________ -->
1566<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1567
1568<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1569
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1570<h5>Overview:</h5>
1571<p>The void type does not represent any value and has no size.</p>
1572
1573<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1574<pre>
1575 void
1576</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1577
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1578</div>
1579
1580<!-- _______________________________________________________________________ -->
1581<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1582
1583<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1584
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1585<h5>Overview:</h5>
1586<p>The label type represents code labels.</p>
1587
1588<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1589<pre>
1590 label
1591</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1592
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1593</div>
1594
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1595<!-- _______________________________________________________________________ -->
1596<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1597
1598<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1599
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1600<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1601<p>The metadata type represents embedded metadata. No derived types may be
1602 created from metadata except for <a href="#t_function">function</a>
1603 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1604
1605<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1606<pre>
1607 metadata
1608</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1609
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1610</div>
1611
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1612
1613<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1614<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1615
1616<div class="doc_text">
1617
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1618<p>The real power in LLVM comes from the derived types in the system. This is
1619 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1620 useful types. Each of these types contain one or more element types which
1621 may be a primitive type, or another derived type. For example, it is
1622 possible to have a two dimensional array, using an array as the element type
1623 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1624
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1625
1626</div>
1627
1628<!-- _______________________________________________________________________ -->
1629<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1630
1631<div class="doc_text">
1632
1633<p>Aggregate Types are a subset of derived types that can contain multiple
1634 member types. <a href="#t_array">Arrays</a>,
1635 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1636 <a href="#t_union">unions</a> are aggregate types.</p>
1637
1638</div>
1639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1640<!-- _______________________________________________________________________ -->
1641<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1642
1643<div class="doc_text">
1644
1645<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1646<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1647 sequentially in memory. The array type requires a size (number of elements)
1648 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1649
1650<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1651<pre>
1652 [&lt;# elements&gt; x &lt;elementtype&gt;]
1653</pre>
1654
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1655<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1656 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1657
1658<h5>Examples:</h5>
1659<table class="layout">
1660 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1661 <td class="left"><tt>[40 x i32]</tt></td>
1662 <td class="left">Array of 40 32-bit integer values.</td>
1663 </tr>
1664 <tr class="layout">
1665 <td class="left"><tt>[41 x i32]</tt></td>
1666 <td class="left">Array of 41 32-bit integer values.</td>
1667 </tr>
1668 <tr class="layout">
1669 <td class="left"><tt>[4 x i8]</tt></td>
1670 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1671 </tr>
1672</table>
1673<p>Here are some examples of multidimensional arrays:</p>
1674<table class="layout">
1675 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1676 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1677 <td class="left">3x4 array of 32-bit integer values.</td>
1678 </tr>
1679 <tr class="layout">
1680 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1681 <td class="left">12x10 array of single precision floating point values.</td>
1682 </tr>
1683 <tr class="layout">
1684 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1685 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1686 </tr>
1687</table>
1688
Dan Gohman87ec5ad2009-11-09 19:01:53 +0000[diff] [blame]1689<p>There is no restriction on indexing beyond the end of the array implied by
1690 a static type (though there are restrictions on indexing beyond the bounds
1691 of an allocated object in some cases). This means that single-dimension
1692 'variable sized array' addressing can be implemented in LLVM with a zero
1693 length array type. An implementation of 'pascal style arrays' in LLVM could
1694 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1695
1696</div>
1697
1698<!-- _______________________________________________________________________ -->
1699<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1700
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1701<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1702
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1703<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1704<p>The function type can be thought of as a function signature. It consists of
1705 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]1706 function type is a scalar type, a void type, a struct type, or a union
1707 type. If the return type is a struct type then all struct elements must be
1708 of first class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1709
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1710<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1711<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1712 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1713</pre>
1714
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1715<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]1716 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1717 which indicates that the function takes a variable number of arguments.
1718 Variable argument functions can access their arguments with
1719 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1720 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1721 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1722
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1723<h5>Examples:</h5>
1724<table class="layout">
1725 <tr class="layout">
1726 <td class="left"><tt>i32 (i32)</tt></td>
1727 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1728 </td>
1729 </tr><tr class="layout">
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1730 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1731 </tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1732 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1733 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1734 returning <tt>float</tt>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1735 </td>
1736 </tr><tr class="layout">
1737 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1738 <td class="left">A vararg function that takes at least one
1739 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1740 which returns an integer. This is the signature for <tt>printf</tt> in
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1741 LLVM.
1742 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1743 </tr><tr class="layout">
1744 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1745 <td class="left">A function taking an <tt>i32</tt>, returning a
1746 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1747 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1748 </tr>
1749</table>
1750
1751</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1752
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1753<!-- _______________________________________________________________________ -->
1754<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1755
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1756<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1757
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1758<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1759<p>The structure type is used to represent a collection of data members together
1760 in memory. The packing of the field types is defined to match the ABI of the
1761 underlying processor. The elements of a structure may be any type that has a
1762 size.</p>
1763
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]1764<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1765 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1766 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1767 Structures in registers are accessed using the
1768 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1769 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1770<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1771<pre>
1772 { &lt;type list&gt; }
1773</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1774
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1775<h5>Examples:</h5>
1776<table class="layout">
1777 <tr class="layout">
1778 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1779 <td class="left">A triple of three <tt>i32</tt> values</td>
1780 </tr><tr class="layout">
1781 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1782 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1783 second element is a <a href="#t_pointer">pointer</a> to a
1784 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1785 an <tt>i32</tt>.</td>
1786 </tr>
1787</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1788
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1789</div>
1790
1791<!-- _______________________________________________________________________ -->
1792<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1793</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1794
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1795<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1796
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1797<h5>Overview:</h5>
1798<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1799 together in memory. There is no padding between fields. Further, the
1800 alignment of a packed structure is 1 byte. The elements of a packed
1801 structure may be any type that has a size.</p>
1802
1803<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1804 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1805 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1806
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1807<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1808<pre>
1809 &lt; { &lt;type list&gt; } &gt;
1810</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1811
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1812<h5>Examples:</h5>
1813<table class="layout">
1814 <tr class="layout">
1815 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1816 <td class="left">A triple of three <tt>i32</tt> values</td>
1817 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1818 <td class="left">
1819<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1820 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1821 second element is a <a href="#t_pointer">pointer</a> to a
1822 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1823 an <tt>i32</tt>.</td>
1824 </tr>
1825</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1826
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1827</div>
1828
1829<!-- _______________________________________________________________________ -->
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1830<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1831
1832<div class="doc_text">
1833
1834<h5>Overview:</h5>
1835<p>A union type describes an object with size and alignment suitable for
1836 an object of any one of a given set of types (also known as an "untagged"
1837 union). It is similar in concept and usage to a
1838 <a href="#t_struct">struct</a>, except that all members of the union
1839 have an offset of zero. The elements of a union may be any type that has a
1840 size. Unions must have at least one member - empty unions are not allowed.
1841 </p>
1842
1843<p>The size of the union as a whole will be the size of its largest member,
1844 and the alignment requirements of the union as a whole will be the largest
1845 alignment requirement of any member.</p>
1846
Dan Gohmanef8400c2010-02-25 16:51:31 +0000[diff] [blame]1847<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]1848 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1849 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1850 Since all members are at offset zero, the getelementptr instruction does
1851 not affect the address, only the type of the resulting pointer.</p>
1852
1853<h5>Syntax:</h5>
1854<pre>
1855 union { &lt;type list&gt; }
1856</pre>
1857
1858<h5>Examples:</h5>
1859<table class="layout">
1860 <tr class="layout">
1861 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1862 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1863 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1864 </tr><tr class="layout">
1865 <td class="left">
1866 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1867 <td class="left">A union, where the first element is a <tt>float</tt> and the
1868 second element is a <a href="#t_pointer">pointer</a> to a
1869 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1870 an <tt>i32</tt>.</td>
1871 </tr>
1872</table>
1873
1874</div>
1875
1876<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1877<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1878
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1879<div class="doc_text">
1880
1881<h5>Overview:</h5>
Dan Gohmanb2f72c82010-02-25 16:50:07 +0000[diff] [blame]1882<p>The pointer type is used to specify memory locations.
1883 Pointers are commonly used to reference objects in memory.</p>
1884
1885<p>Pointer types may have an optional address space attribute defining the
1886 numbered address space where the pointed-to object resides. The default
1887 address space is number zero. The semantics of non-zero address
1888 spaces are target-specific.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1889
1890<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1891 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1892
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1893<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1894<pre>
1895 &lt;type&gt; *
1896</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1897
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1898<h5>Examples:</h5>
1899<table class="layout">
1900 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1901 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1902 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1903 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1904 </tr>
1905 <tr class="layout">
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]1906 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1907 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1908 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1909 <tt>i32</tt>.</td>
1910 </tr>
1911 <tr class="layout">
1912 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1913 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1914 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1915 </tr>
1916</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1917
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1918</div>
1919
1920<!-- _______________________________________________________________________ -->
1921<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1922
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1923<div class="doc_text">
1924
1925<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1926<p>A vector type is a simple derived type that represents a vector of elements.
1927 Vector types are used when multiple primitive data are operated in parallel
1928 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands87598b02009-11-27 13:38:03 +0000[diff] [blame]1929 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1930 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1931
1932<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1933<pre>
1934 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1935</pre>
1936
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1937<p>The number of elements is a constant integer value; elementtype may be any
1938 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1939
1940<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1941<table class="layout">
1942 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1943 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1944 <td class="left">Vector of 4 32-bit integer values.</td>
1945 </tr>
1946 <tr class="layout">
1947 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1948 <td class="left">Vector of 8 32-bit floating-point values.</td>
1949 </tr>
1950 <tr class="layout">
1951 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1952 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1953 </tr>
1954</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1955
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1956</div>
1957
1958<!-- _______________________________________________________________________ -->
1959<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1960<div class="doc_text">
1961
1962<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1963<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1964 corresponds (for example) to the C notion of a forward declared structure
1965 type. In LLVM, opaque types can eventually be resolved to any type (not just
1966 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1967
1968<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1969<pre>
1970 opaque
1971</pre>
1972
1973<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1974<table class="layout">
1975 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1976 <td class="left"><tt>opaque</tt></td>
1977 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1978 </tr>
1979</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1980
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1981</div>
1982
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1983<!-- ======================================================================= -->
1984<div class="doc_subsection">
1985 <a name="t_uprefs">Type Up-references</a>
1986</div>
1987
1988<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1989
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1990<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1991<p>An "up reference" allows you to refer to a lexically enclosing type without
1992 requiring it to have a name. For instance, a structure declaration may
1993 contain a pointer to any of the types it is lexically a member of. Example
1994 of up references (with their equivalent as named type declarations)
1995 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1996
1997<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1998 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1999 { \2 }* %y = type { %y }*
2000 \1* %z = type %z*
2001</pre>
2002
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2003<p>An up reference is needed by the asmprinter for printing out cyclic types
2004 when there is no declared name for a type in the cycle. Because the
2005 asmprinter does not want to print out an infinite type string, it needs a
2006 syntax to handle recursive types that have no names (all names are optional
2007 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2008
2009<h5>Syntax:</h5>
2010<pre>
2011 \&lt;level&gt;
2012</pre>
2013
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2014<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]2015
2016<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2017<table class="layout">
2018 <tr class="layout">
2019 <td class="left"><tt>\1*</tt></td>
2020 <td class="left">Self-referential pointer.</td>
2021 </tr>
2022 <tr class="layout">
2023 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2024 <td class="left">Recursive structure where the upref refers to the out-most
2025 structure.</td>
2026 </tr>
2027</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2028
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2029</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2030
2031<!-- *********************************************************************** -->
2032<div class="doc_section"> <a name="constants">Constants</a> </div>
2033<!-- *********************************************************************** -->
2034
2035<div class="doc_text">
2036
2037<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2038 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2039
2040</div>
2041
2042<!-- ======================================================================= -->
2043<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
2044
2045<div class="doc_text">
2046
2047<dl>
2048 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2049 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]2050 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2051
2052 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2053 <dd>Standard integers (such as '4') are constants of
2054 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2055 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2056
2057 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2058 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2059 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2060 notation (see below). The assembler requires the exact decimal value of a
2061 floating-point constant. For example, the assembler accepts 1.25 but
2062 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2063 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2064
2065 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2066 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2067 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2068</dl>
2069
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2070<p>The one non-intuitive notation for constants is the hexadecimal form of
2071 floating point constants. For example, the form '<tt>double
2072 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2073 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2074 constants are required (and the only time that they are generated by the
2075 disassembler) is when a floating point constant must be emitted but it cannot
2076 be represented as a decimal floating point number in a reasonable number of
2077 digits. For example, NaN's, infinities, and other special values are
2078 represented in their IEEE hexadecimal format so that assembly and disassembly
2079 do not cause any bits to change in the constants.</p>
2080
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]2081<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2082 represented using the 16-digit form shown above (which matches the IEEE754
2083 representation for double); float values must, however, be exactly
2084 representable as IEE754 single precision. Hexadecimal format is always used
2085 for long double, and there are three forms of long double. The 80-bit format
2086 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2087 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2088 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2089 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2090 currently supported target uses this format. Long doubles will only work if
2091 they match the long double format on your target. All hexadecimal formats
2092 are big-endian (sign bit at the left).</p>
2093
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2094</div>
2095
2096<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2097<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2098<a name="aggregateconstants"></a> <!-- old anchor -->
2099<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2100</div>
2101
2102<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2103
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2104<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2105 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2106
2107<dl>
2108 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2109 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2110 type definitions (a comma separated list of elements, surrounded by braces
2111 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2112 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2113 Structure constants must have <a href="#t_struct">structure type</a>, and
2114 the number and types of elements must match those specified by the
2115 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2116
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2117 <dt><b>Union constants</b></dt>
2118 <dd>Union constants are represented with notation similar to a structure with
2119 a single element - that is, a single typed element surrounded
2120 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2121 <a href="#t_union">union type</a> can be initialized with a single-element
2122 struct as long as the type of the struct element matches the type of
2123 one of the union members.</dd>
2124
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2125 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2126 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2127 definitions (a comma separated list of elements, surrounded by square
2128 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2129 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2130 the number and types of elements must match those specified by the
2131 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2132
2133 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2134 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2135 definitions (a comma separated list of elements, surrounded by
2136 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2137 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2138 have <a href="#t_vector">vector type</a>, and the number and types of
2139 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2140
2141 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2142 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2143 value to zero of <em>any</em> type, including scalar and
2144 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2145 This is often used to avoid having to print large zero initializers
2146 (e.g. for large arrays) and is always exactly equivalent to using explicit
2147 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2148
2149 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]2150 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2151 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2152 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2153 be interpreted as part of the instruction stream, metadata is a place to
2154 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2155</dl>
2156
2157</div>
2158
2159<!-- ======================================================================= -->
2160<div class="doc_subsection">
2161 <a name="globalconstants">Global Variable and Function Addresses</a>
2162</div>
2163
2164<div class="doc_text">
2165
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2166<p>The addresses of <a href="#globalvars">global variables</a>
2167 and <a href="#functionstructure">functions</a> are always implicitly valid
2168 (link-time) constants. These constants are explicitly referenced when
2169 the <a href="#identifiers">identifier for the global</a> is used and always
2170 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2171 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2172
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2173<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2174@X = global i32 17
2175@Y = global i32 42
2176@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2177</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2178
2179</div>
2180
2181<!-- ======================================================================= -->
2182<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2183<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2184
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2185<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]2186 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2187 Undefined values may be of any type (other than label or void) and be used
2188 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2189
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2190<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2191 program is well defined no matter what value is used. This gives the
2192 compiler more freedom to optimize. Here are some examples of (potentially
2193 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2194
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2195
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2196<pre class="doc_code">
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2197 %A = add %X, undef
2198 %B = sub %X, undef
2199 %C = xor %X, undef
2200Safe:
2201 %A = undef
2202 %B = undef
2203 %C = undef
2204</pre>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2205
2206<p>This is safe because all of the output bits are affected by the undef bits.
2207Any output bit can have a zero or one depending on the input bits.</p>
2208
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2209<pre class="doc_code">
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2210 %A = or %X, undef
2211 %B = and %X, undef
2212Safe:
2213 %A = -1
2214 %B = 0
2215Unsafe:
2216 %A = undef
2217 %B = undef
2218</pre>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2219
2220<p>These logical operations have bits that are not always affected by the input.
2221For example, if "%X" has a zero bit, then the output of the 'and' operation will
2222always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2223such, 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]2224However, it is safe to assume that all bits of the undef could be 0, and
2225optimize the and to 0. Likewise, it is safe to assume that all the bits of
2226the 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]2227-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2228
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2229<pre class="doc_code">
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]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>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2242
2243<p>This set of examples show that undefined select (and conditional branch)
2244conditions can go "either way" but they have to come from one of the two
2245operands. In the %A example, if %X and %Y were both known to have a clear low
2246bit, then %A would have to have a cleared low bit. However, in the %C example,
2247the optimizer is allowed to assume that the undef operand could be the same as
2248%Y, allowing the whole select to be eliminated.</p>
2249
2250
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2251<pre class="doc_code">
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2252 %A = xor undef, undef
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2253
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2254 %B = undef
2255 %C = xor %B, %B
2256
2257 %D = undef
2258 %E = icmp lt %D, 4
2259 %F = icmp gte %D, 4
2260
2261Safe:
2262 %A = undef
2263 %B = undef
2264 %C = undef
2265 %D = undef
2266 %E = undef
2267 %F = undef
2268</pre>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2269
2270<p>This example points out that two undef operands are not necessarily the same.
