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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / ced0daf95511dd017b6193a11e4f292afeeaba80 / . / 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.">
10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
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
373<div class="doc_code">
374<pre>
375%x = <a href="#i_add">add</a> i32 1, %x
376</pre>
377</div>
378
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]379<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
380 LLVM infrastructure provides a verification pass that may be used to verify
381 that an LLVM module is well formed. This pass is automatically run by the
382 parser after parsing input assembly and by the optimizer before it outputs
383 bitcode. The violations pointed out by the verifier pass indicate bugs in
384 transformation passes or input to the parser.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]385
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]386</div>
387
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]388<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]389
390<!-- *********************************************************************** -->
391<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
392<!-- *********************************************************************** -->
393
394<div class="doc_text">
395
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]396<p>LLVM identifiers come in two basic types: global and local. Global
397 identifiers (functions, global variables) begin with the <tt>'@'</tt>
398 character. Local identifiers (register names, types) begin with
399 the <tt>'%'</tt> character. Additionally, there are three different formats
400 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]401
402<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]403 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]404 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
405 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
406 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
407 other characters in their names can be surrounded with quotes. Special
408 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
409 ASCII code for the character in hexadecimal. In this way, any character
410 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]411
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]412 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]413 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]414
415 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]416 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]417</ol>
418
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]419<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]420 don't need to worry about name clashes with reserved words, and the set of
421 reserved words may be expanded in the future without penalty. Additionally,
422 unnamed identifiers allow a compiler to quickly come up with a temporary
423 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]424
425<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]426 languages. There are keywords for different opcodes
427 ('<tt><a href="#i_add">add</a></tt>',
428 '<tt><a href="#i_bitcast">bitcast</a></tt>',
429 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
430 ('<tt><a href="#t_void">void</a></tt>',
431 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
432 reserved words cannot conflict with variable names, because none of them
433 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]434
435<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]436 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]437
438<p>The easy way:</p>
439
440<div class="doc_code">
441<pre>
442%result = <a href="#i_mul">mul</a> i32 %X, 8
443</pre>
444</div>
445
446<p>After strength reduction:</p>
447
448<div class="doc_code">
449<pre>
450%result = <a href="#i_shl">shl</a> i32 %X, i8 3
451</pre>
452</div>
453
454<p>And the hard way:</p>
455
456<div class="doc_code">
457<pre>
Gabor Greifc0ea7672009-10-28 13:05:07 +0000[diff] [blame]458%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
459%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]460%result = <a href="#i_add">add</a> i32 %1, %1
461</pre>
462</div>
463
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]464<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
465 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]466
467<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]468 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]469 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]470
471 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]472 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]473
474 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]475</ol>
476
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]477<p>It also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]478 demonstrating instructions, we will follow an instruction with a comment that
479 defines the type and name of value produced. Comments are shown in italic
480 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]481
482</div>
483
484<!-- *********************************************************************** -->
485<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
486<!-- *********************************************************************** -->
487
488<!-- ======================================================================= -->
489<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
490</div>
491
492<div class="doc_text">
493
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]494<p>LLVM programs are composed of "Module"s, each of which is a translation unit
495 of the input programs. Each module consists of functions, global variables,
496 and symbol table entries. Modules may be combined together with the LLVM
497 linker, which merges function (and global variable) definitions, resolves
498 forward declarations, and merges symbol table entries. Here is an example of
499 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]500
501<div class="doc_code">
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]502<pre>
503<i>; Declare the string constant as a global constant.</i>
504<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]505
506<i>; External declaration of the puts function</i>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]507<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]508
509<i>; Definition of main function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]510define i32 @main() { <i>; i32()* </i>
511 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]512 %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]513
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]514 <i>; Call puts function to write out the string to stdout.</i>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]515 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]516 <a href="#i_ret">ret</a> i32 0<br>}
517
518<i>; Named metadata</i>
519!1 = metadata !{i32 41}
520!foo = !{!1, null}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]521</pre>
522</div>
523
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]524<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]525 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]526 a <a href="#functionstructure">function definition</a> for
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]527 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
528 "<tt>foo"</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]529
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]530<p>In general, a module is made up of a list of global values, where both
531 functions and global variables are global values. Global values are
532 represented by a pointer to a memory location (in this case, a pointer to an
533 array of char, and a pointer to a function), and have one of the
534 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]535
536</div>
537
538<!-- ======================================================================= -->
539<div class="doc_subsection">
540 <a name="linkage">Linkage Types</a>
541</div>
542
543<div class="doc_text">
544
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]545<p>All Global Variables and Functions have one of the following types of
546 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]547
548<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingf8239662010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
551 by objects in the current module. In particular, linking code into a
552 module with an private global value may cause the private to be renamed as
553 necessary to avoid collisions. Because the symbol is private to the
554 module, all references can be updated. This doesn't show up in any symbol
555 table in the object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]556
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]557 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendlingf8239662010-07-01 21:55:59 +0000[diff] [blame]558 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
559 assembler and evaluated by the linker. Unlike normal strong symbols, they
560 are removed by the linker from the final linked image (executable or
561 dynamic library).</dd>
562
563 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
564 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
565 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
566 linker. The symbols are removed by the linker from the final linked image
567 (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]568
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]569 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlinge066d262010-06-29 22:34:52 +0000[diff] [blame]570 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]571 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
572 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]573
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]574 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]575 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]576 into the object file corresponding to the LLVM module. They exist to
577 allow inlining and other optimizations to take place given knowledge of
578 the definition of the global, which is known to be somewhere outside the
579 module. Globals with <tt>available_externally</tt> linkage are allowed to
580 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
581 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]582
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]583 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]584 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattnerd16c5512010-01-09 19:15:14 +0000[diff] [blame]585 the same name when linkage occurs. This can be used to implement
586 some forms of inline functions, templates, or other code which must be
587 generated in each translation unit that uses it, but where the body may
588 be overridden with a more definitive definition later. Unreferenced
589 <tt>linkonce</tt> globals are allowed to be discarded. Note that
590 <tt>linkonce</tt> linkage does not actually allow the optimizer to
591 inline the body of this function into callers because it doesn't know if
592 this definition of the function is the definitive definition within the
593 program or whether it will be overridden by a stronger definition.
594 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
595 linkage.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]596
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]597 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]598 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
599 <tt>linkonce</tt> linkage, except that unreferenced globals with
600 <tt>weak</tt> linkage may not be discarded. This is used for globals that
601 are declared "weak" in C source code.</dd>
602
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]603 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]604 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
605 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
606 global scope.
607 Symbols with "<tt>common</tt>" linkage are merged in the same way as
608 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]609 <tt>common</tt> symbols may not have an explicit section,
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]610 must have a zero initializer, and may not be marked '<a
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]611 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
612 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]613
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]614
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]615 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]616 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]617 pointer to array type. When two global variables with appending linkage
618 are linked together, the two global arrays are appended together. This is
619 the LLVM, typesafe, equivalent of having the system linker append together
620 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]621
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]623 <dd>The semantics of this linkage follow the ELF object file model: the symbol
624 is weak until linked, if not linked, the symbol becomes null instead of
625 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]626
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]627 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
628 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]629 <dd>Some languages allow differing globals to be merged, such as two functions
630 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendlingf8239662010-07-01 21:55:59 +0000[diff] [blame]631 that only equivalent globals are ever merged (the "one definition rule"
632 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]633 and <tt>weak_odr</tt> linkage types to indicate that the global will only
634 be merged with equivalent globals. These linkage types are otherwise the
635 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]636
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]637 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]638 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]639 visible, meaning that it participates in linkage and can be used to
640 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]641</dl>
642
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]643<p>The next two types of linkage are targeted for Microsoft Windows platform
644 only. They are designed to support importing (exporting) symbols from (to)
645 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]646
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]647<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]648 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]649 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]650 or variable via a global pointer to a pointer that is set up by the DLL
651 exporting the symbol. On Microsoft Windows targets, the pointer name is
652 formed by combining <code>__imp_</code> and the function or variable
653 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]654
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]655 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]656 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]657 pointer to a pointer in a DLL, so that it can be referenced with the
658 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
659 name is formed by combining <code>__imp_</code> and the function or
660 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]661</dl>
662
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]663<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
664 another module defined a "<tt>.LC0</tt>" variable and was linked with this
665 one, one of the two would be renamed, preventing a collision. Since
666 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
667 declarations), they are accessible outside of the current module.</p>
668
669<p>It is illegal for a function <i>declaration</i> to have any linkage type
670 other than "externally visible", <tt>dllimport</tt>
671 or <tt>extern_weak</tt>.</p>
672
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]673<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]674 or <tt>weak_odr</tt> linkages.</p>
675
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]676</div>
677
678<!-- ======================================================================= -->
679<div class="doc_subsection">
680 <a name="callingconv">Calling Conventions</a>
681</div>
682
683<div class="doc_text">
684
685<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]686 and <a href="#i_invoke">invokes</a> can all have an optional calling
687 convention specified for the call. The calling convention of any pair of
688 dynamic caller/callee must match, or the behavior of the program is
689 undefined. The following calling conventions are supported by LLVM, and more
690 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]691
692<dl>
693 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]694 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]695 specified) matches the target C calling conventions. This calling
696 convention supports varargs function calls and tolerates some mismatch in
697 the declared prototype and implemented declaration of the function (as
698 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]699
700 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]701 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]702 (e.g. by passing things in registers). This calling convention allows the
703 target to use whatever tricks it wants to produce fast code for the
704 target, without having to conform to an externally specified ABI
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]705 (Application Binary Interface).
706 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnerac9a9392010-03-11 00:22:57 +0000[diff] [blame]707 when this or the GHC convention is used.</a> This calling convention
708 does not support varargs and requires the prototype of all callees to
709 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]710
711 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]712 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]713 as possible under the assumption that the call is not commonly executed.
714 As such, these calls often preserve all registers so that the call does
715 not break any live ranges in the caller side. This calling convention
716 does not support varargs and requires the prototype of all callees to
717 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]718
Chris Lattnerac9a9392010-03-11 00:22:57 +0000[diff] [blame]719 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
720 <dd>This calling convention has been implemented specifically for use by the
721 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
722 It passes everything in registers, going to extremes to achieve this by
723 disabling callee save registers. This calling convention should not be
724 used lightly but only for specific situations such as an alternative to
725 the <em>register pinning</em> performance technique often used when
726 implementing functional programming languages.At the moment only X86
727 supports this convention and it has the following limitations:
728 <ul>
729 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
730 floating point types are supported.</li>
731 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
732 6 floating point parameters.</li>
733 </ul>
734 This calling convention supports
735 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
736 requires both the caller and callee are using it.
737 </dd>
738
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]739 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]740 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]741 target-specific calling conventions to be used. Target specific calling
742 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]743</dl>
744
745<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]746 support Pascal conventions or any other well-known target-independent
747 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]748
749</div>
750
751<!-- ======================================================================= -->
752<div class="doc_subsection">
753 <a name="visibility">Visibility Styles</a>
754</div>
755
756<div class="doc_text">
757
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]758<p>All Global Variables and Functions have one of the following visibility
759 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]760
761<dl>
762 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]763 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]764 that the declaration is visible to other modules and, in shared libraries,
765 means that the declared entity may be overridden. On Darwin, default
766 visibility means that the declaration is visible to other modules. Default
767 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]768
769 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]770 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]771 object if they are in the same shared object. Usually, hidden visibility
772 indicates that the symbol will not be placed into the dynamic symbol
773 table, so no other module (executable or shared library) can reference it
774 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]775
776 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]777 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]778 the dynamic symbol table, but that references within the defining module
779 will bind to the local symbol. That is, the symbol cannot be overridden by
780 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]781</dl>
782
783</div>
784
785<!-- ======================================================================= -->
786<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]787 <a name="namedtypes">Named Types</a>
788</div>
789
790<div class="doc_text">
791
792<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]793 it easier to read the IR and make the IR more condensed (particularly when
794 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]795
796<div class="doc_code">
797<pre>
798%mytype = type { %mytype*, i32 }
799</pre>
800</div>
801
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]802<p>You may give a name to any <a href="#typesystem">type</a> except
803 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
804 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]805
806<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]807 and that you can therefore specify multiple names for the same type. This
808 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
809 uses structural typing, the name is not part of the type. When printing out
810 LLVM IR, the printer will pick <em>one name</em> to render all types of a
811 particular shape. This means that if you have code where two different
812 source types end up having the same LLVM type, that the dumper will sometimes
813 print the "wrong" or unexpected type. This is an important design point and
814 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]815
816</div>
817
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]818<!-- ======================================================================= -->
819<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]820 <a name="globalvars">Global Variables</a>
821</div>
822
823<div class="doc_text">
824
825<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]826 instead of run-time. Global variables may optionally be initialized, may
827 have an explicit section to be placed in, and may have an optional explicit
828 alignment specified. A variable may be defined as "thread_local", which
829 means that it will not be shared by threads (each thread will have a
830 separated copy of the variable). A variable may be defined as a global
831 "constant," which indicates that the contents of the variable
832 will <b>never</b> be modified (enabling better optimization, allowing the
833 global data to be placed in the read-only section of an executable, etc).