2271This can be surprising to people (and also matches C semantics) where they
2272assume that "X^X" is always zero, even if X is undef. This isn't true for a
2273number of reasons, but the short answer is that an undef "variable" can
2274arbitrarily change its value over its "live range". This is true because the
2275"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2276logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2277so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2278to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2279would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2280
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2281<pre class="doc_code">
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2282 %A = fdiv undef, %X
2283 %B = fdiv %X, undef
2284Safe:
2285 %A = undef
2286b: unreachable
2287</pre>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2288
2289<p>These examples show the crucial difference between an <em>undefined
2290value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2291allowed to have an arbitrary bit-pattern. This means that the %A operation
2292can be constant folded to undef because the undef could be an SNaN, and fdiv is
2293not (currently) defined on SNaN's. However, in the second example, we can make
2294a more aggressive assumption: because the undef is allowed to be an arbitrary
2295value, 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]2296has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2297does not execute at all. This allows us to delete the divide and all code after
2298it: since the undefined operation "can't happen", the optimizer can assume that
2299it occurs in dead code.
2300</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2301
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2302<pre class="doc_code">
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2303a: store undef -> %X
2304b: store %X -> undef
2305Safe:
2306a: &lt;deleted&gt;
2307b: unreachable
2308</pre>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2309
2310<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2311can be assumed to not have any effect: we can assume that the value is
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2312overwritten with bits that happen to match what was already there. However, a
2313store "to" an undefined location could clobber arbitrary memory, therefore, it
2314has undefined behavior.</p>
2315
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2316</div>
2317
2318<!-- ======================================================================= -->
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2319<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2320<div class="doc_text">
2321
Dan Gohman67bf37f2010-04-26 20:21:21 +0000[diff] [blame]2322<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2323 instead of representing an unspecified bit pattern, they represent the
2324 fact that an instruction or constant expression which cannot evoke side
2325 effects has nevertheless detected a condition which results in undefined
Dan Gohman67bf37f2010-04-26 20:21:21 +0000[diff] [blame]2326 behavior.</p>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2327
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2328<p>There is currently no way of representing a trap value in the IR; they
Dan Gohmanc4bfe502010-05-03 14:51:43 +0000[diff] [blame]2329 only exist when produced by operations such as
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2330 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2331
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2332<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2333
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2334<ul>
2335<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2336 their operands.</li>
2337
2338<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2339 to their dynamic predecessor basic block.</li>
2340
2341<li>Function arguments depend on the corresponding actual argument values in
2342 the dynamic callers of their functions.</li>
2343
2344<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2345 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2346 control back to them.</li>
2347
Dan Gohman5e7b8fb2010-05-03 14:55:22 +0000[diff] [blame]2348<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2349 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2350 or exception-throwing call instructions that dynamically transfer control
2351 back to them.</li>
2352
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2353<li>Non-volatile loads and stores depend on the most recent stores to all of the
2354 referenced memory addresses, following the order in the IR
2355 (including loads and stores implied by intrinsics such as
2356 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2357
Dan Gohmane2c06b62010-05-03 14:59:34 +0000[diff] [blame]2358<!-- TODO: In the case of multiple threads, this only applies if the store
2359 "happens-before" the load or store. -->
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2360
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2361<!-- TODO: floating-point exception state -->
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2362
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2363<li>An instruction with externally visible side effects depends on the most
2364 recent preceding instruction with externally visible side effects, following
Dan Gohman8c6704c2010-07-06 15:26:33 +0000[diff] [blame]2365 the order in the IR. (This includes
2366 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2367
Dan Gohman5e7b8fb2010-05-03 14:55:22 +0000[diff] [blame]2368<li>An instruction <i>control-depends</i> on a
2369 <a href="#terminators">terminator instruction</a>
2370 if the terminator instruction has multiple successors and the instruction
2371 is always executed when control transfers to one of the successors, and
2372 may not be executed when control is transfered to another.</li>
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2373
2374<li>Dependence is transitive.</li>
2375
2376</ul>
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2377
2378<p>Whenever a trap value is generated, all values which depend on it evaluate
2379 to trap. If they have side effects, the evoke their side effects as if each
2380 operand with a trap value were undef. If they have externally-visible side
2381 effects, the behavior is undefined.</p>
2382
2383<p>Here are some examples:</p>
Dan Gohman54884272010-04-26 20:54:53 +0000[diff] [blame]2384
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2385<pre class="doc_code">
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2386entry:
2387 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2388 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2389 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2390 store i32 0, i32* %trap_yet_again ; undefined behavior
2391
2392 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2393 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2394
2395 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2396
2397 %narrowaddr = bitcast i32* @g to i16*
2398 %wideaddr = bitcast i32* @g to i64*
2399 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2400 %trap4 = load i64* %widaddr ; Returns a trap value.
2401
2402 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2403 %br i1 %cmp, %true, %end ; Branch to either destination.
2404
2405true:
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2406 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2407 ; it has undefined behavior.
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2408 br label %end
2409
2410end:
2411 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2412 ; Both edges into this PHI are
2413 ; control-dependent on %cmp, so this
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2414 ; always results in a trap value.
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2415
2416 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2417 ; so this is defined (ignoring earlier
2418 ; undefined behavior in this example).
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2419</pre>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2420
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2421</div>
2422
2423<!-- ======================================================================= -->
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2424<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2425 Blocks</a></div>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2426<div class="doc_text">
2427
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2428<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2429
2430<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner24f2e852009-10-27 21:49:40 +0000[diff] [blame]2431 basic block in the specified function, and always has an i8* type. Taking
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2432 the address of the entry block is illegal.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2433
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2434<p>This value only has defined behavior when used as an operand to the
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2435 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2436 against null. Pointer equality tests between labels addresses is undefined
2437 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2438 equal to the null pointer. This may also be passed around as an opaque
2439 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner0bae7b32009-10-27 21:44:20 +0000[diff] [blame]2440 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2441 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2442
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2443<p>Finally, some targets may provide defined semantics when
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2444 using the value as the operand to an inline assembly, but that is target
2445 specific.
2446 </p>
2447
2448</div>
2449
2450
2451<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2452<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2453</div>
2454
2455<div class="doc_text">
2456
2457<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2458 to be used as constants. Constant expressions may be of
2459 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2460 operation that does not have side effects (e.g. load and call are not
2461 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2462
2463<dl>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2464 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2465 <dd>Truncate a constant to another type. The bit size of CST must be larger
2466 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2467
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2468 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2469 <dd>Zero extend a constant to another type. The bit size of CST must be
Duncan Sandsced0daf2010-07-13 12:06:14 +0000[diff] [blame]2470 smaller than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2471
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2472 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2473 <dd>Sign extend a constant to another type. The bit size of CST must be
Duncan Sandsced0daf2010-07-13 12:06:14 +0000[diff] [blame]2474 smaller than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2475
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2476 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2477 <dd>Truncate a floating point constant to another floating point type. The
2478 size of CST must be larger than the size of TYPE. Both types must be
2479 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2480
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2481 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2482 <dd>Floating point extend a constant to another type. The size of CST must be
2483 smaller or equal to the size of TYPE. Both types must be floating
2484 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2485
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2486 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2487 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2488 constant. TYPE must be a scalar or vector integer type. CST must be of
2489 scalar or vector floating point type. Both CST and TYPE must be scalars,
2490 or vectors of the same number of elements. If the value won't fit in the
2491 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2492
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2493 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2494 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2495 constant. TYPE must be a scalar or vector integer type. CST must be of
2496 scalar or vector floating point type. Both CST and TYPE must be scalars,
2497 or vectors of the same number of elements. If the value won't fit in the
2498 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2499
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2500 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2501 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2502 constant. TYPE must be a scalar or vector floating point type. CST must be
2503 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2504 vectors of the same number of elements. If the value won't fit in the
2505 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2506
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2507 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2508 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2509 constant. TYPE must be a scalar or vector floating point type. CST must be
2510 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2511 vectors of the same number of elements. If the value won't fit in the
2512 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2513
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2514 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2515 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2516 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2517 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2518 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2519
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2520 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2521 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2522 type. CST must be of integer type. The CST value is zero extended,
2523 truncated, or unchanged to make it fit in a pointer size. This one is
2524 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2525
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2526 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2527 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2528 are the same as those for the <a href="#i_bitcast">bitcast
2529 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2530
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2531 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2532 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2533 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2534 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2535 instruction, the index list may have zero or more indexes, which are
2536 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2537
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2538 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2539 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2540
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2541 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2542 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2543
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2544 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2545 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2546
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2547 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2548 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2549 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2550
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2551 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2552 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2553 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2554
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2555 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2556 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2557 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2558
Nick Lewyckyeb94e312010-05-29 06:44:15 +0000[diff] [blame]2559 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2560 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2561 constants. The index list is interpreted in a similar manner as indices in
2562 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2563 index value must be specified.</dd>
2564
2565 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2566 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2567 constants. The index list is interpreted in a similar manner as indices in
2568 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2569 index value must be specified.</dd>
2570
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2571 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2572 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2573 be any of the <a href="#binaryops">binary</a>
2574 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2575 on operands are the same as those for the corresponding instruction
2576 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2577</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2578
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2579</div>
2580
2581<!-- *********************************************************************** -->
2582<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2583<!-- *********************************************************************** -->
2584
2585<!-- ======================================================================= -->
2586<div class="doc_subsection">
2587<a name="inlineasm">Inline Assembler Expressions</a>
2588</div>
2589
2590<div class="doc_text">
2591
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2592<p>LLVM supports inline assembler expressions (as opposed
2593 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2594 a special value. This value represents the inline assembler as a string
2595 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2596 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2597 expression has side effects, and a flag indicating whether the function
2598 containing the asm needs to align its stack conservatively. An example
2599 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2600
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2601<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2602i32 (i32) asm "bswap $0", "=r,r"
2603</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2604
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2605<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2606 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2607 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2608
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2609<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2610%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2611</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2612
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2613<p>Inline asms with side effects not visible in the constraint list must be
2614 marked as having side effects. This is done through the use of the
2615 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2616
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2617<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2618call void asm sideeffect "eieio", ""()
2619</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2620
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2621<p>In some cases inline asms will contain code that will not work unless the
2622 stack is aligned in some way, such as calls or SSE instructions on x86,
2623 yet will not contain code that does that alignment within the asm.
2624 The compiler should make conservative assumptions about what the asm might
2625 contain and should generate its usual stack alignment code in the prologue
2626 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2627
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2628<pre class="doc_code">
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2629call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2630</pre>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2631
2632<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2633 first.</p>
2634
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2635<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2636 documented here. Constraints on what can be done (e.g. duplication, moving,
2637 etc need to be documented). This is probably best done by reference to
2638 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnerbafc8372010-04-07 05:38:05 +0000[diff] [blame]2639</div>
2640
2641<div class="doc_subsubsection">
2642<a name="inlineasm_md">Inline Asm Metadata</a>
2643</div>
2644
2645<div class="doc_text">
2646
2647<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2648 attached to it that contains a constant integer. If present, the code
2649 generator will use the integer as the location cookie value when report
2650 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohmanfde3cd72010-04-28 00:36:01 +0000[diff] [blame]2651 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnerbafc8372010-04-07 05:38:05 +0000[diff] [blame]2652 source code that produced it. For example:</p>
2653
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2654<pre class="doc_code">
Chris Lattnerbafc8372010-04-07 05:38:05 +0000[diff] [blame]2655call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2656...
2657!42 = !{ i32 1234567 }
2658</pre>
Chris Lattnerbafc8372010-04-07 05:38:05 +0000[diff] [blame]2659
2660<p>It is up to the front-end to make sense of the magic numbers it places in the
2661 IR.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2662
2663</div>
2664
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2665<!-- ======================================================================= -->
2666<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2667 Strings</a>
2668</div>
2669
2670<div class="doc_text">
2671
2672<p>LLVM IR allows metadata to be attached to instructions in the program that
2673 can convey extra information about the code to the optimizers and code
2674 generator. One example application of metadata is source-level debug
2675 information. There are two metadata primitives: strings and nodes. All
2676 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2677 preceding exclamation point ('<tt>!</tt>').</p>
2678
2679<p>A metadata string is a string surrounded by double quotes. It can contain
2680 any character by escaping non-printable characters with "\xx" where "xx" is
2681 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2682
2683<p>Metadata nodes are represented with notation similar to structure constants
2684 (a comma separated list of elements, surrounded by braces and preceded by an
2685 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2686 10}</tt>". Metadata nodes can have any values as their operand.</p>
2687
2688<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2689 metadata nodes, which can be looked up in the module symbol table. For
2690 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2691
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2692<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2693 function is using two metadata arguments.</p>
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2694
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2695 <pre class="doc_code">
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2696 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2697 </pre>
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2698
2699<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2700 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2701
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2702 <pre class="doc_code">
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2703 %indvar.next = add i64 %indvar, 1, !dbg !21
2704 </pre>
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2705</div>
2706
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2707
2708<!-- *********************************************************************** -->
2709<div class="doc_section">
2710 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2711</div>
2712<!-- *********************************************************************** -->
2713
2714<p>LLVM has a number of "magic" global variables that contain data that affect
2715code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2716of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2717section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2718by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2719
2720<!-- ======================================================================= -->
2721<div class="doc_subsection">
2722<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2723</div>
2724
2725<div class="doc_text">
2726
2727<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2728href="#linkage_appending">appending linkage</a>. This array contains a list of
2729pointers to global variables and functions which may optionally have a pointer
2730cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2731
2732<pre>
2733 @X = global i8 4
2734 @Y = global i32 123
2735
2736 @llvm.used = appending global [2 x i8*] [
2737 i8* @X,
2738 i8* bitcast (i32* @Y to i8*)
2739 ], section "llvm.metadata"
2740</pre>
2741
2742<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2743compiler, assembler, and linker are required to treat the symbol as if there is
2744a reference to the global that it cannot see. For example, if a variable has
2745internal linkage and no references other than that from the <tt>@llvm.used</tt>
2746list, it cannot be deleted. This is commonly used to represent references from
2747inline asms and other things the compiler cannot "see", and corresponds to
2748"attribute((used))" in GNU C.</p>
2749
2750<p>On some targets, the code generator must emit a directive to the assembler or
2751object file to prevent the assembler and linker from molesting the symbol.</p>
2752
2753</div>
2754
2755<!-- ======================================================================= -->
2756<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2757<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2758</div>
2759
2760<div class="doc_text">
2761
2762<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2763<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2764touching the symbol. On targets that support it, this allows an intelligent
2765linker to optimize references to the symbol without being impeded as it would be
2766by <tt>@llvm.used</tt>.</p>
2767
2768<p>This is a rare construct that should only be used in rare circumstances, and
2769should not be exposed to source languages.</p>
2770
2771</div>
2772
2773<!-- ======================================================================= -->
2774<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2775<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2776</div>
2777
2778<div class="doc_text">
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2779<pre>
2780%0 = type { i32, void ()* }
David Chisnalla07a3c22010-04-30 19:27:35 +0000[diff] [blame]2781@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2782</pre>
2783<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor functions and associated priorities. The functions referenced by this array will be called in ascending order of priority (i.e. lowest first) when the module is loaded. The order of functions with the same priority is not defined.
2784</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2785
2786</div>
2787
2788<!-- ======================================================================= -->
2789<div class="doc_subsection">
2790<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2791</div>
2792
2793<div class="doc_text">
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2794<pre>
2795%0 = type { i32, void ()* }
David Chisnalla07a3c22010-04-30 19:27:35 +0000[diff] [blame]2796@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2797</pre>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2798
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2799<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions and associated priorities. The functions referenced by this array will be called in descending order of priority (i.e. highest first) when the module is loaded. The order of functions with the same priority is not defined.