834 Note that variables that need runtime initialization cannot be marked
835 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]836
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]837<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
838 constant, even if the final definition of the global is not. This capability
839 can be used to enable slightly better optimization of the program, but
840 requires the language definition to guarantee that optimizations based on the
841 'constantness' are valid for the translation units that do not include the
842 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]843
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]844<p>As SSA values, global variables define pointer values that are in scope
845 (i.e. they dominate) all basic blocks in the program. Global variables
846 always define a pointer to their "content" type because they describe a
847 region of memory, and all memory objects in LLVM are accessed through
848 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]849
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]850<p>A global variable may be declared to reside in a target-specific numbered
851 address space. For targets that support them, address spaces may affect how
852 optimizations are performed and/or what target instructions are used to
853 access the variable. The default address space is zero. The address space
854 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]855
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]856<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]857 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]858
Chris Lattner72413b22010-04-28 00:13:42 +0000[diff] [blame]859<p>An explicit alignment may be specified for a global, which must be a power
860 of 2. If not present, or if the alignment is set to zero, the alignment of
861 the global is set by the target to whatever it feels convenient. If an
862 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner50d07d02010-04-28 00:31:12 +0000[diff] [blame]863 alignment. Targets and optimizers are not allowed to over-align the global
864 if the global has an assigned section. In this case, the extra alignment
865 could be observable: for example, code could assume that the globals are
866 densely packed in their section and try to iterate over them as an array,
867 alignment padding would break this iteration.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]868
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]869<p>For example, the following defines a global in a numbered address space with
870 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]871
872<div class="doc_code">
873<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]874@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]875</pre>
876</div>
877
878</div>
879
880
881<!-- ======================================================================= -->
882<div class="doc_subsection">
883 <a name="functionstructure">Functions</a>
884</div>
885
886<div class="doc_text">
887
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]888<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]889 optional <a href="#linkage">linkage type</a>, an optional
890 <a href="#visibility">visibility style</a>, an optional
891 <a href="#callingconv">calling convention</a>, a return type, an optional
892 <a href="#paramattrs">parameter attribute</a> for the return type, a function
893 name, a (possibly empty) argument list (each with optional
894 <a href="#paramattrs">parameter attributes</a>), optional
895 <a href="#fnattrs">function attributes</a>, an optional section, an optional
896 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
897 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]898
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]899<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
900 optional <a href="#linkage">linkage type</a>, an optional
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]901 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]902 <a href="#callingconv">calling convention</a>, a return type, an optional
903 <a href="#paramattrs">parameter attribute</a> for the return type, a function
904 name, a possibly empty list of arguments, an optional alignment, and an
905 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]906
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]907<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]908 (Control Flow Graph) for the function. Each basic block may optionally start
909 with a label (giving the basic block a symbol table entry), contains a list
910 of instructions, and ends with a <a href="#terminators">terminator</a>
911 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]912
913<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]914 executed on entrance to the function, and it is not allowed to have
915 predecessor basic blocks (i.e. there can not be any branches to the entry
916 block of a function). Because the block can have no predecessors, it also
917 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]918
919<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]920 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]921
922<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]923 the alignment is set to zero, the alignment of the function is set by the
924 target to whatever it feels convenient. If an explicit alignment is
925 specified, the function is forced to have at least that much alignment. All
926 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]927
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]928<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]929<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]930<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]931define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]932 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
933 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
934 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
935 [<a href="#gc">gc</a>] { ... }
936</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]937</div>
938
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]939</div>
940
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]941<!-- ======================================================================= -->
942<div class="doc_subsection">
943 <a name="aliasstructure">Aliases</a>
944</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]945
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]946<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]947
948<p>Aliases act as "second name" for the aliasee value (which can be either
949 function, global variable, another alias or bitcast of global value). Aliases
950 may have an optional <a href="#linkage">linkage type</a>, and an
951 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]952
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]953<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]954<div class="doc_code">
955<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]956@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]957</pre>
958</div>
959
960</div>
961
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]962<!-- ======================================================================= -->
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]963<div class="doc_subsection">
964 <a name="namedmetadatastructure">Named Metadata</a>
965</div>
966
967<div class="doc_text">
968
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]969<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
970 nodes</a> (but not metadata strings) and null are the only valid operands for
971 a named metadata.</p>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]972
973<h5>Syntax:</h5>
974<div class="doc_code">
975<pre>
976!1 = metadata !{metadata !"one"}
977!name = !{null, !1}
978</pre>
979</div>
980
981</div>
982
983<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]984<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]985
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]986<div class="doc_text">
987
988<p>The return type and each parameter of a function type may have a set of
989 <i>parameter attributes</i> associated with them. Parameter attributes are
990 used to communicate additional information about the result or parameters of
991 a function. Parameter attributes are considered to be part of the function,
992 not of the function type, so functions with different parameter attributes
993 can have the same function type.</p>
994
995<p>Parameter attributes are simple keywords that follow the type specified. If
996 multiple parameter attributes are needed, they are space separated. For
997 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]998
999<div class="doc_code">
1000<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]1001declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]1002declare i32 @atoi(i8 zeroext)
1003declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1004</pre>
1005</div>
1006
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1007<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1008 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1009
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1010<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1011
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1012<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1013 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1014 <dd>This indicates to the code generator that the parameter or return value
1015 should be zero-extended to a 32-bit value by the caller (for a parameter)
1016 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1017
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1018 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1019 <dd>This indicates to the code generator that the parameter or return value
1020 should be sign-extended to a 32-bit value by the caller (for a parameter)
1021 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1022
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1023 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1024 <dd>This indicates that this parameter or return value should be treated in a
1025 special target-dependent fashion during while emitting code for a function
1026 call or return (usually, by putting it in a register as opposed to memory,
1027 though some targets use it to distinguish between two different kinds of
1028 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1029
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1030 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1031 <dd>This indicates that the pointer parameter should really be passed by value
1032 to the function. The attribute implies that a hidden copy of the pointee
1033 is made between the caller and the callee, so the callee is unable to
1034 modify the value in the callee. This attribute is only valid on LLVM
1035 pointer arguments. It is generally used to pass structs and arrays by
1036 value, but is also valid on pointers to scalars. The copy is considered
1037 to belong to the caller not the callee (for example,
1038 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1039 <tt>byval</tt> parameters). This is not a valid attribute for return
1040 values. The byval attribute also supports specifying an alignment with
1041 the align attribute. This has a target-specific effect on the code
1042 generator that usually indicates a desired alignment for the synthesized
1043 stack slot.</dd>
1044
Dan Gohmanbd2f9ba2010-07-02 23:18:08 +0000[diff] [blame]1045 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1046 <dd>This indicates that the pointer parameter specifies the address of a
1047 structure that is the return value of the function in the source program.
1048 This pointer must be guaranteed by the caller to be valid: loads and
1049 stores to the structure may be assumed by the callee to not to trap. This
1050 may only be applied to the first parameter. This is not a valid attribute
1051 for return values. </dd>
1052
Dan Gohmanbd2f9ba2010-07-02 23:18:08 +0000[diff] [blame]1053 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmanc8208442010-07-02 18:41:32 +0000[diff] [blame]1054 <dd>This indicates that pointer values
1055 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohman24fc36d2010-07-02 23:46:54 +0000[diff] [blame]1056 value do not alias pointer values which are not <i>based</i> on it,
1057 ignoring certain "irrelevant" dependencies.
1058 For a call to the parent function, dependencies between memory
1059 references from before or after the call and from those during the call
1060 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1061 return value used in that call.
Dan Gohmanc8208442010-07-02 18:41:32 +0000[diff] [blame]1062 The caller shares the responsibility with the callee for ensuring that
1063 these requirements are met.
1064 For further details, please see the discussion of the NoAlias response in
Dan Gohman8c6704c2010-07-06 15:26:33 +0000[diff] [blame]1065 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1066<br>
John McCall0f56d702010-07-06 21:07:14 +0000[diff] [blame]1067 Note that this definition of <tt>noalias</tt> is intentionally
1068 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattnerd6c58d82010-07-06 20:51:35 +0000[diff] [blame]1069 arguments, though it is slightly weaker.
Dan Gohman8c6704c2010-07-06 15:26:33 +0000[diff] [blame]1070<br>
1071 For function return values, C99's <tt>restrict</tt> is not meaningful,
1072 while LLVM's <tt>noalias</tt> is.
1073 </dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1074
Dan Gohmanbd2f9ba2010-07-02 23:18:08 +0000[diff] [blame]1075 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1076 <dd>This indicates that the callee does not make any copies of the pointer
1077 that outlive the callee itself. This is not a valid attribute for return
1078 values.</dd>
1079
Dan Gohmanbd2f9ba2010-07-02 23:18:08 +0000[diff] [blame]1080 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1081 <dd>This indicates that the pointer parameter can be excised using the
1082 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1083 attribute for return values.</dd>
1084</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1085
1086</div>
1087
1088<!-- ======================================================================= -->
1089<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1090 <a name="gc">Garbage Collector Names</a>
1091</div>
1092
1093<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1094
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1095<p>Each function may specify a garbage collector name, which is simply a
1096 string:</p>
1097
1098<div class="doc_code">
1099<pre>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1100define void @f() gc "name" { ... }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1101</pre>
1102</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1103
1104<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1105 collector which will cause the compiler to alter its output in order to
1106 support the named garbage collection algorithm.</p>
1107
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1108</div>
1109
1110<!-- ======================================================================= -->
1111<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1112 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1113</div>
1114
1115<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1116
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1117<p>Function attributes are set to communicate additional information about a
1118 function. Function attributes are considered to be part of the function, not
1119 of the function type, so functions with different parameter attributes can
1120 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1121
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1122<p>Function attributes are simple keywords that follow the type specified. If
1123 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1124
1125<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1126<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1127define void @f() noinline { ... }
1128define void @f() alwaysinline { ... }
1129define void @f() alwaysinline optsize { ... }
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1130define void @f() optsize { ... }
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1131</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1132</div>
1133
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1134<dl>
Charles Davisfaa8f752010-02-12 00:31:15 +0000[diff] [blame]1135 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1136 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1137 the backend should forcibly align the stack pointer. Specify the
1138 desired alignment, which must be a power of two, in parentheses.
1139
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1140 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1141 <dd>This attribute indicates that the inliner should attempt to inline this
1142 function into callers whenever possible, ignoring any active inlining size
1143 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1144
Jakob Stoklund Olesen77180732010-02-06 01:16:28 +0000[diff] [blame]1145 <dt><tt><b>inlinehint</b></tt></dt>
1146 <dd>This attribute indicates that the source code contained a hint that inlining
1147 this function is desirable (such as the "inline" keyword in C/C++). It
1148 is just a hint; it imposes no requirements on the inliner.</dd>
1149
Nick Lewyckybc036ee2010-07-06 18:24:09 +0000[diff] [blame]1150 <dt><tt><b>naked</b></tt></dt>
1151 <dd>This attribute disables prologue / epilogue emission for the function.
1152 This can have very system-specific consequences.</dd>
1153
1154 <dt><tt><b>noimplicitfloat</b></tt></dt>
1155 <dd>This attributes disables implicit floating point instructions.</dd>
1156
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1157 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1158 <dd>This attribute indicates that the inliner should never inline this
1159 function in any situation. This attribute may not be used together with
1160 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1161
Nick Lewyckybc036ee2010-07-06 18:24:09 +0000[diff] [blame]1162 <dt><tt><b>noredzone</b></tt></dt>
1163 <dd>This attribute indicates that the code generator should not use a red
1164 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1165
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1166 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1167 <dd>This function attribute indicates that the function never returns
1168 normally. This produces undefined behavior at runtime if the function
1169 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1170
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1171 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1172 <dd>This function attribute indicates that the function never returns with an
1173 unwind or exceptional control flow. If the function does unwind, its
1174 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1175
Nick Lewyckybc036ee2010-07-06 18:24:09 +0000[diff] [blame]1176 <dt><tt><b>optsize</b></tt></dt>
1177 <dd>This attribute suggests that optimization passes and code generator passes
1178 make choices that keep the code size of this function low, and otherwise
1179 do optimizations specifically to reduce code size.</dd>
1180
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1181 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1182 <dd>This attribute indicates that the function computes its result (or decides
1183 to unwind an exception) based strictly on its arguments, without
1184 dereferencing any pointer arguments or otherwise accessing any mutable
1185 state (e.g. memory, control registers, etc) visible to caller functions.