2800</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2801
2802</div>
2803
2804
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2805<!-- *********************************************************************** -->
2806<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2807<!-- *********************************************************************** -->
2808
2809<div class="doc_text">
2810
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2811<p>The LLVM instruction set consists of several different classifications of
2812 instructions: <a href="#terminators">terminator
2813 instructions</a>, <a href="#binaryops">binary instructions</a>,
2814 <a href="#bitwiseops">bitwise binary instructions</a>,
2815 <a href="#memoryops">memory instructions</a>, and
2816 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2817
2818</div>
2819
2820<!-- ======================================================================= -->
2821<div class="doc_subsection"> <a name="terminators">Terminator
2822Instructions</a> </div>
2823
2824<div class="doc_text">
2825
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2826<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2827 in a program ends with a "Terminator" instruction, which indicates which
2828 block should be executed after the current block is finished. These
2829 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2830 control flow, not values (the one exception being the
2831 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2832
Duncan Sands048d8062010-04-15 20:35:54 +0000[diff] [blame]2833<p>There are seven different terminator instructions: the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2834 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2835 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2836 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendlingb4ae2292009-11-02 00:25:26 +0000[diff] [blame]2837 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2838 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2839 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2840 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2841
2842</div>
2843
2844<!-- _______________________________________________________________________ -->
2845<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2846Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2847
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2848<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2849
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2850<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2851<pre>
2852 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]2853 ret void <i>; Return from void function</i>
2854</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2855
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2856<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2857<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2858 a value) from a function back to the caller.</p>
2859
2860<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2861 value and then causes control flow, and one that just causes control flow to
2862 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2863
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2864<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2865<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2866 return value. The type of the return value must be a
2867 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2868
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2869<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2870 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2871 value or a return value with a type that does not match its type, or if it
2872 has a void return type and contains a '<tt>ret</tt>' instruction with a
2873 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2874
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2875<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2876<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2877 the calling function's context. If the caller is a
2878 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2879 instruction after the call. If the caller was an
2880 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2881 the beginning of the "normal" destination block. If the instruction returns
2882 a value, that value shall set the call or invoke instruction's return
2883 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2884
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2885<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2886<pre>
2887 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2888 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2889 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]2890</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2891
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2892</div>
2893<!-- _______________________________________________________________________ -->
2894<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2895
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2896<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2897
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2898<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2899<pre>
2900 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]2901</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2902
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2903<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2904<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2905 different basic block in the current function. There are two forms of this
2906 instruction, corresponding to a conditional branch and an unconditional
2907 branch.</p>
2908
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2909<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2910<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2911 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2912 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2913 target.</p>
2914
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2915<h5>Semantics:</h5>
2916<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2917 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2918 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2919 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2920
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2921<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2922<pre>
2923Test:
2924 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2925 br i1 %cond, label %IfEqual, label %IfUnequal
2926IfEqual:
2927 <a href="#i_ret">ret</a> i32 1
2928IfUnequal:
2929 <a href="#i_ret">ret</a> i32 0
2930</pre>
2931
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2932</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2933
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2934<!-- _______________________________________________________________________ -->
2935<div class="doc_subsubsection">
2936 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2937</div>
2938
2939<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2940
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2941<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2942<pre>
2943 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2944</pre>
2945
2946<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2947<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]2948 several different places. It is a generalization of the '<tt>br</tt>'
2949 instruction, allowing a branch to occur to one of many possible
2950 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2951
2952<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2953<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2954 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2955 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2956 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2957
2958<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2959<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2960 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2961 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2962 transferred to the corresponding destination; otherwise, control flow is
2963 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2964
2965<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2966<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2967 <tt>switch</tt> instruction, this instruction may be code generated in
2968 different ways. For example, it could be generated as a series of chained
2969 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2970
2971<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2972<pre>
2973 <i>; Emulate a conditional br instruction</i>
2974 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2975 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2976
2977 <i>; Emulate an unconditional br instruction</i>
2978 switch i32 0, label %dest [ ]
2979
2980 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2981 switch i32 %val, label %otherwise [ i32 0, label %onzero
2982 i32 1, label %onone
2983 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2984</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2985
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2986</div>
2987
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2988
2989<!-- _______________________________________________________________________ -->
2990<div class="doc_subsubsection">
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2991 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2992</div>
2993
2994<div class="doc_text">
2995
2996<h5>Syntax:</h5>
2997<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2998 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]2999</pre>
3000
3001<h5>Overview:</h5>
3002
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]3003<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3004 within the current function, whose address is specified by
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]3005 "<tt>address</tt>". Address must be derived from a <a
3006 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3007
3008<h5>Arguments:</h5>
3009
3010<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3011 rest of the arguments indicate the full set of possible destinations that the
3012 address may point to. Blocks are allowed to occur multiple times in the
3013 destination list, though this isn't particularly useful.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3014
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3015<p>This destination list is required so that dataflow analysis has an accurate
3016 understanding of the CFG.</p>
3017
3018<h5>Semantics:</h5>
3019
3020<p>Control transfers to the block specified in the address argument. All
3021 possible destination blocks must be listed in the label list, otherwise this
3022 instruction has undefined behavior. This implies that jumps to labels
3023 defined in other functions have undefined behavior as well.</p>
3024
3025<h5>Implementation:</h5>
3026
3027<p>This is typically implemented with a jump through a register.</p>
3028
3029<h5>Example:</h5>
3030<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]3031 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3032</pre>
3033
3034</div>
3035
3036
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3037<!-- _______________________________________________________________________ -->
3038<div class="doc_subsubsection">
3039 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3040</div>
3041
3042<div class="doc_text">
3043
3044<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3045<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]3046 &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]3047 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
3048</pre>
3049
3050<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3051<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3052 function, with the possibility of control flow transfer to either the
3053 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3054 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3055 control flow will return to the "normal" label. If the callee (or any
3056 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3057 instruction, control is interrupted and continued at the dynamically nearest
3058 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3059
3060<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3061<p>This instruction requires several arguments:</p>
3062
3063<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3064 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3065 convention</a> the call should use. If none is specified, the call
3066 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]3067
3068 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3069 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3070 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]3071
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3072 <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]3073 function value being invoked. In most cases, this is a direct function
3074 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3075 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3076
3077 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3078 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3079
3080 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]3081 signature argument types and parameter attributes. All arguments must be
3082 of <a href="#t_firstclass">first class</a> type. If the function
3083 signature indicates the function accepts a variable number of arguments,
3084 the extra arguments can be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3085
3086 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3087 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3088
3089 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3090 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3091
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]3092 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3093 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3094 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3095</ol>
3096
3097<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3098<p>This instruction is designed to operate as a standard
3099 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3100 primary difference is that it establishes an association with a label, which
3101 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3102
3103<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3104 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3105 exception. Additionally, this is important for implementation of
3106 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3107
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3108<p>For the purposes of the SSA form, the definition of the value returned by the
3109 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3110 block to the "normal" label. If the callee unwinds then no return value is
3111 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]3112
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]3113<p>Note that the code generator does not yet completely support unwind, and
3114that the invoke/unwind semantics are likely to change in future versions.</p>
3115
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3116<h5>Example:</h5>
3117<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]3118 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3119 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]3120 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3121 unwind label %TestCleanup <i>; {i32}:retval set</i>
3122</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3123
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3124</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3125
3126<!-- _______________________________________________________________________ -->
3127
3128<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3129Instruction</a> </div>
3130
3131<div class="doc_text">
3132
3133<h5>Syntax:</h5>
3134<pre>
3135 unwind
3136</pre>
3137
3138<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3139<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3140 at the first callee in the dynamic call stack which used
3141 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3142 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3143
3144<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3145<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3146 immediately halt. The dynamic call stack is then searched for the
3147 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3148 Once found, execution continues at the "exceptional" destination block
3149 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3150 instruction in the dynamic call chain, undefined behavior results.</p>
3151
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]3152<p>Note that the code generator does not yet completely support unwind, and
3153that the invoke/unwind semantics are likely to change in future versions.</p>
3154
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3155</div>
3156
3157<!-- _______________________________________________________________________ -->
3158
3159<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3160Instruction</a> </div>
3161
3162<div class="doc_text">
3163
3164<h5>Syntax:</h5>
3165<pre>
3166 unreachable
3167</pre>
3168
3169<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3170<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3171 instruction is used to inform the optimizer that a particular portion of the
3172 code is not reachable. This can be used to indicate that the code after a
3173 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3174
3175<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3176<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3177
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3178</div>
3179
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3180<!-- ======================================================================= -->
3181<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3182
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3183<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3184
3185<p>Binary operators are used to do most of the computation in a program. They
3186 require two operands of the same type, execute an operation on them, and
3187 produce a single value. The operands might represent multiple data, as is
3188 the case with the <a href="#t_vector">vector</a> data type. The result value
3189 has the same type as its operands.</p>
3190
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3191<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3192
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3193</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3194
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3195<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3196<div class="doc_subsubsection">
3197 <a name="i_add">'<tt>add</tt>' Instruction</a>
3198</div>
3199
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3200<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3201
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3202<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3203<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3204 &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]3205 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3206 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3207 &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]3208</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3209
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3210<h5>Overview:</h5>
3211<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3213<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3214<p>The two arguments to the '<tt>add</tt>' instruction must
3215 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3216 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3217
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3218<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3219<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3220
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3221<p>If the sum has unsigned overflow, the result returned is the mathematical
3222 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]3223
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3224<p>Because LLVM integers use a two's complement representation, this instruction
3225 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3226
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3227<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3228 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3229 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3230 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3231 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3232
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3233<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3234<pre>
3235 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3236</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3238</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3239
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3240<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3241<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3242 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3243</div>
3244
3245<div class="doc_text">
3246
3247<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3248<pre>
3249 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3250</pre>
3251
3252<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3253<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3254
3255<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3256<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3257 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3258 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3259
3260<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3261<p>The value produced is the floating point sum of the two operands.</p>
3262
3263<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3264<pre>
3265 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3266</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3267
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3268</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3269
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3270<!-- _______________________________________________________________________ -->
3271<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3272 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3273</div>
3274
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3275<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3276
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3277<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3278<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3279 &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]3280 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3281 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3282 &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]3283</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3284
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3285<h5>Overview:</h5>
3286<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3287 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3288
3289<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3290 '<tt>neg</tt>' instruction present in most other intermediate
3291 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3292
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3293<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3294<p>The two arguments to the '<tt>sub</tt>' instruction must
3295 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3296 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3298<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3299<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3300
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3301<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3302 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3303 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3304
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3305<p>Because LLVM integers use a two's complement representation, this instruction
3306 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3307
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3308<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3309 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3310 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3311 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3312 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3313
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3314<h5>Example:</h5>
3315<pre>
3316 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
3317 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
3318</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3319
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3320</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3321
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3322<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3323<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3324 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3325</div>
3326
3327<div class="doc_text">
3328
3329<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3330<pre>
3331 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3332</pre>
3333
3334<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3335<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3336 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3337
3338<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3339 '<tt>fneg</tt>' instruction present in most other intermediate
3340 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3341
3342<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]3343<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3344 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3345 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3346
3347<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3348<p>The value produced is the floating point difference of the two operands.</p>
3349
3350<h5>Example:</h5>
3351<pre>
3352 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3353 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3354</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3355
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3356</div>
3357
3358<!-- _______________________________________________________________________ -->
3359<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3360 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3361</div>
3362
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3363<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3364
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3365<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3366<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3367 &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]3368 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3369 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3370 &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]3371</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3372
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3373<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3374<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3375
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3376<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3377<p>The two arguments to the '<tt>mul</tt>' instruction must
3378 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3379 integer values. Both arguments must have identical types.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3380
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3381<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3382<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3383
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3384<p>If the result of the multiplication has unsigned overflow, the result
3385 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3386 width of the result.</p>
3387
3388<p>Because LLVM integers use a two's complement representation, and the result
3389 is the same width as the operands, this instruction returns the correct
3390 result for both signed and unsigned integers. If a full product
3391 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3392 be sign-extended or zero-extended as appropriate to the width of the full
3393 product.</p>
3394
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3395<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3396 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3397 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3398 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3399 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3400
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3401<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3402<pre>
3403 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3404</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3406</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3407
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3408<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3409<div class="doc_subsubsection">
3410 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3411</div>
3412
3413<div class="doc_text">
3414
3415<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3416<pre>
3417 &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]3418</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3419
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3420<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3421<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3422
3423<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3424<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3425 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3426 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3427
3428<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3429<p>The value produced is the floating point product of the two operands.</p>
3430
3431<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3432<pre>
3433 &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]3434</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3435
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3436</div>
3437
3438<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3439<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3440</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3441
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3442<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3443
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3444<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3445<pre>
3446 &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]3447</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3448
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3449<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3450<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3451
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3452<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3453<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3454 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3455 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3456
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3457<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3458<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3459
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3460<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3461 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3462
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3463<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3464
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3465<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3466<pre>
3467 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3468</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3469
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3470</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3471
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3472<!-- _______________________________________________________________________ -->
3473<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3474</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3475
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3476<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3477
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3478<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3479<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3480 &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]3481 &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]3482</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3483
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3484<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3485<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3486
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3487<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3488<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3489 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3490 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3491
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3492<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3493<p>The value produced is the signed integer quotient of the two operands rounded
3494 towards zero.</p>
3495
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3496<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3497 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3498
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3499<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3500 undefined behavior; this is a rare case, but can occur, for example, by doing
3501 a 32-bit division of -2147483648 by -1.</p>
3502
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3503<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanf7263862010-04-23 15:23:32 +0000[diff] [blame]3504 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
Dan Gohman29297b02010-07-11 00:08:34 +0000[diff] [blame]3505 be rounded.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3506
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3507<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3508<pre>
3509 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3510</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3511
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3512</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3513
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3514<!-- _______________________________________________________________________ -->
3515<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3516Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3517
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3518<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3519
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3520<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3521<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3522 &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]3523</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3524
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3525<h5>Overview:</h5>
3526<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3527
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3528<h5>Arguments:</h5>
3529<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3530 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3531 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3532
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3533<h5>Semantics:</h5>
3534<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3535
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3536<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3537<pre>
3538 &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]3539</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3540
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3541</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3542
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3543<!-- _______________________________________________________________________ -->
3544<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3545</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3546
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3547<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3548
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3549<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3550<pre>
3551 &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]3552</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3553
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3554<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3555<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3556 division of its two arguments.</p>
3557
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3558<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3559<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3560 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3561 values. Both arguments must have identical types.</p>
3562
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3563<h5>Semantics:</h5>
3564<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3565 This instruction always performs an unsigned division to get the
3566 remainder.</p>
3567
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3568<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3569 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3570
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3571<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3572
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3573<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3574<pre>
3575 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3576</pre>
3577
3578</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3579
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3580<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3581<div class="doc_subsubsection">
3582 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3583</div>
3584
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3585<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3586
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3587<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3588<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3589 &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]3590</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3591
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3592<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3593<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3594 division of its two operands. This instruction can also take
3595 <a href="#t_vector">vector</a> versions of the values in which case the
3596 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3597
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3598<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3599<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3600 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3601 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3602
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3603<h5>Semantics:</h5>
3604<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3605 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3606 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3607 a value. For more information about the difference,
3608 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3609 Math Forum</a>. For a table of how this is implemented in various languages,
3610 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3611 Wikipedia: modulo operation</a>.</p>
3612
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3613<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3614 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3615
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3616<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3617 Overflow also leads to undefined behavior; this is a rare case, but can
3618 occur, for example, by taking the remainder of a 32-bit division of
3619 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3620 lets srem be implemented using instructions that return both the result of
3621 the division and the remainder.)</p>
3622
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3623<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3624<pre>
3625 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3626</pre>
3627
3628</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3629
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3630<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3631<div class="doc_subsubsection">
3632 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3633
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3634<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3635
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3636<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3637<pre>
3638 &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]3639</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3640
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3641<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3642<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3643 its two operands.</p>
3644
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3645<h5>Arguments:</h5>
3646<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3647 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3648 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3650<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3651<p>This instruction returns the <i>remainder</i> of a division. The remainder
3652 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3653
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3654<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3655<pre>
3656 &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]3657</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3658
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3659</div>
3660
3661<!-- ======================================================================= -->
3662<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3663Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3664
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3665<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3666
3667<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3668 program. They are generally very efficient instructions and can commonly be
3669 strength reduced from other instructions. They require two operands of the
3670 same type, execute an operation on them, and produce a single value. The
3671 resulting value is the same type as its operands.</p>
3672
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3673</div>
3674
3675<!-- _______________________________________________________________________ -->
3676<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3677Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3678
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3679<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3680
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3681<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3682<pre>
3683 &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]3684</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3685
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3686<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3687<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3688 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3689
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3690<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3691<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3692 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3693 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3694
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3695<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3696<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3697 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3698 is (statically or dynamically) negative or equal to or larger than the number
3699 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3700 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3701 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3702
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3703<h5>Example:</h5>
3704<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3705 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3706 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3707 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3708 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3709 &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]3710</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3711
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3712</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3713
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3714<!-- _______________________________________________________________________ -->
3715<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3716Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3717
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3718<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3719
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3720<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3721<pre>
3722 &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]3723</pre>
3724
3725<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3726<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3727 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3728
3729<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3730<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3731 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3732 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3733
3734<h5>Semantics:</h5>
3735<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3736 significant bits of the result will be filled with zero bits after the shift.