1186 It does not write through any pointer arguments
1187 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1188 changes any state visible to callers. This means that it cannot unwind
1189 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1190 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1191
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1192 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1193 <dd>This attribute indicates that the function does not write through any
1194 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1195 arguments) or otherwise modify any state (e.g. memory, control registers,
1196 etc) visible to caller functions. It may dereference pointer arguments
1197 and read state that may be set in the caller. A readonly function always
1198 returns the same value (or unwinds an exception identically) when called
1199 with the same set of arguments and global state. It cannot unwind an
1200 exception by calling the <tt>C++</tt> exception throwing methods, but may
1201 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1202
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1203 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1204 <dd>This attribute indicates that the function should emit a stack smashing
1205 protector. It is in the form of a "canary"&mdash;a random value placed on
1206 the stack before the local variables that's checked upon return from the
1207 function to see if it has been overwritten. A heuristic is used to
1208 determine if a function needs stack protectors or not.<br>
1209<br>
1210 If a function that has an <tt>ssp</tt> attribute is inlined into a
1211 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1212 function will have an <tt>ssp</tt> attribute.</dd>
1213
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1214 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1215 <dd>This attribute indicates that the function should <em>always</em> emit a
1216 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1217 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1218<br>
1219 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1220 function that doesn't have an <tt>sspreq</tt> attribute or which has
1221 an <tt>ssp</tt> attribute, then the resulting function will have
1222 an <tt>sspreq</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1223</dl>
1224
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1225</div>
1226
1227<!-- ======================================================================= -->
1228<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1229 <a name="moduleasm">Module-Level Inline Assembly</a>
1230</div>
1231
1232<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1233
1234<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1235 the GCC "file scope inline asm" blocks. These blocks are internally
1236 concatenated by LLVM and treated as a single unit, but may be separated in
1237 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1238
1239<div class="doc_code">
1240<pre>
1241module asm "inline asm code goes here"
1242module asm "more can go here"
1243</pre>
1244</div>
1245
1246<p>The strings can contain any character by escaping non-printable characters.
1247 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]1248 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1249
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1250<p>The inline asm code is simply printed to the machine code .s file when
1251 assembly code is generated.</p>
1252
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1253</div>
1254
1255<!-- ======================================================================= -->
1256<div class="doc_subsection">
1257 <a name="datalayout">Data Layout</a>
1258</div>
1259
1260<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1261
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1262<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1263 data is to be laid out in memory. The syntax for the data layout is
1264 simply:</p>
1265
1266<div class="doc_code">
1267<pre>
1268target datalayout = "<i>layout specification</i>"
1269</pre>
1270</div>
1271
1272<p>The <i>layout specification</i> consists of a list of specifications
1273 separated by the minus sign character ('-'). Each specification starts with
1274 a letter and may include other information after the letter to define some
1275 aspect of the data layout. The specifications accepted are as follows:</p>
1276
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1277<dl>
1278 <dt><tt>E</tt></dt>
1279 <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]1280 bits with the most significance have the lowest address location.</dd>
1281
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1282 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1283 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1284 the bits with the least significance have the lowest address
1285 location.</dd>
1286
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1287 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1288 <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]1289 <i>preferred</i> alignments. All sizes are in bits. Specifying
1290 the <i>pref</i> alignment is optional. If omitted, the
1291 preceding <tt>:</tt> should be omitted too.</dd>
1292
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1293 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1294 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1295 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1296
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1297 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1298 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1299 <i>size</i>.</dd>
1300
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1301 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1302 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen7dabc4c2010-05-28 18:54:47 +0000[diff] [blame]1303 <i>size</i>. Only values of <i>size</i> that are supported by the target
1304 will work. 32 (float) and 64 (double) are supported on all targets;
1305 80 or 128 (different flavors of long double) are also supported on some
1306 targets.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1307
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1308 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1309 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1310 <i>size</i>.</dd>
1311
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1312 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1313 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1314 <i>size</i>.</dd>
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1315
1316 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1317 <dd>This specifies a set of native integer widths for the target CPU
1318 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1319 "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]1320 this set are considered to support most general arithmetic
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1321 operations efficiently.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1322</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1323
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1324<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohmanfde3cd72010-04-28 00:36:01 +0000[diff] [blame]1325 default set of specifications which are then (possibly) overridden by the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1326 specifications in the <tt>datalayout</tt> keyword. The default specifications
1327 are given in this list:</p>
1328
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1329<ul>
1330 <li><tt>E</tt> - big endian</li>
Dan Gohmane78194f2010-02-23 02:44:03 +0000[diff] [blame]1331 <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]1332 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1333 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1334 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1335 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1336 <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]1337 alignment of 64-bits</li>
1338 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1339 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1340 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1341 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1342 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1343 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1344</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1345
1346<p>When LLVM is determining the alignment for a given type, it uses the
1347 following rules:</p>
1348
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1349<ol>
1350 <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]1351 specification is used.</li>
1352
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1353 <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]1354 smallest integer type that is larger than the bitwidth of the sought type
1355 is used. If none of the specifications are larger than the bitwidth then
1356 the the largest integer type is used. For example, given the default
1357 specifications above, the i7 type will use the alignment of i8 (next
1358 largest) while both i65 and i256 will use the alignment of i64 (largest
1359 specified).</li>
1360
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1361 <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]1362 largest vector type that is smaller than the sought vector type will be
1363 used as a fall back. This happens because &lt;128 x double&gt; can be
1364 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1365</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1366
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1367</div>
1368
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1369<!-- ======================================================================= -->
1370<div class="doc_subsection">
1371 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1372</div>
1373
1374<div class="doc_text">
1375
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1376<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1377with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1378is undefined. Pointer values are associated with address ranges
1379according to the following rules:</p>
1380
1381<ul>
Dan Gohmanc8208442010-07-02 18:41:32 +0000[diff] [blame]1382 <li>A pointer value is associated with the addresses associated with
1383 any value it is <i>based</i> on.