3737 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3738 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3739 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3740 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3741
3742<h5>Example:</h5>
3743<pre>
3744 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3745 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3746 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3747 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3748 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3749 &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]3750</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3751
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3752</div>
3753
3754<!-- _______________________________________________________________________ -->
3755<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3756Instruction</a> </div>
3757<div class="doc_text">
3758
3759<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3760<pre>
3761 &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]3762</pre>
3763
3764<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3765<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3766 operand shifted to the right a specified number of bits with sign
3767 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3768
3769<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3770<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3771 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3772 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3773
3774<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3775<p>This instruction always performs an arithmetic shift right operation, The
3776 most significant bits of the result will be filled with the sign bit
3777 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3778 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3779 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3780 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3781
3782<h5>Example:</h5>
3783<pre>
3784 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3785 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3786 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3787 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3788 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3789 &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]3790</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3792</div>
3793
3794<!-- _______________________________________________________________________ -->
3795<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3796Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3797
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3798<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3799
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3800<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3801<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3802 &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]3803</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3804
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3805<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3806<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3807 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3808
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3809<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3810<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3811 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3812 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3813
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3814<h5>Semantics:</h5>
3815<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3816
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3817<table border="1" cellspacing="0" cellpadding="4">
3818 <tbody>
3819 <tr>
3820 <td>In0</td>
3821 <td>In1</td>
3822 <td>Out</td>
3823 </tr>
3824 <tr>
3825 <td>0</td>
3826 <td>0</td>
3827 <td>0</td>
3828 </tr>
3829 <tr>
3830 <td>0</td>
3831 <td>1</td>
3832 <td>0</td>
3833 </tr>
3834 <tr>
3835 <td>1</td>
3836 <td>0</td>
3837 <td>0</td>
3838 </tr>
3839 <tr>
3840 <td>1</td>
3841 <td>1</td>
3842 <td>1</td>
3843 </tr>
3844 </tbody>
3845</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3846
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3847<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3848<pre>
3849 &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]3850 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3851 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3852</pre>
3853</div>
3854<!-- _______________________________________________________________________ -->
3855<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3856
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3857<div class="doc_text">
3858
3859<h5>Syntax:</h5>
3860<pre>
3861 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3862</pre>
3863
3864<h5>Overview:</h5>
3865<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3866 two operands.</p>
3867
3868<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3869<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3870 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3871 values. Both arguments must have identical types.</p>
3872
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3873<h5>Semantics:</h5>
3874<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3875
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3876<table border="1" cellspacing="0" cellpadding="4">
3877 <tbody>
3878 <tr>
3879 <td>In0</td>
3880 <td>In1</td>
3881 <td>Out</td>
3882 </tr>
3883 <tr>
3884 <td>0</td>
3885 <td>0</td>
3886 <td>0</td>
3887 </tr>
3888 <tr>
3889 <td>0</td>
3890 <td>1</td>
3891 <td>1</td>
3892 </tr>
3893 <tr>
3894 <td>1</td>
3895 <td>0</td>
3896 <td>1</td>
3897 </tr>
3898 <tr>
3899 <td>1</td>
3900 <td>1</td>
3901 <td>1</td>
3902 </tr>
3903 </tbody>
3904</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3905
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3906<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3907<pre>
3908 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3909 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3910 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3911</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3912
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3913</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3914
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3915<!-- _______________________________________________________________________ -->
3916<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3917Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3918
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3919<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3920
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3921<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3922<pre>
3923 &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]3924</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3925
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3926<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3927<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3928 its two operands. The <tt>xor</tt> is used to implement the "one's
3929 complement" operation, which is the "~" operator in C.</p>
3930
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3931<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3932<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3933 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3934 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3935
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3936<h5>Semantics:</h5>
3937<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3938
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3939<table border="1" cellspacing="0" cellpadding="4">
3940 <tbody>
3941 <tr>
3942 <td>In0</td>
3943 <td>In1</td>
3944 <td>Out</td>
3945 </tr>
3946 <tr>
3947 <td>0</td>
3948 <td>0</td>
3949 <td>0</td>
3950 </tr>
3951 <tr>
3952 <td>0</td>
3953 <td>1</td>
3954 <td>1</td>
3955 </tr>
3956 <tr>
3957 <td>1</td>
3958 <td>0</td>
3959 <td>1</td>
3960 </tr>
3961 <tr>
3962 <td>1</td>
3963 <td>1</td>
3964 <td>0</td>
3965 </tr>
3966 </tbody>
3967</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3968
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3969<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3970<pre>
3971 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3972 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3973 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3974 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3975</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3976
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3977</div>
3978
3979<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3980<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3981 <a name="vectorops">Vector Operations</a>
3982</div>
3983
3984<div class="doc_text">
3985
3986<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3987 target-independent manner. These instructions cover the element-access and
3988 vector-specific operations needed to process vectors effectively. While LLVM
3989 does directly support these vector operations, many sophisticated algorithms
3990 will want to use target-specific intrinsics to take full advantage of a
3991 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3992
3993</div>
3994
3995<!-- _______________________________________________________________________ -->
3996<div class="doc_subsubsection">
3997 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3998</div>
3999
4000<div class="doc_text">
4001
4002<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4003<pre>
4004 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
4005</pre>
4006
4007<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4008<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4009 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4010
4011
4012<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4013<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4014 of <a href="#t_vector">vector</a> type. The second operand is an index
4015 indicating the position from which to extract the element. The index may be
4016 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4017
4018<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4019<p>The result is a scalar of the same type as the element type of
4020 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4021 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4022 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4023
4024<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4025<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4026 &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]4027</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4028
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4029</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4030
4031<!-- _______________________________________________________________________ -->
4032<div class="doc_subsubsection">
4033 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4034</div>
4035
4036<div class="doc_text">
4037
4038<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4039<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]4040 &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]4041</pre>
4042
4043<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4044<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4045 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4046
4047<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4048<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4049 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4050 whose type must equal the element type of the first operand. The third
4051 operand is an index indicating the position at which to insert the value.
4052 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4053
4054<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4055<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4056 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4057 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4058 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4059
4060<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4061<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4062 &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]4063</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4064
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4065</div>
4066
4067<!-- _______________________________________________________________________ -->
4068<div class="doc_subsubsection">
4069 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4070</div>
4071
4072<div class="doc_text">
4073
4074<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4075<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]4076 &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]4077</pre>
4078
4079<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4080<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4081 from two input vectors, returning a vector with the same element type as the
4082 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4083
4084<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4085<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4086 with types that match each other. The third argument is a shuffle mask whose
4087 element type is always 'i32'. The result of the instruction is a vector
4088 whose length is the same as the shuffle mask and whose element type is the
4089 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4090
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4091<p>The shuffle mask operand is required to be a constant vector with either
4092 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4093
4094<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4095<p>The elements of the two input vectors are numbered from left to right across
4096 both of the vectors. The shuffle mask operand specifies, for each element of
4097 the result vector, which element of the two input vectors the result element
4098 gets. The element selector may be undef (meaning "don't care") and the
4099 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4100
4101<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4102<pre>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4103 &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]4104 &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]4105 &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]4106 &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]4107 &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]4108 &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]4109 &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]4110 &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]4111</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4112
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4113</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4114
4115<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4116<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4117 <a name="aggregateops">Aggregate Operations</a>
4118</div>
4119
4120<div class="doc_text">
4121
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4122<p>LLVM supports several instructions for working with
4123 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4124
4125</div>
4126
4127<!-- _______________________________________________________________________ -->
4128<div class="doc_subsubsection">
4129 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4130</div>
4131
4132<div class="doc_text">
4133
4134<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4135<pre>
4136 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4137</pre>
4138
4139<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4140<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4141 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4142
4143<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4144<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4145 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4146 <a href="#t_array">array</a> type. The operands are constant indices to
4147 specify which value to extract in a similar manner as indices in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4148 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4149
4150<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4151<p>The result is the value at the position in the aggregate specified by the
4152 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4153
4154<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4155<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4156 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4157</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4158
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4159</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4160
4161<!-- _______________________________________________________________________ -->
4162<div class="doc_subsubsection">
4163 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4164</div>
4165
4166<div class="doc_text">
4167
4168<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4169<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]4170 &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]4171</pre>
4172
4173<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4174<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4175 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4176
4177<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4178<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4179 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4180 <a href="#t_array">array</a> type. The second operand is a first-class
4181 value to insert. The following operands are constant indices indicating
4182 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]4183 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4184 value to insert must have the same type as the value identified by the
4185 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4186
4187<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4188<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4189 that of <tt>val</tt> except that the value at the position specified by the
4190 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4191
4192<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4193<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]4194 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4195 %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]4196</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4197
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4198</div>
4199
4200
4201<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4202<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4203 <a name="memoryops">Memory Access and Addressing Operations</a>
4204</div>
4205
4206<div class="doc_text">
4207
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4208<p>A key design point of an SSA-based representation is how it represents
4209 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]4210 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4211 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4212
4213</div>
4214
4215<!-- _______________________________________________________________________ -->
4216<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4217 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4218</div>
4219
4220<div class="doc_text">
4221
4222<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4223<pre>
Dan Gohman3eb67d52010-05-28 01:14:11 +0000[diff] [blame]4224 &lt;result&gt; = alloca &lt;type&gt;[, &lt;ty&gt; &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4225</pre>
4226
4227<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4228<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4229 currently executing function, to be automatically released when this function
4230 returns to its caller. The object is always allocated in the generic address
4231 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4232
4233<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4234<p>The '<tt>alloca</tt>' instruction
4235 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4236 runtime stack, returning a pointer of the appropriate type to the program.
4237 If "NumElements" is specified, it is the number of elements allocated,
4238 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4239 specified, the value result of the allocation is guaranteed to be aligned to
4240 at least that boundary. If not specified, or if zero, the target can choose
4241 to align the allocation on any convenient boundary compatible with the
4242 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4243
4244<p>'<tt>type</tt>' may be any sized type.</p>
4245
4246<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]4247<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4248 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4249 memory is automatically released when the function returns. The
4250 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4251 variables that must have an address available. When the function returns
4252 (either with the <tt><a href="#i_ret">ret</a></tt>
4253 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4254 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4255
4256<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4257<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]4258 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4259 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4260 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4261 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4262</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4263
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4264</div>
4265
4266<!-- _______________________________________________________________________ -->
4267<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4268Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4269
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4270<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4271
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4272<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4273<pre>
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4274 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4275 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4276 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4277</pre>
4278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4279<h5>Overview:</h5>
4280<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4281
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4282<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4283<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4284 from which to load. The pointer must point to
4285 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4286 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]4287 number or order of execution of this <tt>load</tt> with other <a
4288 href="#volatile">volatile operations</a>.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4289
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4290<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4291 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]4292 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4293 alignment for the target. It is the responsibility of the code emitter to
4294 ensure that the alignment information is correct. Overestimating the
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4295 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4296 produce less efficient code. An alignment of 1 is always safe.</p>
4297
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4298<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4299 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4300 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4301 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4302 and code generator that this load is not expected to be reused in the cache.
4303 The code generator may select special instructions to save cache bandwidth,
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4304 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4305
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4306<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4307<p>The location of memory pointed to is loaded. If the value being loaded is of
4308 scalar type then the number of bytes read does not exceed the minimum number
4309 of bytes needed to hold all bits of the type. For example, loading an
4310 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4311 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4312 is undefined if the value was not originally written using a store of the
4313 same type.</p>
4314
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4315<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4316<pre>
4317 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4318 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4319 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
4320</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4321
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4322</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4323
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4324<!-- _______________________________________________________________________ -->
4325<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4326Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4327
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4328<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4329
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4330<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4331<pre>
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]4332 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
4333 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4334</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4335
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4336<h5>Overview:</h5>
4337<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4338
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4339<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4340<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4341 and an address at which to store it. The type of the
4342 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4343 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]4344 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4345 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4346 order of execution of this <tt>store</tt> with other <a
4347 href="#volatile">volatile operations</a>.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4348
4349<p>The optional constant "align" argument specifies the alignment of the
4350 operation (that is, the alignment of the memory address). A value of 0 or an
4351 omitted "align" argument means that the operation has the preferential
4352 alignment for the target. It is the responsibility of the code emitter to
4353 ensure that the alignment information is correct. Overestimating the
4354 alignment results in an undefined behavior. Underestimating the alignment may
4355 produce less efficient code. An alignment of 1 is always safe.</p>
4356
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4357<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]4358 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4359 value 1. The existence of the !nontemporal metatadata on the
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4360 instruction tells the optimizer and code generator that this load is
4361 not expected to be reused in the cache. The code generator may
4362 select special instructions to save cache bandwidth, such as the
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4363 MOVNT instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4364
4365
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4366<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4367<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4368 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4369 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4370 does not exceed the minimum number of bytes needed to hold all bits of the
4371 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4372 writing a value of a type like <tt>i20</tt> with a size that is not an
4373 integral number of bytes, it is unspecified what happens to the extra bits
4374 that do not belong to the type, but they will typically be overwritten.</p>
4375
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4376<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4377<pre>
4378 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4379 store i32 3, i32* %ptr <i>; yields {void}</i>
4380 %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]4381</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4382
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4383</div>
4384
4385<!-- _______________________________________________________________________ -->
4386<div class="doc_subsubsection">
4387 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4388</div>
4389
4390<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4391
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4392<h5>Syntax:</h5>
4393<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4394 &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]4395 &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]4396</pre>
4397
4398<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4399<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4400 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4401 It performs address calculation only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4402
4403<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4404<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4405 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4406 elements of the aggregate object are indexed. The interpretation of each
4407 index is dependent on the type being indexed into. The first index always
4408 indexes the pointer value given as the first argument, the second index
4409 indexes a value of the type pointed to (not necessarily the value directly
4410 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4411 indexed into must be a pointer value, subsequent types can be arrays,
4412 vectors, structs and unions. Note that subsequent types being indexed into
4413 can never be pointers, since that would require loading the pointer before
4414 continuing calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4415
4416<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]4417 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4418 integer <b>constants</b> are allowed. When indexing into an array, pointer
4419 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]4420 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4421
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4422<p>For example, let's consider a C code fragment and how it gets compiled to
4423 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4424
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]4425<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4426struct RT {
4427 char A;
4428 int B[10][20];
4429 char C;
4430};
4431struct ST {
4432 int X;
4433 double Y;
4434 struct RT Z;
4435};
4436
4437int *foo(struct ST *s) {
4438 return &amp;s[1].Z.B[5][13];
4439}
4440</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4441
4442<p>The LLVM code generated by the GCC frontend is:</p>
4443
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]4444<pre class="doc_code">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4445%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4446%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4447
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4448define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4449entry:
4450 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4451 ret i32* %reg
4452}
4453</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4454
4455<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4456<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]4457 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4458 }</tt>' type, a structure. The second index indexes into the third element
4459 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4460 i8 }</tt>' type, another structure. The third index indexes into the second
4461 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4462 array. The two dimensions of the array are subscripted into, yielding an
4463 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4464 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4465
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4466<p>Note that it is perfectly legal to index partially through a structure,
4467 returning a pointer to an inner element. Because of this, the LLVM code for
4468 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4469
4470<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4471 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4472 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4473 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4474 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4475 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4476 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4477 ret i32* %t5
4478 }
4479</pre>
4480
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4481<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohmanf7263862010-04-23 15:23:32 +0000[diff] [blame]4482 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4483 base pointer is not an <i>in bounds</i> address of an allocated object,
4484 or if any of the addresses that would be formed by successive addition of
4485 the offsets implied by the indices to the base address with infinitely
4486 precise arithmetic are not an <i>in bounds</i> address of that allocated
4487 object. The <i>in bounds</i> addresses for an allocated object are all
4488 the addresses that point into the object, plus the address one byte past
4489 the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4490
4491<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4492 the base address with silently-wrapping two's complement arithmetic, and
4493 the result value of the <tt>getelementptr</tt> may be outside the object
4494 pointed to by the base pointer. The result value may not necessarily be
4495 used to access memory though, even if it happens to point into allocated
4496 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4497 section for more information.</p>
4498
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4499<p>The getelementptr instruction is often confusing. For some more insight into
4500 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4501
4502<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4503<pre>
4504 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4505 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4506 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4507 %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]4508 <i>; yields i8*:eptr</i>
4509 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4510 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4511 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4512</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4513
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4514</div>
4515
4516<!-- ======================================================================= -->
4517<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4518</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4519
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4520<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4521
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4522<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4523 which all take a single operand and a type. They perform various bit
4524 conversions on the operand.</p>
4525
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4526</div>
4527
4528<!-- _______________________________________________________________________ -->
4529<div class="doc_subsubsection">
4530 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4531</div>
4532<div class="doc_text">
4533
4534<h5>Syntax:</h5>
4535<pre>
4536 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4537</pre>
4538
4539<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4540<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4541 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4542
4543<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4544<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4545 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4546 size and type of the result, which must be
4547 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4548 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4549 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4550
4551<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4552<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4553 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4554 source size must be larger than the destination size, <tt>trunc</tt> cannot
4555 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4556
4557<h5>Example:</h5>
4558<pre>
4559 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4560 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4561 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4562</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4563
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4564</div>
4565
4566<!-- _______________________________________________________________________ -->
4567<div class="doc_subsubsection">
4568 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4569</div>
4570<div class="doc_text">
4571
4572<h5>Syntax:</h5>
4573<pre>
4574 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4575</pre>
4576
4577<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4578<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4579 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4580
4581
4582<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4583<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]4584 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4585 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]4586 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4587 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4588
4589<h5>Semantics:</h5>
4590<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]4591 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4592
4593<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4594
4595<h5>Example:</h5>
4596<pre>
4597 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4598 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4599</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4601</div>
4602
4603<!-- _______________________________________________________________________ -->
4604<div class="doc_subsubsection">
4605 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4606</div>
4607<div class="doc_text">
4608
4609<h5>Syntax:</h5>
4610<pre>
4611 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4612</pre>
4613
4614<h5>Overview:</h5>
4615<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4616
4617<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4618<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]4619 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4620 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]4621 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4622 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4623
4624<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4625<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4626 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4627 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4628
4629<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4630
4631<h5>Example:</h5>
4632<pre>
4633 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4634 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4635</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4636
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4637</div>
4638
4639<!-- _______________________________________________________________________ -->
4640<div class="doc_subsubsection">
4641 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4642</div>
4643
4644<div class="doc_text">
4645
4646<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4647<pre>
4648 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4649</pre>
4650
4651<h5>Overview:</h5>
4652<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4653 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4654
4655<h5>Arguments:</h5>
4656<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4657 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4658 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]4659 <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]4660 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4661
4662<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4663<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4664 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4665 <a href="#t_floating">floating point</a> type. If the value cannot fit