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1384 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1385 range of the variable's storage.</li>
1386 <li>The result value of an allocation instruction is associated with
1387 the address range of the allocated storage.</li>
1388 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1389 no address.</li>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1390 <li>An integer constant other than zero or a pointer value returned
1391 from a function not defined within LLVM may be associated with address
1392 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1393 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1394 allocated by mechanisms provided by LLVM.</li>
Dan Gohmanc8208442010-07-02 18:41:32 +0000[diff] [blame]1395</ul>
1396
1397<p>A pointer value is <i>based</i> on another pointer value according
1398 to the following rules:</p>
1399
1400<ul>
1401 <li>A pointer value formed from a
1402 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1403 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1404 <li>The result value of a
1405 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1406 of the <tt>bitcast</tt>.</li>
1407 <li>A pointer value formed by an
1408 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1409 pointer values that contribute (directly or indirectly) to the
1410 computation of the pointer's value.</li>
1411 <li>The "<i>based</i> on" relationship is transitive.</li>
1412</ul>
1413
1414<p>Note that this definition of <i>"based"</i> is intentionally
1415 similar to the definition of <i>"based"</i> in C99, though it is
1416 slightly weaker.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1417
1418<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1419<tt><a href="#i_load">load</a></tt> merely indicates the size and
1420alignment of the memory from which to load, as well as the
Dan Gohmand72730e2010-06-17 19:23:50 +0000[diff] [blame]1421interpretation of the value. The first operand type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1422<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1423and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1424
1425<p>Consequently, type-based alias analysis, aka TBAA, aka
1426<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1427LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1428additional information which specialized optimization passes may use
1429to implement type-based alias analysis.</p>
1430
1431</div>
1432
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]1433<!-- ======================================================================= -->
1434<div class="doc_subsection">
1435 <a name="volatile">Volatile Memory Accesses</a>
1436</div>
1437
1438<div class="doc_text">
1439
1440<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1441href="#i_store"><tt>store</tt></a>s, and <a
1442href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1443The optimizers must not change the number of volatile operations or change their
1444order of execution relative to other volatile operations. The optimizers
1445<i>may</i> change the order of volatile operations relative to non-volatile
1446operations. This is not Java's "volatile" and has no cross-thread
1447synchronization behavior.</p>
1448
1449</div>
1450
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1451<!-- *********************************************************************** -->
1452<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1453<!-- *********************************************************************** -->
1454
1455<div class="doc_text">
1456
1457<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1458 intermediate representation. Being typed enables a number of optimizations
1459 to be performed on the intermediate representation directly, without having
1460 to do extra analyses on the side before the transformation. A strong type
1461 system makes it easier to read the generated code and enables novel analyses
1462 and transformations that are not feasible to perform on normal three address
1463 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1464
1465</div>
1466
1467<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1468<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1469Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1470
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1471<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1472
1473<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1474
1475<table border="1" cellspacing="0" cellpadding="4">
1476 <tbody>
1477 <tr><th>Classification</th><th>Types</th></tr>
1478 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1479 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1480 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1481 </tr>
1482 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1483 <td><a href="#t_floating">floating point</a></td>
1484 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1485 </tr>
1486 <tr>
1487 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1488 <td><a href="#t_integer">integer</a>,
1489 <a href="#t_floating">floating point</a>,
1490 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1491 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1492 <a href="#t_struct">structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1493 <a href="#t_union">union</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1494 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1495 <a href="#t_label">label</a>,
1496 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1497 </td>
1498 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1499 <tr>
1500 <td><a href="#t_primitive">primitive</a></td>
1501 <td><a href="#t_label">label</a>,
1502 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1503 <a href="#t_floating">floating point</a>,
1504 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1505 </tr>
1506 <tr>
1507 <td><a href="#t_derived">derived</a></td>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1508 <td><a href="#t_array">array</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1509 <a href="#t_function">function</a>,
1510 <a href="#t_pointer">pointer</a>,
1511 <a href="#t_struct">structure</a>,
1512 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1513 <a href="#t_union">union</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1514 <a href="#t_vector">vector</a>,
1515 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1516 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1517 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1518 </tbody>
1519</table>
1520
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1521<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1522 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1523 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1524
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1525</div>
1526
1527<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1528<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1529
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1530<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1531
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1532<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1533 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1534
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1535</div>
1536
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1537<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1538<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1539
1540<div class="doc_text">
1541
1542<h5>Overview:</h5>
1543<p>The integer type is a very simple type that simply specifies an arbitrary
1544 bit width for the integer type desired. Any bit width from 1 bit to
1545 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1546
1547<h5>Syntax:</h5>
1548<pre>
1549 iN
1550</pre>
1551
1552<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1553 value.</p>
1554
1555<h5>Examples:</h5>
1556<table class="layout">
1557 <tr class="layout">
1558 <td class="left"><tt>i1</tt></td>
1559 <td class="left">a single-bit integer.</td>
1560 </tr>
1561 <tr class="layout">
1562 <td class="left"><tt>i32</tt></td>
1563 <td class="left">a 32-bit integer.</td>
1564 </tr>
1565 <tr class="layout">
1566 <td class="left"><tt>i1942652</tt></td>
1567 <td class="left">a really big integer of over 1 million bits.</td>
1568 </tr>
1569</table>
1570
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1571</div>
1572
1573<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1574<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1575
1576<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1577
1578<table>
1579 <tbody>
1580 <tr><th>Type</th><th>Description</th></tr>
1581 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1582 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1583 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1584 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1585 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1586 </tbody>
1587</table>
1588
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1589</div>
1590
1591<!-- _______________________________________________________________________ -->
1592<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1593
1594<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1595
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1596<h5>Overview:</h5>
1597<p>The void type does not represent any value and has no size.</p>
1598
1599<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1600<pre>
1601 void
1602</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1603
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1604</div>
1605
1606<!-- _______________________________________________________________________ -->
1607<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1608
1609<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1610
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1611<h5>Overview:</h5>
1612<p>The label type represents code labels.</p>
1613
1614<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1615<pre>
1616 label
1617</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1618
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1619</div>
1620
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1621<!-- _______________________________________________________________________ -->
1622<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1623
1624<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1625
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1626<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1627<p>The metadata type represents embedded metadata. No derived types may be
1628 created from metadata except for <a href="#t_function">function</a>
1629 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1630
1631<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1632<pre>
1633 metadata
1634</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1635
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1636</div>
1637
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1638
1639<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1640<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1641
1642<div class="doc_text">
1643
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1644<p>The real power in LLVM comes from the derived types in the system. This is
1645 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1646 useful types. Each of these types contain one or more element types which
1647 may be a primitive type, or another derived type. For example, it is
1648 possible to have a two dimensional array, using an array as the element type
1649 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1650
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1651
1652</div>
1653
1654<!-- _______________________________________________________________________ -->
1655<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1656
1657<div class="doc_text">
1658
1659<p>Aggregate Types are a subset of derived types that can contain multiple
1660 member types. <a href="#t_array">Arrays</a>,
1661 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1662 <a href="#t_union">unions</a> are aggregate types.</p>
1663
1664</div>
1665
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1666</div>
1667
1668<!-- _______________________________________________________________________ -->
1669<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1670
1671<div class="doc_text">
1672
1673<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1674<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1675 sequentially in memory. The array type requires a size (number of elements)
1676 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1677
1678<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1679<pre>
1680 [&lt;# elements&gt; x &lt;elementtype&gt;]
1681</pre>
1682
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1683<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1684 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1685
1686<h5>Examples:</h5>
1687<table class="layout">
1688 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1689 <td class="left"><tt>[40 x i32]</tt></td>
1690 <td class="left">Array of 40 32-bit integer values.</td>
1691 </tr>
1692 <tr class="layout">
1693 <td class="left"><tt>[41 x i32]</tt></td>
1694 <td class="left">Array of 41 32-bit integer values.</td>
1695 </tr>
1696 <tr class="layout">
1697 <td class="left"><tt>[4 x i8]</tt></td>
1698 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1699 </tr>
1700</table>
1701<p>Here are some examples of multidimensional arrays:</p>
1702<table class="layout">
1703 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1704 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1705 <td class="left">3x4 array of 32-bit integer values.</td>
1706 </tr>
1707 <tr class="layout">
1708 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1709 <td class="left">12x10 array of single precision floating point values.</td>
1710 </tr>
1711 <tr class="layout">
1712 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1713 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1714 </tr>
1715</table>
1716
Dan Gohman87ec5ad2009-11-09 19:01:53 +0000[diff] [blame]1717<p>There is no restriction on indexing beyond the end of the array implied by
1718 a static type (though there are restrictions on indexing beyond the bounds
1719 of an allocated object in some cases). This means that single-dimension
1720 'variable sized array' addressing can be implemented in LLVM with a zero
1721 length array type. An implementation of 'pascal style arrays' in LLVM could
1722 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1723
1724</div>
1725
1726<!-- _______________________________________________________________________ -->
1727<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1728
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1729<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1730
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1731<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1732<p>The function type can be thought of as a function signature. It consists of
1733 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]1734 function type is a scalar type, a void type, a struct type, or a union
1735 type. If the return type is a struct type then all struct elements must be
1736 of first class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1737
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1738<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1739<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1740 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1741</pre>
1742
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1743<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]1744 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1745 which indicates that the function takes a variable number of arguments.