4666 within the destination type, <tt>ty2</tt>, then the results are
4667 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4668
4669<h5>Example:</h5>
4670<pre>
4671 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4672 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4673</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4674
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4675</div>
4676
4677<!-- _______________________________________________________________________ -->
4678<div class="doc_subsubsection">
4679 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4680</div>
4681<div class="doc_text">
4682
4683<h5>Syntax:</h5>
4684<pre>
4685 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4686</pre>
4687
4688<h5>Overview:</h5>
4689<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]4690 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4691
4692<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4693<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4694 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4695 a <a href="#t_floating">floating point</a> type to cast it to. The source
4696 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4697
4698<h5>Semantics:</h5>
4699<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4700 <a href="#t_floating">floating point</a> type to a larger
4701 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4702 used to make a <i>no-op cast</i> because it always changes bits. Use
4703 <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]4704
4705<h5>Example:</h5>
4706<pre>
4707 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4708 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4709</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4710
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4711</div>
4712
4713<!-- _______________________________________________________________________ -->
4714<div class="doc_subsubsection">
4715 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4716</div>
4717<div class="doc_text">
4718
4719<h5>Syntax:</h5>
4720<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4721 &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]4722</pre>
4723
4724<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4725<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4726 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4727
4728<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4729<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4730 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4731 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4732 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4733 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4734
4735<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4736<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4737 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4738 towards zero) unsigned integer value. If the value cannot fit
4739 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4740
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4741<h5>Example:</h5>
4742<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4743 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4744 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4745 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4746</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4747
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4748</div>
4749
4750<!-- _______________________________________________________________________ -->
4751<div class="doc_subsubsection">
4752 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4753</div>
4754<div class="doc_text">
4755
4756<h5>Syntax:</h5>
4757<pre>
4758 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4759</pre>
4760
4761<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4762<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4763 <a href="#t_floating">floating point</a> <tt>value</tt> to
4764 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4765
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4766<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4767<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4768 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4769 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4770 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4771 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4772
4773<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4774<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4775 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4776 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4777 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4778
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4779<h5>Example:</h5>
4780<pre>
4781 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4782 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4783 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4784</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4785
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4786</div>
4787
4788<!-- _______________________________________________________________________ -->
4789<div class="doc_subsubsection">
4790 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4791</div>
4792<div class="doc_text">
4793
4794<h5>Syntax:</h5>
4795<pre>
4796 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4797</pre>
4798
4799<h5>Overview:</h5>
4800<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4801 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4803<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4804<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]4805 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4806 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4807 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4808 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4809
4810<h5>Semantics:</h5>
4811<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4812 integer quantity and converts it to the corresponding floating point
4813 value. If the value cannot fit in the floating point value, the results are
4814 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4815
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4816<h5>Example:</h5>
4817<pre>
4818 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4819 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4820</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4821
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4822</div>
4823
4824<!-- _______________________________________________________________________ -->
4825<div class="doc_subsubsection">
4826 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4827</div>
4828<div class="doc_text">
4829
4830<h5>Syntax:</h5>
4831<pre>
4832 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4833</pre>
4834
4835<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4836<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4837 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4838
4839<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4840<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]4841 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4842 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4843 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4844 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4845
4846<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4847<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4848 quantity and converts it to the corresponding floating point value. If the
4849 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4850
4851<h5>Example:</h5>
4852<pre>
4853 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4854 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4855</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4856
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4857</div>
4858
4859<!-- _______________________________________________________________________ -->
4860<div class="doc_subsubsection">
4861 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4862</div>
4863<div class="doc_text">
4864
4865<h5>Syntax:</h5>
4866<pre>
4867 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4868</pre>
4869
4870<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4871<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4872 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4873
4874<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4875<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4876 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4877 <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]4878
4879<h5>Semantics:</h5>
4880<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4881 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4882 truncating or zero extending that value to the size of the integer type. If
4883 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4884 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4885 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4886 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4887
4888<h5>Example:</h5>
4889<pre>
4890 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4891 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4892</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4893
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4894</div>
4895
4896<!-- _______________________________________________________________________ -->
4897<div class="doc_subsubsection">
4898 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4899</div>
4900<div class="doc_text">
4901
4902<h5>Syntax:</h5>
4903<pre>
4904 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4905</pre>
4906
4907<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4908<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4909 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4910
4911<h5>Arguments:</h5>
4912<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4913 value to cast, and a type to cast it to, which must be a
4914 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4915
4916<h5>Semantics:</h5>
4917<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4918 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4919 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4920 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4921 than the size of a pointer then a zero extension is done. If they are the
4922 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4923
4924<h5>Example:</h5>
4925<pre>
4926 %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]4927 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4928 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4929</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4930
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4931</div>
4932
4933<!-- _______________________________________________________________________ -->
4934<div class="doc_subsubsection">
4935 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4936</div>
4937<div class="doc_text">
4938
4939<h5>Syntax:</h5>
4940<pre>
4941 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4942</pre>
4943
4944<h5>Overview:</h5>
4945<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4946 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4947
4948<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4949<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4950 non-aggregate first class value, and a type to cast it to, which must also be
4951 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4952 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4953 identical. If the source type is a pointer, the destination type must also be
4954 a pointer. This instruction supports bitwise conversion of vectors to
4955 integers and to vectors of other types (as long as they have the same
4956 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4957
4958<h5>Semantics:</h5>
4959<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4960 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4961 this conversion. The conversion is done as if the <tt>value</tt> had been
4962 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4963 be converted to other pointer types with this instruction. To convert
4964 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4965 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4966
4967<h5>Example:</h5>
4968<pre>
4969 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4970 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4971 %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]4972</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4973
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4974</div>
4975
4976<!-- ======================================================================= -->
4977<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4978
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4979<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4980
4981<p>The instructions in this category are the "miscellaneous" instructions, which
4982 defy better classification.</p>
4983
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4984</div>
4985
4986<!-- _______________________________________________________________________ -->
4987<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4988</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4989
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4990<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4991
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4992<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4993<pre>
4994 &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]4995</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4996
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4997<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4998<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4999 boolean values based on comparison of its two integer, integer vector, or
5000 pointer operands.</p>
5001
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5002<h5>Arguments:</h5>
5003<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5004 the condition code indicating the kind of comparison to perform. It is not a
5005 value, just a keyword. The possible condition code are:</p>
5006
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5007<ol>
5008 <li><tt>eq</tt>: equal</li>
5009 <li><tt>ne</tt>: not equal </li>
5010 <li><tt>ugt</tt>: unsigned greater than</li>
5011 <li><tt>uge</tt>: unsigned greater or equal</li>
5012 <li><tt>ult</tt>: unsigned less than</li>
5013 <li><tt>ule</tt>: unsigned less or equal</li>
5014 <li><tt>sgt</tt>: signed greater than</li>
5015 <li><tt>sge</tt>: signed greater or equal</li>
5016 <li><tt>slt</tt>: signed less than</li>
5017 <li><tt>sle</tt>: signed less or equal</li>
5018</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5019
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5020<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5021 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5022 typed. They must also be identical types.</p>
5023
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5024<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5025<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5026 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]5027 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]5028 result, as follows:</p>
5029
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5030<ol>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5031 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5032 <tt>false</tt> otherwise. No sign interpretation is necessary or
5033 performed.</li>
5034
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5035 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5036 <tt>false</tt> otherwise. No sign interpretation is necessary or
5037 performed.</li>
5038
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5039 <li><tt>ugt</tt>: interprets the operands as unsigned 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>uge</tt>: interprets the operands as unsigned 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>ult</tt>: interprets the operands as unsigned 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>ule</tt>: interprets the operands as unsigned 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>
5051
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5052 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5053 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5054
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5055 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5056 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5057 to <tt>op2</tt>.</li>
5058
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5059 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5060 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5061
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5062 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5063 <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]5064</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5065
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5066<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5067 values are compared as if they were integers.</p>
5068
5069<p>If the operands are integer vectors, then they are compared element by
5070 element. The result is an <tt>i1</tt> vector with the same number of elements
5071 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5072
5073<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5074<pre>
5075 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5076 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5077 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5078 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5079 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5080 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
5081</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5082
5083<p>Note that the code generator does not yet support vector types with
5084 the <tt>icmp</tt> instruction.</p>
5085
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5086</div>
5087
5088<!-- _______________________________________________________________________ -->
5089<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5090</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5091
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5092<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5093
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5094<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5095<pre>
5096 &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]5097</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5098
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5099<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5100<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5101 values based on comparison of its operands.</p>
5102
5103<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]5104(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5105
5106<p>If the operands are floating point vectors, then the result type is a vector
5107 of boolean with the same number of elements as the operands being
5108 compared.</p>
5109
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5110<h5>Arguments:</h5>
5111<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5112 the condition code indicating the kind of comparison to perform. It is not a
5113 value, just a keyword. The possible condition code are:</p>
5114
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5115<ol>
5116 <li><tt>false</tt>: no comparison, always returns false</li>
5117 <li><tt>oeq</tt>: ordered and equal</li>
5118 <li><tt>ogt</tt>: ordered and greater than </li>
5119 <li><tt>oge</tt>: ordered and greater than or equal</li>
5120 <li><tt>olt</tt>: ordered and less than </li>
5121 <li><tt>ole</tt>: ordered and less than or equal</li>
5122 <li><tt>one</tt>: ordered and not equal</li>
5123 <li><tt>ord</tt>: ordered (no nans)</li>
5124 <li><tt>ueq</tt>: unordered or equal</li>
5125 <li><tt>ugt</tt>: unordered or greater than </li>
5126 <li><tt>uge</tt>: unordered or greater than or equal</li>
5127 <li><tt>ult</tt>: unordered or less than </li>
5128 <li><tt>ule</tt>: unordered or less than or equal</li>
5129 <li><tt>une</tt>: unordered or not equal</li>
5130 <li><tt>uno</tt>: unordered (either nans)</li>
5131 <li><tt>true</tt>: no comparison, always returns true</li>
5132</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5133
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5134<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5135 <i>unordered</i> means that either operand may be a QNAN.</p>
5136
5137<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5138 a <a href="#t_floating">floating point</a> type or
5139 a <a href="#t_vector">vector</a> of floating point type. They must have
5140 identical types.</p>
5141
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5142<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]5143<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5144 according to the condition code given as <tt>cond</tt>. If the operands are
5145 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]5146 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5147 follows:</p>
5148
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5149<ol>
5150 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5151
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5152 <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]5153 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5154
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5155 <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]5156 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5157
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5158 <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]5159 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5160
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5161 <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]5162 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5163
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5164 <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]5165 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5166
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5167 <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]5168 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5169
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5170 <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]5171
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5172 <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]5173 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5174
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5175 <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]5176 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5177
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5178 <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]5179 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5180
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5181 <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]5182 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5183
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5184 <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]5185 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5186
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5187 <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]5188 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5189
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5190 <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]5191
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5192 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5193</ol>
5194
5195<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5196<pre>
5197 &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]5198 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5199 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5200 &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]5201</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5202
5203<p>Note that the code generator does not yet support vector types with
5204 the <tt>fcmp</tt> instruction.</p>
5205
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5206</div>
5207
5208<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]5209<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5210 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5211</div>
5212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5213<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5214
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5215<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5216<pre>
5217 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5218</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5219
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5220<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5221<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5222 SSA graph representing the function.</p>
5223
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5224<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5225<p>The type of the incoming values is specified with the first type field. After
5226 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5227 one pair for each predecessor basic block of the current block. Only values
5228 of <a href="#t_firstclass">first class</a> type may be used as the value
5229 arguments to the PHI node. Only labels may be used as the label
5230 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5231
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5232<p>There must be no non-phi instructions between the start of a basic block and
5233 the PHI instructions: i.e. PHI instructions must be first in a basic
5234 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5235
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5236<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5237 occur on the edge from the corresponding predecessor block to the current
5238 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5239 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]5240
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5241<h5>Semantics:</h5>
5242<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5243 specified by the pair corresponding to the predecessor basic block that
5244 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5245
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5246<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5247<pre>
5248Loop: ; Infinite loop that counts from 0 on up...
5249 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5250 %nextindvar = add i32 %indvar, 1
5251 br label %Loop
5252</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5253
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5254</div>
5255
5256<!-- _______________________________________________________________________ -->
5257<div class="doc_subsubsection">
5258 <a name="i_select">'<tt>select</tt>' Instruction</a>
5259</div>
5260
5261<div class="doc_text">
5262
5263<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5264<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]5265 &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>
5266
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5267 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5268</pre>
5269
5270<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5271<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5272 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5273
5274
5275<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5276<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5277 values indicating the condition, and two values of the
5278 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5279 vectors and the condition is a scalar, then entire vectors are selected, not
5280 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5281
5282<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5283<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5284 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5285
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5286<p>If the condition is a vector of i1, then the value arguments must be vectors
5287 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5288
5289<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5290<pre>
5291 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
5292</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5293
5294<p>Note that the code generator does not yet support conditions
5295 with vector type.</p>
5296
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5297</div>
5298
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5299<!-- _______________________________________________________________________ -->
5300<div class="doc_subsubsection">
5301 <a name="i_call">'<tt>call</tt>' Instruction</a>
5302</div>
5303
5304<div class="doc_text">
5305
5306<h5>Syntax:</h5>
5307<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]5308 &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]5309</pre>
5310
5311<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5312<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
5313
5314<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5315<p>This instruction requires several arguments:</p>
5316
5317<ol>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5318 <li>The optional "tail" marker indicates that the callee function does not
5319 access any allocas or varargs in the caller. Note that calls may be
5320 marked "tail" even if they do not occur before
5321 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5322 present, the function call is eligible for tail call optimization,
5323 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengcc7495c2010-03-08 21:05:02 +0000[diff] [blame]5324 optimized into a jump</a>. The code generator may optimize calls marked
5325 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5326 sibling call optimization</a> when the caller and callee have
5327 matching signatures, or 2) forced tail call optimization when the
5328 following extra requirements are met:
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5329 <ul>
5330 <li>Caller and callee both have the calling
5331 convention <tt>fastcc</tt>.</li>
5332 <li>The call is in tail position (ret immediately follows call and ret
5333 uses value of call or is void).</li>
5334 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman1be84f02010-03-02 01:08:11 +0000[diff] [blame]5335 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5336 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5337 constraints are met.</a></li>
5338 </ul>
5339 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5340
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5341 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5342 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5343 defaults to using C calling conventions. The calling convention of the
5344 call must match the calling convention of the target function, or else the
5345 behavior is undefined.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5346
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5347 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5348 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5349 '<tt>inreg</tt>' attributes are valid here.</li>
5350
5351 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5352 type of the return value. Functions that return no value are marked
5353 <tt><a href="#t_void">void</a></tt>.</li>
5354
5355 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5356 being invoked. The argument types must match the types implied by this
5357 signature. This type can be omitted if the function is not varargs and if
5358 the function type does not return a pointer to a function.</li>
5359
5360 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5361 be invoked. In most cases, this is a direct function invocation, but
5362 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5363 to function value.</li>
5364
5365 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]5366 signature argument types and parameter attributes. All arguments must be
5367 of <a href="#t_firstclass">first class</a> type. If the function
5368 signature indicates the function accepts a variable number of arguments,
5369 the extra arguments can be specified.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5370
5371 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5372 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5373 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5374</ol>
5375
5376<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5377<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5378 a specified function, with its incoming arguments bound to the specified
5379 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5380 function, control flow continues with the instruction after the function
5381 call, and the return value of the function is bound to the result
5382 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5383
5384<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5385<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5386 %retval = call i32 @test(i32 %argc)
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]5387 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5388 %X = tail call i32 @foo() <i>; yields i32</i>
5389 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5390 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5391
5392 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5393 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5394 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5395 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5396 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5397 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5398</pre>
5399
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5400<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5401standard C99 library as being the C99 library functions, and may perform
5402optimizations or generate code for them under that assumption. This is
5403something we'd like to change in the future to provide better support for
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5404freestanding environments and non-C-based languages.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5406</div>
5407
5408<!-- _______________________________________________________________________ -->
5409<div class="doc_subsubsection">
5410 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5411</div>
5412
5413<div class="doc_text">
5414
5415<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5416<pre>
5417 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5418</pre>
5419
5420<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5421<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5422 the "variable argument" area of a function call. It is used to implement the
5423 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5424
5425<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5426<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5427 argument. It returns a value of the specified argument type and increments
5428 the <tt>va_list</tt> to point to the next argument. The actual type
5429 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5430
5431<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5432<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5433 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5434 to the next argument. For more information, see the variable argument
5435 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5436
5437<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]5438 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5439 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5440
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5441<p><tt>va_arg</tt> is an LLVM instruction instead of
5442 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5443 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5444
5445<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5446<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5447
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5448<p>Note that the code generator does not yet fully support va_arg on many
5449 targets. Also, it does not currently support va_arg with aggregate types on
5450 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5451
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5452</div>
5453
5454<!-- *********************************************************************** -->
5455<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5456<!-- *********************************************************************** -->
5457
5458<div class="doc_text">
5459
5460<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5461 well known names and semantics and are required to follow certain
5462 restrictions. Overall, these intrinsics represent an extension mechanism for
5463 the LLVM language that does not require changing all of the transformations
5464 in LLVM when adding to the language (or the bitcode reader/writer, the
5465 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5466
5467<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5468 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5469 begin with this prefix. Intrinsic functions must always be external
5470 functions: you cannot define the body of intrinsic functions. Intrinsic
5471 functions may only be used in call or invoke instructions: it is illegal to
5472 take the address of an intrinsic function. Additionally, because intrinsic
5473 functions are part of the LLVM language, it is required if any are added that
5474 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5475
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5476<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5477 family of functions that perform the same operation but on different data
5478 types. Because LLVM can represent over 8 million different integer types,
5479 overloading is used commonly to allow an intrinsic function to operate on any
5480 integer type. One or more of the argument types or the result type can be
5481 overloaded to accept any integer type. Argument types may also be defined as
5482 exactly matching a previous argument's type or the result type. This allows
5483 an intrinsic function which accepts multiple arguments, but needs all of them
5484 to be of the same type, to only be overloaded with respect to a single
5485 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5486
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5487<p>Overloaded intrinsics will have the names of its overloaded argument types
5488 encoded into its function name, each preceded by a period. Only those types
5489 which are overloaded result in a name suffix. Arguments whose type is matched
5490 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5491 can take an integer of any width and returns an integer of exactly the same
5492 integer width. This leads to a family of functions such as
5493 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5494 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5495 suffix is required. Because the argument's type is matched against the return
5496 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5497
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5498<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5499 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5500
5501</div>
5502
5503<!-- ======================================================================= -->
5504<div class="doc_subsection">
5505 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5506</div>
5507
5508<div class="doc_text">
5509
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5510<p>Variable argument support is defined in LLVM with
5511 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5512 intrinsic functions. These functions are related to the similarly named
5513 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5514
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5515<p>All of these functions operate on arguments that use a target-specific value
5516 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5517 not define what this type is, so all transformations should be prepared to
5518 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5519
5520<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]5521 instruction and the variable argument handling intrinsic functions are
5522 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5523
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]5524<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5525define i32 @test(i32 %X, ...) {
5526 ; Initialize variable argument processing
5527 %ap = alloca i8*
5528 %ap2 = bitcast i8** %ap to i8*
5529 call void @llvm.va_start(i8* %ap2)
5530
5531 ; Read a single integer argument
5532 %tmp = va_arg i8** %ap, i32
5533
5534 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5535 %aq = alloca i8*
5536 %aq2 = bitcast i8** %aq to i8*
5537 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5538 call void @llvm.va_end(i8* %aq2)
5539
5540 ; Stop processing of arguments.