1746 Variable argument functions can access their arguments with
1747 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1748 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1749 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1750
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1751<h5>Examples:</h5>
1752<table class="layout">
1753 <tr class="layout">
1754 <td class="left"><tt>i32 (i32)</tt></td>
1755 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1756 </td>
1757 </tr><tr class="layout">
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1758 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1759 </tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1760 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1761 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1762 returning <tt>float</tt>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1763 </td>
1764 </tr><tr class="layout">
1765 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1766 <td class="left">A vararg function that takes at least one
1767 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1768 which returns an integer. This is the signature for <tt>printf</tt> in
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1769 LLVM.
1770 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1771 </tr><tr class="layout">
1772 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1773 <td class="left">A function taking an <tt>i32</tt>, returning a
1774 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1775 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1776 </tr>
1777</table>
1778
1779</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1780
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1781<!-- _______________________________________________________________________ -->
1782<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1783
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1784<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1785
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1786<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1787<p>The structure type is used to represent a collection of data members together
1788 in memory. The packing of the field types is defined to match the ABI of the
1789 underlying processor. The elements of a structure may be any type that has a
1790 size.</p>
1791
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]1792<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1793 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1794 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1795 Structures in registers are accessed using the
1796 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1797 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1798<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1799<pre>
1800 { &lt;type list&gt; }
1801</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1803<h5>Examples:</h5>
1804<table class="layout">
1805 <tr class="layout">
1806 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1807 <td class="left">A triple of three <tt>i32</tt> values</td>
1808 </tr><tr class="layout">
1809 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1810 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1811 second element is a <a href="#t_pointer">pointer</a> to a
1812 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1813 an <tt>i32</tt>.</td>
1814 </tr>
1815</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1816
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1817</div>
1818
1819<!-- _______________________________________________________________________ -->
1820<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1821</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1822
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1823<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1824
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1825<h5>Overview:</h5>
1826<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1827 together in memory. There is no padding between fields. Further, the
1828 alignment of a packed structure is 1 byte. The elements of a packed
1829 structure may be any type that has a size.</p>
1830
1831<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1832 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1833 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1834
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1835<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1836<pre>
1837 &lt; { &lt;type list&gt; } &gt;
1838</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1839
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1840<h5>Examples:</h5>
1841<table class="layout">
1842 <tr class="layout">
1843 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1844 <td class="left">A triple of three <tt>i32</tt> values</td>
1845 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1846 <td class="left">
1847<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1848 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1849 second element is a <a href="#t_pointer">pointer</a> to a
1850 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1851 an <tt>i32</tt>.</td>
1852 </tr>
1853</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1854
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1855</div>
1856
1857<!-- _______________________________________________________________________ -->
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1858<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1859
1860<div class="doc_text">
1861
1862<h5>Overview:</h5>
1863<p>A union type describes an object with size and alignment suitable for
1864 an object of any one of a given set of types (also known as an "untagged"
1865 union). It is similar in concept and usage to a
1866 <a href="#t_struct">struct</a>, except that all members of the union
1867 have an offset of zero. The elements of a union may be any type that has a
1868 size. Unions must have at least one member - empty unions are not allowed.
1869 </p>
1870
1871<p>The size of the union as a whole will be the size of its largest member,
1872 and the alignment requirements of the union as a whole will be the largest
1873 alignment requirement of any member.</p>
1874
Dan Gohmanef8400c2010-02-25 16:51:31 +0000[diff] [blame]1875<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]1876 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1877 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1878 Since all members are at offset zero, the getelementptr instruction does
1879 not affect the address, only the type of the resulting pointer.</p>
1880
1881<h5>Syntax:</h5>
1882<pre>
1883 union { &lt;type list&gt; }
1884</pre>
1885
1886<h5>Examples:</h5>
1887<table class="layout">
1888 <tr class="layout">
1889 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1890 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1891 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1892 </tr><tr class="layout">
1893 <td class="left">
1894 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1895 <td class="left">A union, where the first element is a <tt>float</tt> and the
1896 second element is a <a href="#t_pointer">pointer</a> to a
1897 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1898 an <tt>i32</tt>.</td>
1899 </tr>
1900</table>
1901
1902</div>
1903
1904<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1905<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1906
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1907<div class="doc_text">
1908
1909<h5>Overview:</h5>
Dan Gohmanb2f72c82010-02-25 16:50:07 +0000[diff] [blame]1910<p>The pointer type is used to specify memory locations.