5541 call void @llvm.va_end(i8* %ap2)
5542 ret i32 %tmp
5543}
5544
5545declare void @llvm.va_start(i8*)
5546declare void @llvm.va_copy(i8*, i8*)
5547declare void @llvm.va_end(i8*)
5548</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5549
5550</div>
5551
5552<!-- _______________________________________________________________________ -->
5553<div class="doc_subsubsection">
5554 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5555</div>
5556
5557
5558<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5559
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5560<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5561<pre>
5562 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5563</pre>
5564
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5565<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5566<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5567 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]5568
5569<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5570<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]5571
5572<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5573<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]5574 macro available in C. In a target-dependent way, it initializes
5575 the <tt>va_list</tt> element to which the argument points, so that the next
5576 call to <tt>va_arg</tt> will produce the first variable argument passed to
5577 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5578 need to know the last argument of the function as the compiler can figure
5579 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5580
5581</div>
5582
5583<!-- _______________________________________________________________________ -->
5584<div class="doc_subsubsection">
5585 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5586</div>
5587
5588<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5589
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5590<h5>Syntax:</h5>
5591<pre>
5592 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5593</pre>
5594
5595<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5596<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5597 which has been initialized previously
5598 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5599 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5600
5601<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5602<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5603
5604<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5605<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]5606 macro available in C. In a target-dependent way, it destroys
5607 the <tt>va_list</tt> element to which the argument points. Calls
5608 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5609 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5610 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5611
5612</div>
5613
5614<!-- _______________________________________________________________________ -->
5615<div class="doc_subsubsection">
5616 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5617</div>
5618
5619<div class="doc_text">
5620
5621<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5622<pre>
5623 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5624</pre>
5625
5626<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5627<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5628 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5629
5630<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5631<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]5632 The second argument is a pointer to a <tt>va_list</tt> element to copy
5633 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5634
5635<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5636<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5637 macro available in C. In a target-dependent way, it copies the
5638 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5639 element. This intrinsic is necessary because
5640 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5641 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5642
5643</div>
5644
5645<!-- ======================================================================= -->
5646<div class="doc_subsection">
5647 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5648</div>
5649
5650<div class="doc_text">
5651
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5652<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5653Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5654intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5655roots on the stack</a>, as well as garbage collector implementations that
5656require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5657barriers. Front-ends for type-safe garbage collected languages should generate
5658these intrinsics to make use of the LLVM garbage collectors. For more details,
5659see <a href="GarbageCollection.html">Accurate Garbage Collection with
5660LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5661
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5662<p>The garbage collection intrinsics only operate on objects in the generic
5663 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5664
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5665</div>
5666
5667<!-- _______________________________________________________________________ -->
5668<div class="doc_subsubsection">
5669 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5670</div>
5671
5672<div class="doc_text">
5673
5674<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5675<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5676 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5677</pre>
5678
5679<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5680<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]5681 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5682
5683<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5684<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5685 root pointer. The second pointer (which must be either a constant or a
5686 global value address) contains the meta-data to be associated with the
5687 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5688
5689<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5690<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]5691 location. At compile-time, the code generator generates information to allow
5692 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5693 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5694 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5695
5696</div>
5697
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5698<!-- _______________________________________________________________________ -->
5699<div class="doc_subsubsection">
5700 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5701</div>
5702
5703<div class="doc_text">
5704
5705<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5706<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5707 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5708</pre>
5709
5710<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5711<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5712 locations, allowing garbage collector implementations that require read
5713 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5714
5715<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5716<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]5717 allocated from the garbage collector. The first object is a pointer to the
5718 start of the referenced object, if needed by the language runtime (otherwise
5719 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5720
5721<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5722<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5723 instruction, but may be replaced with substantially more complex code by the
5724 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5725 may only be used in a function which <a href="#gc">specifies a GC
5726 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5727
5728</div>
5729
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5730<!-- _______________________________________________________________________ -->
5731<div class="doc_subsubsection">
5732 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5733</div>
5734
5735<div class="doc_text">
5736
5737<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5738<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5739 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5740</pre>
5741
5742<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5743<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5744 locations, allowing garbage collector implementations that require write
5745 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5746
5747<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5748<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]5749 object to store it to, and the third is the address of the field of Obj to
5750 store to. If the runtime does not require a pointer to the object, Obj may
5751 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5752
5753<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5754<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5755 instruction, but may be replaced with substantially more complex code by the
5756 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5757 may only be used in a function which <a href="#gc">specifies a GC
5758 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5759
5760</div>
5761
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5762<!-- ======================================================================= -->
5763<div class="doc_subsection">
5764 <a name="int_codegen">Code Generator Intrinsics</a>
5765</div>
5766
5767<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5768
5769<p>These intrinsics are provided by LLVM to expose special features that may
5770 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5771
5772</div>
5773
5774<!-- _______________________________________________________________________ -->
5775<div class="doc_subsubsection">
5776 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5777</div>
5778
5779<div class="doc_text">
5780
5781<h5>Syntax:</h5>
5782<pre>
5783 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5784</pre>
5785
5786<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5787<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5788 target-specific value indicating the return address of the current function
5789 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5790
5791<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5792<p>The argument to this intrinsic indicates which function to return the address
5793 for. Zero indicates the calling function, one indicates its caller, etc.
5794 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5795
5796<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5797<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5798 indicating the return address of the specified call frame, or zero if it
5799 cannot be identified. The value returned by this intrinsic is likely to be
5800 incorrect or 0 for arguments other than zero, so it should only be used for
5801 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5802
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5803<p>Note that calling this intrinsic does not prevent function inlining or other
5804 aggressive transformations, so the value returned may not be that of the
5805 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5806
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5807</div>
5808
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5809<!-- _______________________________________________________________________ -->
5810<div class="doc_subsubsection">
5811 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5812</div>
5813
5814<div class="doc_text">
5815
5816<h5>Syntax:</h5>
5817<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]5818 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5819</pre>
5820
5821<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5822<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5823 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5824
5825<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5826<p>The argument to this intrinsic indicates which function to return the frame
5827 pointer for. Zero indicates the calling function, one indicates its caller,
5828 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5829
5830<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5831<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5832 indicating the frame address of the specified call frame, or zero if it
5833 cannot be identified. The value returned by this intrinsic is likely to be
5834 incorrect or 0 for arguments other than zero, so it should only be used for
5835 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5836
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5837<p>Note that calling this intrinsic does not prevent function inlining or other
5838 aggressive transformations, so the value returned may not be that of the
5839 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5840
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5841</div>
5842
5843<!-- _______________________________________________________________________ -->
5844<div class="doc_subsubsection">
5845 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5846</div>
5847
5848<div class="doc_text">
5849
5850<h5>Syntax:</h5>
5851<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]5852 declare i8* @llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5853</pre>
5854
5855<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5856<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5857 of the function stack, for use
5858 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5859 useful for implementing language features like scoped automatic variable
5860 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5861
5862<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5863<p>This intrinsic returns a opaque pointer value that can be passed
5864 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5865 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5866 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5867 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5868 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5869 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5870
5871</div>
5872
5873<!-- _______________________________________________________________________ -->
5874<div class="doc_subsubsection">
5875 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5876</div>
5877
5878<div class="doc_text">
5879
5880<h5>Syntax:</h5>
5881<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]5882 declare void @llvm.stackrestore(i8* %ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5883</pre>
5884
5885<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5886<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5887 the function stack to the state it was in when the
5888 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5889 executed. This is useful for implementing language features like scoped
5890 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5891
5892<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5893<p>See the description
5894 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5895
5896</div>
5897
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5898<!-- _______________________________________________________________________ -->
5899<div class="doc_subsubsection">
5900 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5901</div>
5902
5903<div class="doc_text">
5904
5905<h5>Syntax:</h5>
5906<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5907 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]5908</pre>
5909
5910<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5911<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5912 insert a prefetch instruction if supported; otherwise, it is a noop.
5913 Prefetches have no effect on the behavior of the program but can change its
5914 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5915
5916<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5917<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5918 specifier determining if the fetch should be for a read (0) or write (1),
5919 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5920 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5921 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5922
5923<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5924<p>This intrinsic does not modify the behavior of the program. In particular,
5925 prefetches cannot trap and do not produce a value. On targets that support
5926 this intrinsic, the prefetch can provide hints to the processor cache for
5927 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5928
5929</div>
5930
5931<!-- _______________________________________________________________________ -->
5932<div class="doc_subsubsection">
5933 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5934</div>
5935
5936<div class="doc_text">
5937
5938<h5>Syntax:</h5>
5939<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5940 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5941</pre>
5942
5943<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5944<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5945 Counter (PC) in a region of code to simulators and other tools. The method
5946 is target specific, but it is expected that the marker will use exported
5947 symbols to transmit the PC of the marker. The marker makes no guarantees
5948 that it will remain with any specific instruction after optimizations. It is
5949 possible that the presence of a marker will inhibit optimizations. The
5950 intended use is to be inserted after optimizations to allow correlations of
5951 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5952
5953<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5954<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5955
5956<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5957<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5958 not support this intrinsic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5959
5960</div>
5961
5962<!-- _______________________________________________________________________ -->
5963<div class="doc_subsubsection">
5964 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5965</div>
5966
5967<div class="doc_text">
5968
5969<h5>Syntax:</h5>
5970<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]5971 declare i64 @llvm.readcyclecounter()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5972</pre>
5973
5974<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5975<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5976 counter register (or similar low latency, high accuracy clocks) on those
5977 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5978 should map to RPCC. As the backing counters overflow quickly (on the order
5979 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5980
5981<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5982<p>When directly supported, reading the cycle counter should not modify any
5983 memory. Implementations are allowed to either return a application specific
5984 value or a system wide value. On backends without support, this is lowered
5985 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5986
5987</div>
5988
5989<!-- ======================================================================= -->
5990<div class="doc_subsection">
5991 <a name="int_libc">Standard C Library Intrinsics</a>
5992</div>
5993
5994<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5995
5996<p>LLVM provides intrinsics for a few important standard C library functions.
5997 These intrinsics allow source-language front-ends to pass information about
5998 the alignment of the pointer arguments to the code generator, providing
5999 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6000
6001</div>
6002
6003<!-- _______________________________________________________________________ -->
6004<div class="doc_subsubsection">
6005 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
6006</div>
6007
6008<div class="doc_text">
6009
6010<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6011<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]6012 integer bit width and for different address spaces. Not all targets support
6013 all bit widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6014
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6015<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6016 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6017 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6018 declare void @llvm.memcpy.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6019 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6020</pre>
6021
6022<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6023<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6024 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6025
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6026<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6027 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6028 and the pointers can be in specified address spaces.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6029
6030<h5>Arguments:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6031
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6032<p>The first argument is a pointer to the destination, the second is a pointer
6033 to the source. The third argument is an integer argument specifying the
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6034 number of bytes to copy, the fourth argument is the alignment of the
6035 source and destination locations, and the fifth is a boolean indicating a
6036 volatile access.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6037
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6038<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]6039 then the caller guarantees that both the source and destination pointers are
6040 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6041
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]6042<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6043 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6044 The detailed access behavior is not very cleanly specified and it is unwise
6045 to depend on it.</p>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6046
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6047<h5>Semantics:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6048
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6049<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6050 source location to the destination location, which are not allowed to
6051 overlap. It copies "len" bytes of memory over. If the argument is known to
6052 be aligned to some boundary, this can be specified as the fourth argument,
6053 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6054
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6055</div>
6056
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6057<!-- _______________________________________________________________________ -->
6058<div class="doc_subsubsection">
6059 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
6060</div>
6061
6062<div class="doc_text">
6063
6064<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]6065<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]6066 width and for different address space. Not all targets support all bit
6067 widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6068
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6069<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6070 declare void @llvm.memmove.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6071 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6072 declare void @llvm.memmove.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6073 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6074</pre>
6075
6076<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6077<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6078 source location to the destination location. It is similar to the
6079 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6080 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6081
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6082<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6083 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6084 and the pointers can be in specified address spaces.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6085
6086<h5>Arguments:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6087
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6088<p>The first argument is a pointer to the destination, the second is a pointer
6089 to the source. The third argument is an integer argument specifying the
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6090 number of bytes to copy, the fourth argument is the alignment of the
6091 source and destination locations, and the fifth is a boolean indicating a
6092 volatile access.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6093
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6094<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]6095 then the caller guarantees that the source and destination pointers are
6096 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6097
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]6098<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6099 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6100 The detailed access behavior is not very cleanly specified and it is unwise
6101 to depend on it.</p>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6102
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6103<h5>Semantics:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6104
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6105<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6106 source location to the destination location, which may overlap. It copies
6107 "len" bytes of memory over. If the argument is known to be aligned to some
6108 boundary, this can be specified as the fourth argument, otherwise it should
6109 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6110
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6111</div>
6112
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6113<!-- _______________________________________________________________________ -->
6114<div class="doc_subsubsection">
6115 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
6116</div>
6117
6118<div class="doc_text">
6119
6120<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]6121<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]6122 width and for different address spaces. Not all targets support all bit
6123 widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6124
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6125<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6126 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerc0dfafe2010-04-08 00:54:34 +0000[diff] [blame]6127 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6128 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerc0dfafe2010-04-08 00:54:34 +0000[diff] [blame]6129 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6130</pre>
6131
6132<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6133<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6134 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6135
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6136<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6137 intrinsic does not return a value, takes extra alignment/volatile arguments,
6138 and the destination can be in an arbitrary address space.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6139
6140<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6141<p>The first argument is a pointer to the destination to fill, the second is the
6142 byte value to fill it with, the third argument is an integer argument
6143 specifying the number of bytes to fill, and the fourth argument is the known
6144 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6145
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6146<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]6147 then the caller guarantees that the destination pointer is aligned to that
6148 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6149
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]6150<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6151 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6152 The detailed access behavior is not very cleanly specified and it is unwise
6153 to depend on it.</p>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6154
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6155<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6156<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6157 at the destination location. If the argument is known to be aligned to some
6158 boundary, this can be specified as the fourth argument, otherwise it should
6159 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6160
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6161</div>
6162
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6163<!-- _______________________________________________________________________ -->
6164<div class="doc_subsubsection">
6165 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
6166</div>
6167
6168<div class="doc_text">
6169
6170<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6171<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6172 floating point or vector of floating point type. Not all targets support all
6173 types however.</p>
6174
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6175<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]6176 declare float @llvm.sqrt.f32(float %Val)
6177 declare double @llvm.sqrt.f64(double %Val)
6178 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6179 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6180 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6181</pre>
6182
6183<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6184<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6185 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6186 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6187 behavior for negative numbers other than -0.0 (which allows for better
6188 optimization, because there is no need to worry about errno being
6189 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]6190
6191<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6192<p>The argument and return value are floating point numbers of the same
6193 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6194
6195<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6196<p>This function returns the sqrt of the specified operand if it is a
6197 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6198
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6199</div>
6200
6201<!-- _______________________________________________________________________ -->
6202<div class="doc_subsubsection">
6203 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
6204</div>
6205
6206<div class="doc_text">
6207
6208<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6209<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6210 floating point or vector of floating point type. Not all targets support all
6211 types however.</p>
6212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6213<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]6214 declare float @llvm.powi.f32(float %Val, i32 %power)
6215 declare double @llvm.powi.f64(double %Val, i32 %power)
6216 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6217 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6218 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6219</pre>
6220
6221<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6222<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6223 specified (positive or negative) power. The order of evaluation of
6224 multiplications is not defined. When a vector of floating point type is
6225 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6226
6227<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6228<p>The second argument is an integer power, and the first is a value to raise to
6229 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6230
6231<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6232<p>This function returns the first value raised to the second power with an
6233 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6234
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6235</div>
6236
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6237<!-- _______________________________________________________________________ -->
6238<div class="doc_subsubsection">
6239 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6240</div>
6241
6242<div class="doc_text">
6243
6244<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6245<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6246 floating point or vector of floating point type. Not all targets support all
6247 types however.</p>
6248
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6249<pre>
6250 declare float @llvm.sin.f32(float %Val)
6251 declare double @llvm.sin.f64(double %Val)
6252 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6253 declare fp128 @llvm.sin.f128(fp128 %Val)
6254 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6255</pre>
6256
6257<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6258<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6259
6260<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6261<p>The argument and return value are floating point numbers of the same
6262 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6263
6264<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6265<p>This function returns the sine of the specified operand, returning the same
6266 values as the libm <tt>sin</tt> functions would, and handles error conditions
6267 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6268
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6269</div>
6270
6271<!-- _______________________________________________________________________ -->
6272<div class="doc_subsubsection">
6273 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6274</div>
6275
6276<div class="doc_text">
6277
6278<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6279<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6280 floating point or vector of floating point type. Not all targets support all
6281 types however.</p>
6282
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6283<pre>
6284 declare float @llvm.cos.f32(float %Val)
6285 declare double @llvm.cos.f64(double %Val)
6286 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6287 declare fp128 @llvm.cos.f128(fp128 %Val)
6288 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6289</pre>
6290
6291<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6292<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6293
6294<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6295<p>The argument and return value are floating point numbers of the same
6296 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6297
6298<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6299<p>This function returns the cosine of the specified operand, returning the same
6300 values as the libm <tt>cos</tt> functions would, and handles error conditions
6301 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6302
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6303</div>
6304
6305<!-- _______________________________________________________________________ -->
6306<div class="doc_subsubsection">
6307 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6308</div>
6309
6310<div class="doc_text">
6311
6312<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6313<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6314 floating point or vector of floating point type. Not all targets support all
6315 types however.</p>
6316
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6317<pre>
6318 declare float @llvm.pow.f32(float %Val, float %Power)
6319 declare double @llvm.pow.f64(double %Val, double %Power)
6320 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6321 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6322 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6323</pre>
6324
6325<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6326<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6327 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6328
6329<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6330<p>The second argument is a floating point power, and the first is a value to
6331 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6332
6333<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6334<p>This function returns the first value raised to the second power, returning
6335 the same values as the libm <tt>pow</tt> functions would, and handles error
6336 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6337
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6338</div>
6339
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6340<!-- ======================================================================= -->
6341<div class="doc_subsection">
6342 <a name="int_manip">Bit Manipulation Intrinsics</a>
6343</div>
6344
6345<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6346
6347<p>LLVM provides intrinsics for a few important bit manipulation operations.
6348 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6349
6350</div>
6351
6352<!-- _______________________________________________________________________ -->
6353<div class="doc_subsubsection">
6354 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
6355</div>
6356
6357<div class="doc_text">
6358
6359<h5>Syntax:</h5>
6360<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6361 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6362
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6363<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6364 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6365 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6366 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6367</pre>
6368
6369<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6370<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6371 values with an even number of bytes (positive multiple of 16 bits). These
6372 are useful for performing operations on data that is not in the target's
6373 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6374
6375<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6376<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6377 and low byte of the input i16 swapped. Similarly,
6378 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6379 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6380 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6381 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6382 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6383 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6384
6385</div>
6386
6387<!-- _______________________________________________________________________ -->
6388<div class="doc_subsubsection">
6389 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6390</div>
6391
6392<div class="doc_text">
6393
6394<h5>Syntax:</h5>
6395<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]6396 width. Not all targets support all bit widths however.</p>
6397
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6398<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6399 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6400 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6401 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6402 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6403 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6404</pre>
6405
6406<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6407<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6408 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6409
6410<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6411<p>The only argument is the value to be counted. The argument may be of any
6412 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6413
6414<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6415<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]6416
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6417</div>
6418
6419<!-- _______________________________________________________________________ -->
6420<div class="doc_subsubsection">
6421 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6422</div>
6423
6424<div class="doc_text">
6425
6426<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6427<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6428 integer bit width. Not all targets support all bit widths however.</p>
6429
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6430<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6431 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6432 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6433 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6434 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6435 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6436</pre>
6437
6438<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6439<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6440 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6441
6442<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6443<p>The only argument is the value to be counted. The argument may be of any
6444 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6445
6446<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6447<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6448 zeros in a variable. If the src == 0 then the result is the size in bits of
6449 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6450
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6451</div>
6452
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6453<!-- _______________________________________________________________________ -->
6454<div class="doc_subsubsection">
6455 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6456</div>
6457
6458<div class="doc_text">
6459
6460<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6461<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6462 integer bit width. Not all targets support all bit widths however.</p>
6463
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6464<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6465 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6466 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6467 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6468 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6469 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6470</pre>
6471
6472<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6473<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6474 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6475
6476<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6477<p>The only argument is the value to be counted. The argument may be of any
6478 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6479
6480<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6481<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6482 zeros in a variable. If the src == 0 then the result is the size in bits of
6483 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6484
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6485</div>
6486
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6487<!-- ======================================================================= -->
6488<div class="doc_subsection">
6489 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6490</div>
6491
6492<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6493
6494<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6495
6496</div>
6497
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6498<!-- _______________________________________________________________________ -->
6499<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6500 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6501</div>
6502
6503<div class="doc_text">
6504
6505<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6506<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]6507 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6508
6509<pre>
6510 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6511 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6512 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6513</pre>
6514
6515<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6516<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6517 a signed addition of the two arguments, and indicate whether an overflow
6518 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6519
6520<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6521<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]6522 be of integer types of any bit width, but they must have the same bit
6523 width. The second element of the result structure must be of
6524 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6525 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6526
6527<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6528<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6529 a signed addition of the two variables. They return a structure &mdash; the
6530 first element of which is the signed summation, and the second element of
6531 which is a bit specifying if the signed summation resulted in an
6532 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6533
6534<h5>Examples:</h5>
6535<pre>
6536 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6537 %sum = extractvalue {i32, i1} %res, 0
6538 %obit = extractvalue {i32, i1} %res, 1
6539 br i1 %obit, label %overflow, label %normal
6540</pre>
6541
6542</div>
6543
6544<!-- _______________________________________________________________________ -->
6545<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6546 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6547</div>
6548
6549<div class="doc_text">
6550
6551<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6552<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]6553 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6554
6555<pre>
6556 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6557 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6558 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6559</pre>
6560
6561<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6562<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6563 an unsigned addition of the two arguments, and indicate whether a carry
6564 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6565
6566<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6567<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]6568 be of integer types of any bit width, but they must have the same bit
6569 width. The second element of the result structure must be of
6570 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6571 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6572
6573<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6574<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6575 an unsigned addition of the two arguments. They return a structure &mdash;
6576 the first element of which is the sum, and the second element of which is a
6577 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6578
6579<h5>Examples:</h5>
6580<pre>
6581 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6582 %sum = extractvalue {i32, i1} %res, 0
6583 %obit = extractvalue {i32, i1} %res, 1
6584 br i1 %obit, label %carry, label %normal
6585</pre>
6586
6587</div>
6588
6589<!-- _______________________________________________________________________ -->
6590<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6591 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6592</div>
6593
6594<div class="doc_text">
6595
6596<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6597<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6598 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6599
6600<pre>
6601 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6602 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6603 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6604</pre>
6605
6606<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6607<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6608 a signed subtraction of the two arguments, and indicate whether an overflow
6609 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6610
6611<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6612<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]6613 be of integer types of any bit width, but they must have the same bit
6614 width. The second element of the result structure must be of
6615 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6616 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6617
6618<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6619<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6620 a signed subtraction of the two arguments. They return a structure &mdash;
6621 the first element of which is the subtraction, and the second element of
6622 which is a bit specifying if the signed subtraction resulted in an
6623 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6624
6625<h5>Examples:</h5>
6626<pre>
6627 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6628 %sum = extractvalue {i32, i1} %res, 0
6629 %obit = extractvalue {i32, i1} %res, 1
6630 br i1 %obit, label %overflow, label %normal
6631</pre>
6632
6633</div>
6634
6635<!-- _______________________________________________________________________ -->
6636<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6637 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6638</div>
6639
6640<div class="doc_text">
6641
6642<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6643<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]6644 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6645
6646<pre>
6647 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6648 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6649 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6650</pre>
6651
6652<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6653<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6654 an unsigned subtraction of the two arguments, and indicate whether an
6655 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6656
6657<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6658<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]6659 be of integer types of any bit width, but they must have the same bit
6660 width. The second element of the result structure must be of
6661 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6662 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6663
6664<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6665<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6666 an unsigned subtraction of the two arguments. They return a structure &mdash;
6667 the first element of which is the subtraction, and the second element of
6668 which is a bit specifying if the unsigned subtraction resulted in an
6669 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6670
6671<h5>Examples:</h5>
6672<pre>
6673 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6674 %sum = extractvalue {i32, i1} %res, 0
6675 %obit = extractvalue {i32, i1} %res, 1
6676 br i1 %obit, label %overflow, label %normal
6677</pre>
6678
6679</div>
6680
6681<!-- _______________________________________________________________________ -->
6682<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6683 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6684</div>
6685
6686<div class="doc_text">
6687
6688<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6689<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]6690 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6691
6692<pre>
6693 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6694 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6695 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6696</pre>
6697
6698<h5>Overview:</h5>
6699
6700<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6701 a signed multiplication of the two arguments, and indicate whether an
6702 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6703
6704<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6705<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]6706 be of integer types of any bit width, but they must have the same bit
6707 width. The second element of the result structure must be of
6708 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6709 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6710
6711<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6712<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6713 a signed multiplication of the two arguments. They return a structure &mdash;
6714 the first element of which is the multiplication, and the second element of
6715 which is a bit specifying if the signed multiplication resulted in an
6716 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6717
6718<h5>Examples:</h5>
6719<pre>
6720 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6721 %sum = extractvalue {i32, i1} %res, 0
6722 %obit = extractvalue {i32, i1} %res, 1
6723 br i1 %obit, label %overflow, label %normal
6724</pre>
6725
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6726</div>
6727
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6728<!-- _______________________________________________________________________ -->
6729<div class="doc_subsubsection">
6730 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6731</div>
6732
6733<div class="doc_text">
6734
6735<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6736<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]6737 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6738
6739<pre>
6740 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6741 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6742 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6743</pre>
6744
6745<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6746<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6747 a unsigned multiplication of the two arguments, and indicate whether an
6748 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6749
6750<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6751<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]6752 be of integer types of any bit width, but they must have the same bit
6753 width. The second element of the result structure must be of
6754 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6755 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6756
6757<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6758<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6759 an unsigned multiplication of the two arguments. They return a structure
6760 &mdash; the first element of which is the multiplication, and the second
6761 element of which is a bit specifying if the unsigned multiplication resulted
6762 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6763
6764<h5>Examples:</h5>
6765<pre>
6766 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6767 %sum = extractvalue {i32, i1} %res, 0
6768 %obit = extractvalue {i32, i1} %res, 1
6769 br i1 %obit, label %overflow, label %normal
6770</pre>
6771
6772</div>
6773
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6774<!-- ======================================================================= -->
6775<div class="doc_subsection">
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6776 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6777</div>
6778
6779<div class="doc_text">
6780
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6781<p>Half precision floating point is a storage-only format. This means that it is
6782 a dense encoding (in memory) but does not support computation in the
6783 format.</p>
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6784
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6785<p>This means that code must first load the half-precision floating point
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6786 value as an i16, then convert it to float with <a
6787 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6788 Computation can then be performed on the float value (including extending to
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6789 double etc). To store the value back to memory, it is first converted to
6790 float if needed, then converted to i16 with
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6791 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6792 storing as an i16 value.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6793</div>
6794
6795<!-- _______________________________________________________________________ -->
6796<div class="doc_subsubsection">
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6797 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6798</div>
6799
6800<div class="doc_text">
6801
6802<h5>Syntax:</h5>
6803<pre>
6804 declare i16 @llvm.convert.to.fp16(f32 %a)
6805</pre>
6806
6807<h5>Overview:</h5>
6808<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6809 a conversion from single precision floating point format to half precision
6810 floating point format.</p>
6811
6812<h5>Arguments:</h5>
6813<p>The intrinsic function contains single argument - the value to be
6814 converted.</p>
6815
6816<h5>Semantics:</h5>
6817<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6818 a conversion from single precision floating point format to half precision
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6819 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6820 contains the converted number.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6821
6822<h5>Examples:</h5>
6823<pre>
6824 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6825 store i16 %res, i16* @x, align 2
6826</pre>
6827
6828</div>
6829
6830<!-- _______________________________________________________________________ -->
6831<div class="doc_subsubsection">
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6832 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6833</div>
6834
6835<div class="doc_text">
6836
6837<h5>Syntax:</h5>
6838<pre>
6839 declare f32 @llvm.convert.from.fp16(i16 %a)
6840</pre>
6841
6842<h5>Overview:</h5>
6843<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6844 a conversion from half precision floating point format to single precision
6845 floating point format.</p>
6846
6847<h5>Arguments:</h5>
6848<p>The intrinsic function contains single argument - the value to be
6849 converted.</p>
6850
6851<h5>Semantics:</h5>
6852<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6853 conversion from half single precision floating point format to single
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6854 precision floating point format. The input half-float value is represented by
6855 an <tt>i16</tt> value.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6856
6857<h5>Examples:</h5>
6858<pre>
6859 %a = load i16* @x, align 2
6860 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6861</pre>
6862
6863</div>
6864
6865<!-- ======================================================================= -->
6866<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6867 <a name="int_debugger">Debugger Intrinsics</a>
6868</div>
6869
6870<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6871
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6872<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6873 prefix), are described in
6874 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6875 Level Debugging</a> document.</p>
6876
6877</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6878
6879<!-- ======================================================================= -->
6880<div class="doc_subsection">
6881 <a name="int_eh">Exception Handling Intrinsics</a>
6882</div>
6883
6884<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6885
6886<p>The LLVM exception handling intrinsics (which all start with
6887 <tt>llvm.eh.</tt> prefix), are described in
6888 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6889 Handling</a> document.</p>
6890
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6891</div>
6892
6893<!-- ======================================================================= -->
6894<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6895 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6896</div>
6897
6898<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6899
6900<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanbd2f9ba2010-07-02 23:18:08 +0000[diff] [blame]6901 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6902 The result is a callable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6903 function pointer lacking the nest parameter - the caller does not need to
6904 provide a value for it. Instead, the value to use is stored in advance in a
6905 "trampoline", a block of memory usually allocated on the stack, which also
6906 contains code to splice the nest value into the argument list. This is used
6907 to implement the GCC nested function address extension.</p>
6908
6909<p>For example, if the function is
6910 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6911 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6912 follows:</p>
6913
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]6914<pre class="doc_code">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6915 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6916 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]6917 %p = call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval)
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6918 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6919</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6920
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]6921<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6922 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6923
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6924</div>
6925
6926<!-- _______________________________________________________________________ -->
6927<div class="doc_subsubsection">
6928 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6929</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6930
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6931<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6932
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6933<h5>Syntax:</h5>
6934<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6935 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]6936</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6937
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6938<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6939<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6940 function pointer suitable for executing it.</p>
6941
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6942<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6943<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6944 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6945 sufficiently aligned block of memory; this memory is written to by the
6946 intrinsic. Note that the size and the alignment are target-specific - LLVM
6947 currently provides no portable way of determining them, so a front-end that
6948 generates this intrinsic needs to have some target-specific knowledge.
6949 The <tt>func</tt> argument must hold a function bitcast to
6950 an <tt>i8*</tt>.</p>
6951
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6952<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6953<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6954 dependent code, turning it into a function. A pointer to this function is
6955 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6956 function pointer type</a> before being called. The new function's signature
6957 is the same as that of <tt>func</tt> with any arguments marked with
6958 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6959 is allowed, and it must be of pointer type. Calling the new function is
6960 equivalent to calling <tt>func</tt> with the same argument list, but
6961 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6962 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6963 by <tt>tramp</tt> is modified, then the effect of any later call to the
6964 returned function pointer is undefined.</p>
6965
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6966</div>
6967
6968<!-- ======================================================================= -->
6969<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6970 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6971</div>
6972
6973<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6974
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6975<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6976 hardware constructs for atomic operations and memory synchronization. This
6977 provides an interface to the hardware, not an interface to the programmer. It
6978 is aimed at a low enough level to allow any programming models or APIs
6979 (Application Programming Interfaces) which need atomic behaviors to map
6980 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6981 hardware provides a "universal IR" for source languages, it also provides a
6982 starting point for developing a "universal" atomic operation and
6983 synchronization IR.</p>
6984
6985<p>These do <em>not</em> form an API such as high-level threading libraries,
6986 software transaction memory systems, atomic primitives, and intrinsic
6987 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6988 application libraries. The hardware interface provided by LLVM should allow
6989 a clean implementation of all of these APIs and parallel programming models.
6990 No one model or paradigm should be selected above others unless the hardware
6991 itself ubiquitously does so.</p>
6992
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6993</div>
6994
6995<!-- _______________________________________________________________________ -->
6996<div class="doc_subsubsection">
6997 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6998</div>
6999<div class="doc_text">
7000<h5>Syntax:</h5>
7001<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7002 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]7003</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7004
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7005<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7006<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7007 specific pairs of memory access types.</p>
7008
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7009<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7010<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7011 The first four arguments enables a specific barrier as listed below. The
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]7012 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7013 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7014
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7015<ul>
7016 <li><tt>ll</tt>: load-load barrier</li>
7017 <li><tt>ls</tt>: load-store barrier</li>
7018 <li><tt>sl</tt>: store-load barrier</li>
7019 <li><tt>ss</tt>: store-store barrier</li>
7020 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7021</ul>
7022
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7023<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7024<p>This intrinsic causes the system to enforce some ordering constraints upon
7025 the loads and stores of the program. This barrier does not
7026 indicate <em>when</em> any events will occur, it only enforces
7027 an <em>order</em> in which they occur. For any of the specified pairs of load
7028 and store operations (f.ex. load-load, or store-load), all of the first
7029 operations preceding the barrier will complete before any of the second
7030 operations succeeding the barrier begin. Specifically the semantics for each
7031 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7032
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7033<ul>
7034 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7035 after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7036 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7037 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7038 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7039 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7040 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7041 load after the barrier begins.</li>
7042</ul>
7043
7044<p>These semantics are applied with a logical "and" behavior when more than one
7045 is enabled in a single memory barrier intrinsic.</p>
7046
7047<p>Backends may implement stronger barriers than those requested when they do
7048 not support as fine grained a barrier as requested. Some architectures do
7049 not need all types of barriers and on such architectures, these become
7050 noops.</p>
7051
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7052<h5>Example:</h5>
7053<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7054%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7055%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7056 store i32 4, %ptr
7057
7058%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7059 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7060 <i>; guarantee the above finishes</i>
7061 store i32 8, %ptr <i>; before this begins</i>
7062</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7063
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7064</div>
7065
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7066<!-- _______________________________________________________________________ -->
7067<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7068 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7069</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7070
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7071<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7072
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7073<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7074<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7075 any integer bit width and for different address spaces. Not all targets
7076 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7077
7078<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7079 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7080 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7081 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7082 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]7083</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7084
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7085<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7086<p>This loads a value in memory and compares it to a given value. If they are
7087 equal, it stores a new value into the memory.</p>
7088
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7089<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7090<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7091 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7092 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7093 this integer type. While any bit width integer may be used, targets may only
7094 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7095
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7096<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7097<p>This entire intrinsic must be executed atomically. It first loads the value
7098 in memory pointed to by <tt>ptr</tt> and compares it with the
7099 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7100 memory. The loaded value is yielded in all cases. This provides the
7101 equivalent of an atomic compare-and-swap operation within the SSA
7102 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7103
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7104<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7105<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7106%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7107%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7108 store i32 4, %ptr
7109
7110%val1 = add i32 4, 4
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7111%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7112 <i>; yields {i32}:result1 = 4</i>
7113%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7114%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7115
7116%val2 = add i32 1, 1
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7117%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7118 <i>; yields {i32}:result2 = 8</i>
7119%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7120
7121%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7122</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7123
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7124</div>
7125
7126<!-- _______________________________________________________________________ -->
7127<div class="doc_subsubsection">
7128 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7129</div>
7130<div class="doc_text">
7131<h5>Syntax:</h5>
7132
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7133<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7134 integer bit width. Not all targets support all bit widths however.</p>
7135
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7136<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7137 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7138 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7139 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7140 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]7141</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7142
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7143<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7144<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7145 the value from memory. It then stores the value in <tt>val</tt> in the memory
7146 at <tt>ptr</tt>.</p>
7147
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7148<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7149<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7150 the <tt>val</tt> argument and the result must be integers of the same bit
7151 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7152 integer type. The targets may only lower integer representations they
7153 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7154
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7155<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7156<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7157 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7158 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7159
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7160<h5>Examples:</h5>
7161<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7162%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7163%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7164 store i32 4, %ptr
7165
7166%val1 = add i32 4, 4
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7167%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7168 <i>; yields {i32}:result1 = 4</i>
7169%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7170%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7171
7172%val2 = add i32 1, 1
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7173%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7174 <i>; yields {i32}:result2 = 8</i>
7175
7176%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7177%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7178</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7179
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7180</div>
7181
7182<!-- _______________________________________________________________________ -->
7183<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7184 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7185
7186</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7187
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7188<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7189
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7190<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7191<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7192 any integer bit width. Not all targets support all bit widths however.</p>
7193
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7194<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7195 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7196 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7197 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7198 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]7199</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7200
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7201<h5>Overview:</h5>
7202<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7203 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7204
7205<h5>Arguments:</h5>
7206<p>The intrinsic takes two arguments, the first a pointer to an integer value
7207 and the second an integer value. The result is also an integer value. These
7208 integer types can have any bit width, but they must all have the same bit
7209 width. The targets may only lower integer representations they support.</p>
7210
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7211<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7212<p>This intrinsic does a series of operations atomically. It first loads the
7213 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7214 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]7215
7216<h5>Examples:</h5>
7217<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7218%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7219%ptr = bitcast i8* %mallocP to i32*
7220 store i32 4, %ptr
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7221%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7222 <i>; yields {i32}:result1 = 4</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7223%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7224 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7225%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7226 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7227%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7228</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7229
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7230</div>
7231
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7232<!-- _______________________________________________________________________ -->
7233<div class="doc_subsubsection">
7234 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7235
7236</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7237
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7238<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7239
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7240<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7241<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7242 any integer bit width and for different address spaces. Not all targets
7243 support all bit widths however.</p>
7244
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7245<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7246 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7247 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7248 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7249 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]7250</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7251
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7252<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7253<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7254 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7255
7256<h5>Arguments:</h5>
7257<p>The intrinsic takes two arguments, the first a pointer to an integer value
7258 and the second an integer value. The result is also an integer value. These
7259 integer types can have any bit width, but they must all have the same bit
7260 width. The targets may only lower integer representations they support.</p>
7261
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7262<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7263<p>This intrinsic does a series of operations atomically. It first loads the
7264 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7265 result to <tt>ptr</tt>. It yields the original value stored
7266 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7267
7268<h5>Examples:</h5>
7269<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7270%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7271%ptr = bitcast i8* %mallocP to i32*
7272 store i32 8, %ptr
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7273%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7274 <i>; yields {i32}:result1 = 8</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7275%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7276 <i>; yields {i32}:result2 = 4</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7277%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7278 <i>; yields {i32}:result3 = 2</i>
7279%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7280</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7281
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7282</div>
7283
7284<!-- _______________________________________________________________________ -->
7285<div class="doc_subsubsection">
7286 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7287 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7288 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7289 <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]7290</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7291
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7292<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7293
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7294<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7295<p>These are overloaded intrinsics. You can
7296 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7297 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7298 bit width and for different address spaces. Not all targets support all bit
7299 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7300
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7301<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7302 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7303 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7304 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7305 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]7306</pre>
7307
7308<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7309 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7310 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7311 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7312 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]7313</pre>
7314
7315<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7316 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7317 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7318 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7319 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]7320</pre>
7321
7322<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7323 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7324 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7325 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7326 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]7327</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7328
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7329<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7330<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7331 the value stored in memory at <tt>ptr</tt>. It yields the original value
7332 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7333
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7334<h5>Arguments:</h5>
7335<p>These intrinsics take two arguments, the first a pointer to an integer value
7336 and the second an integer value. The result is also an integer value. These
7337 integer types can have any bit width, but they must all have the same bit
7338 width. The targets may only lower integer representations they support.</p>
7339
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7340<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7341<p>These intrinsics does a series of operations atomically. They first load the
7342 value stored at <tt>ptr</tt>. They then do the bitwise
7343 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7344 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7345
7346<h5>Examples:</h5>
7347<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7348%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7349%ptr = bitcast i8* %mallocP to i32*
7350 store i32 0x0F0F, %ptr
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7351%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7352 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7353%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7354 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7355%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7356 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7357%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7358 <i>; yields {i32}:result3 = FF</i>
7359%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7360</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7361
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7362</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7363
7364<!-- _______________________________________________________________________ -->
7365<div class="doc_subsubsection">
7366 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7367 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7368 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7369 <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]7370</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7371
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7372<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7373
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7374<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7375<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7376 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7377 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7378 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7379
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7380<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7381 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7382 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7383 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7384 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]7385</pre>
7386
7387<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7388 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7389 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7390 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7391 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]7392</pre>
7393
7394<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7395 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7396 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7397 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7398 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]7399</pre>
7400
7401<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7402 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7403 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7404 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7405 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]7406</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7407
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7408<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7409<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7410 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7411 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7412
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7413<h5>Arguments:</h5>
7414<p>These intrinsics take two arguments, the first a pointer to an integer value
7415 and the second an integer value. The result is also an integer value. These
7416 integer types can have any bit width, but they must all have the same bit
7417 width. The targets may only lower integer representations they support.</p>
7418
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7419<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7420<p>These intrinsics does a series of operations atomically. They first load the
7421 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7422 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7423 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7424
7425<h5>Examples:</h5>
7426<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7427%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7428%ptr = bitcast i8* %mallocP to i32*
7429 store i32 7, %ptr
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7430%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7431 <i>; yields {i32}:result0 = 7</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7432%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7433 <i>; yields {i32}:result1 = -2</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7434%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7435 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7436%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7437 <i>; yields {i32}:result3 = 8</i>
7438%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7439</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7440
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7441</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7442
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7443
7444<!-- ======================================================================= -->
7445<div class="doc_subsection">
7446 <a name="int_memorymarkers">Memory Use Markers</a>
7447</div>
7448
7449<div class="doc_text">
7450
7451<p>This class of intrinsics exists to information about the lifetime of memory
7452 objects and ranges where variables are immutable.</p>
7453
7454</div>
7455
7456<!-- _______________________________________________________________________ -->
7457<div class="doc_subsubsection">
7458 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7459</div>
7460
7461<div class="doc_text">
7462
7463<h5>Syntax:</h5>
7464<pre>
7465 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7466</pre>
7467
7468<h5>Overview:</h5>
7469<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7470 object's lifetime.</p>
7471
7472<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7473<p>The first argument is a constant integer representing the size of the
7474 object, or -1 if it is variable sized. The second argument is a pointer to
7475 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7476
7477<h5>Semantics:</h5>
7478<p>This intrinsic indicates that before this point in the code, the value of the
7479 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]7480 never be used and has an undefined value. A load from the pointer that
7481 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7482 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7483
7484</div>
7485
7486<!-- _______________________________________________________________________ -->
7487<div class="doc_subsubsection">
7488 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7489</div>
7490
7491<div class="doc_text">
7492
7493<h5>Syntax:</h5>
7494<pre>
7495 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7496</pre>
7497
7498<h5>Overview:</h5>
7499<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7500 object's lifetime.</p>
7501
7502<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7503<p>The first argument is a constant integer representing the size of the
7504 object, or -1 if it is variable sized. The second argument is a pointer to
7505 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7506
7507<h5>Semantics:</h5>
7508<p>This intrinsic indicates that after this point in the code, the value of the
7509 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7510 never be used and has an undefined value. Any stores into the memory object
7511 following this intrinsic may be removed as dead.
7512
7513</div>
7514
7515<!-- _______________________________________________________________________ -->
7516<div class="doc_subsubsection">
7517 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7518</div>
7519
7520<div class="doc_text">
7521
7522<h5>Syntax:</h5>
7523<pre>
7524 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7525</pre>
7526
7527<h5>Overview:</h5>
7528<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7529 a memory object will not change.</p>
7530
7531<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7532<p>The first argument is a constant integer representing the size of the
7533 object, or -1 if it is variable sized. The second argument is a pointer to
7534 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7535
7536<h5>Semantics:</h5>
7537<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7538 the return value, the referenced memory location is constant and
7539 unchanging.</p>
7540
7541</div>
7542
7543<!-- _______________________________________________________________________ -->
7544<div class="doc_subsubsection">
7545 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7546</div>
7547
7548<div class="doc_text">
7549
7550<h5>Syntax:</h5>
7551<pre>
7552 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7553</pre>
7554
7555<h5>Overview:</h5>
7556<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7557 a memory object are mutable.</p>
7558
7559<h5>Arguments:</h5>
7560<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7561 The second argument is a constant integer representing the size of the
7562 object, or -1 if it is variable sized and the third argument is a pointer
7563 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7564
7565<h5>Semantics:</h5>
7566<p>This intrinsic indicates that the memory is mutable again.</p>
7567
7568</div>
7569
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7570<!-- ======================================================================= -->
7571<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7572 <a name="int_general">General Intrinsics</a>
7573</div>
7574
7575<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7576
7577<p>This class of intrinsics is designed to be generic and has no specific
7578 purpose.</p>
7579
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7580</div>
7581
7582<!-- _______________________________________________________________________ -->
7583<div class="doc_subsubsection">
7584 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7585</div>
7586
7587<div class="doc_text">
7588
7589<h5>Syntax:</h5>
7590<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7591 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7592</pre>
7593
7594<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7595<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7596
7597<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7598<p>The first argument is a pointer to a value, the second is a pointer to a
7599 global string, the third is a pointer to a global string which is the source
7600 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7601
7602<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7603<p>This intrinsic allows annotation of local variables with arbitrary strings.
7604 This can be useful for special purpose optimizations that want to look for
7605 these annotations. These have no other defined use, they are ignored by code
7606 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7607
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7608</div>
7609
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7610<!-- _______________________________________________________________________ -->
7611<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7612 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7613</div>
7614
7615<div class="doc_text">
7616
7617<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7618<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7619 any integer bit width.</p>
7620
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7621<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7622 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7623 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7624 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7625 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7626 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]7627</pre>
7628
7629<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7630<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7631
7632<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7633<p>The first argument is an integer value (result of some expression), the
7634 second is a pointer to a global string, the third is a pointer to a global
7635 string which is the source file name, and the last argument is the line
7636 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7637
7638<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7639<p>This intrinsic allows annotations to be put on arbitrary expressions with
7640 arbitrary strings. This can be useful for special purpose optimizations that
7641 want to look for these annotations. These have no other defined use, they
7642 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7643
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7644</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7645
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7646<!-- _______________________________________________________________________ -->
7647<div class="doc_subsubsection">
7648 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7649</div>
7650
7651<div class="doc_text">
7652
7653<h5>Syntax:</h5>
7654<pre>
7655 declare void @llvm.trap()
7656</pre>
7657
7658<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7659<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7660
7661<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7662<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7663
7664<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7665<p>This intrinsics is lowered to the target dependent trap instruction. If the
7666 target does not have a trap instruction, this intrinsic will be lowered to
7667 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7668
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7669</div>
7670
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7671<!-- _______________________________________________________________________ -->
7672<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7673 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7674</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7675
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7676<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7677
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7678<h5>Syntax:</h5>
7679<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7680 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7681</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7682
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7683<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7684<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7685 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7686 ensure that it is placed on the stack before local variables.</p>
7687
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7688<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7689<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7690 arguments. The first argument is the value loaded from the stack
7691 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7692 that has enough space to hold the value of the guard.</p>
7693
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7694<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7695<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7696 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7697 stack. This is to ensure that if a local variable on the stack is
7698 overwritten, it will destroy the value of the guard. When the function exits,
7699 the guard on the stack is checked against the original guard. If they're
7700 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7701 function.</p>
7702
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7703</div>
7704
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7705<!-- _______________________________________________________________________ -->
7706<div class="doc_subsubsection">
7707 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7708</div>
7709
7710<div class="doc_text">
7711
7712<h5>Syntax:</h5>
7713<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7714 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7715 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7716</pre>
7717
7718<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7719<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher184f44d2010-01-08 21:42:39 +0000[diff] [blame]7720 to the optimizers to discover at compile time either a) when an
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7721 operation like memcpy will either overflow a buffer that corresponds to
7722 an object, or b) to determine that a runtime check for overflow isn't
7723 necessary. An object in this context means an allocation of a
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7724 specific class, structure, array, or other object.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7725
7726<h5>Arguments:</h5>
7727<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7728 argument is a pointer to or into the <tt>object</tt>. The second argument
7729 is a boolean 0 or 1. This argument determines whether you want the
7730 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7731 1, variables are not allowed.</p>
7732
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7733<h5>Semantics:</h5>
7734<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7735 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7736 (depending on the <tt>type</tt> argument if the size cannot be determined
7737 at compile time.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7738
7739</div>
7740
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7741<!-- *********************************************************************** -->
7742<hr>
7743<address>
7744 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7745 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7746 <a href="http://validator.w3.org/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7748
7749 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7750 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7751 Last modified: $Date$
7752</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7753
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7754</body>
7755</html>