1911 Pointers are commonly used to reference objects in memory.</p>
1912
1913<p>Pointer types may have an optional address space attribute defining the
1914 numbered address space where the pointed-to object resides. The default
1915 address space is number zero. The semantics of non-zero address
1916 spaces are target-specific.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1917
1918<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1919 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1920
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1921<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1922<pre>
1923 &lt;type&gt; *
1924</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1925
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1926<h5>Examples:</h5>
1927<table class="layout">
1928 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1929 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1930 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1931 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1932 </tr>
1933 <tr class="layout">
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]1934 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1935 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1936 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1937 <tt>i32</tt>.</td>
1938 </tr>
1939 <tr class="layout">
1940 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1941 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1942 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1943 </tr>
1944</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1945
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1946</div>
1947
1948<!-- _______________________________________________________________________ -->
1949<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1950
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1951<div class="doc_text">
1952
1953<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1954<p>A vector type is a simple derived type that represents a vector of elements.
1955 Vector types are used when multiple primitive data are operated in parallel
1956 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands87598b02009-11-27 13:38:03 +0000[diff] [blame]1957 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1958 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1959
1960<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1961<pre>
1962 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1963</pre>
1964
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1965<p>The number of elements is a constant integer value; elementtype may be any
1966 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1967
1968<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1969<table class="layout">
1970 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1971 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1972 <td class="left">Vector of 4 32-bit integer values.</td>
1973 </tr>
1974 <tr class="layout">
1975 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1976 <td class="left">Vector of 8 32-bit floating-point values.</td>
1977 </tr>
1978 <tr class="layout">
1979 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1980 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1981 </tr>
1982</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1983
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1984</div>
1985
1986<!-- _______________________________________________________________________ -->
1987<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1988<div class="doc_text">
1989
1990<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1991<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1992 corresponds (for example) to the C notion of a forward declared structure
1993 type. In LLVM, opaque types can eventually be resolved to any type (not just
1994 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1995
1996<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1997<pre>
1998 opaque
1999</pre>
2000
2001<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2002<table class="layout">
2003 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]2004 <td class="left"><tt>opaque</tt></td>
2005 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2006 </tr>
2007</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2008
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2009</div>
2010
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2011<!-- ======================================================================= -->
2012<div class="doc_subsection">
2013 <a name="t_uprefs">Type Up-references</a>
2014</div>
2015
2016<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2017
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2018<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2019<p>An "up reference" allows you to refer to a lexically enclosing type without
2020 requiring it to have a name. For instance, a structure declaration may
2021 contain a pointer to any of the types it is lexically a member of. Example
2022 of up references (with their equivalent as named type declarations)
2023 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2024
2025<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]2026 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2027 { \2 }* %y = type { %y }*
2028 \1* %z = type %z*
2029</pre>
2030
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2031<p>An up reference is needed by the asmprinter for printing out cyclic types
2032 when there is no declared name for a type in the cycle. Because the
2033 asmprinter does not want to print out an infinite type string, it needs a
2034 syntax to handle recursive types that have no names (all names are optional
2035 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2036
2037<h5>Syntax:</h5>
2038<pre>
2039 \&lt;level&gt;
2040</pre>
2041
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2042<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]2043
2044<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2045<table class="layout">
2046 <tr class="layout">
2047 <td class="left"><tt>\1*</tt></td>
2048 <td class="left">Self-referential pointer.</td>
2049 </tr>
2050 <tr class="layout">
2051 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2052 <td class="left">Recursive structure where the upref refers to the out-most
2053 structure.</td>
2054 </tr>
2055</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2056
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2057</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2058
2059<!-- *********************************************************************** -->
2060<div class="doc_section"> <a name="constants">Constants</a> </div>
2061<!-- *********************************************************************** -->
2062
2063<div class="doc_text">
2064
2065<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2066 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2067
2068</div>
2069
2070<!-- ======================================================================= -->
2071<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
2072
2073<div class="doc_text">
2074
2075<dl>
2076 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2077 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]2078 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2079
2080 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2081 <dd>Standard integers (such as '4') are constants of
2082 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2083 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2084
2085 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2086 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2087 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2088 notation (see below). The assembler requires the exact decimal value of a
2089 floating-point constant. For example, the assembler accepts 1.25 but
2090 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2091 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2092
2093 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2094 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2095 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2096</dl>
2097
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2098<p>The one non-intuitive notation for constants is the hexadecimal form of
2099 floating point constants. For example, the form '<tt>double
2100 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2101 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2102 constants are required (and the only time that they are generated by the
2103 disassembler) is when a floating point constant must be emitted but it cannot
2104 be represented as a decimal floating point number in a reasonable number of
2105 digits. For example, NaN's, infinities, and other special values are
2106 represented in their IEEE hexadecimal format so that assembly and disassembly
2107 do not cause any bits to change in the constants.</p>
2108
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]2109<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2110 represented using the 16-digit form shown above (which matches the IEEE754
2111 representation for double); float values must, however, be exactly
2112 representable as IEE754 single precision. Hexadecimal format is always used
2113 for long double, and there are three forms of long double. The 80-bit format
2114 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2115 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2116 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2117 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2118 currently supported target uses this format. Long doubles will only work if
2119 they match the long double format on your target. All hexadecimal formats
2120 are big-endian (sign bit at the left).</p>
2121
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2122</div>
2123
2124<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2125<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2126<a name="aggregateconstants"></a> <!-- old anchor -->
2127<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2128</div>
2129
2130<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2131
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2132<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2133 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2134
2135<dl>
2136 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2137 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2138 type definitions (a comma separated list of elements, surrounded by braces
2139 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2140 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2141 Structure constants must have <a href="#t_struct">structure type</a>, and
2142 the number and types of elements must match those specified by the
2143 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2144
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2145 <dt><b>Union constants</b></dt>
2146 <dd>Union constants are represented with notation similar to a structure with
2147 a single element - that is, a single typed element surrounded
2148 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2149 <a href="#t_union">union type</a> can be initialized with a single-element
2150 struct as long as the type of the struct element matches the type of
2151 one of the union members.</dd>
2152
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2153 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2154 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2155 definitions (a comma separated list of elements, surrounded by square
2156 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2157 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2158 the number and types of elements must match those specified by the
2159 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2160
2161 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2162 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2163 definitions (a comma separated list of elements, surrounded by
2164 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2165 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2166 have <a href="#t_vector">vector type</a>, and the number and types of
2167 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2168
2169 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2170 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2171 value to zero of <em>any</em> type, including scalar and
2172 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2173 This is often used to avoid having to print large zero initializers
2174 (e.g. for large arrays) and is always exactly equivalent to using explicit
2175 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2176
2177 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]2178 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2179 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2180 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2181 be interpreted as part of the instruction stream, metadata is a place to
2182 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2183</dl>
2184
2185</div>
2186
2187<!-- ======================================================================= -->
2188<div class="doc_subsection">
2189 <a name="globalconstants">Global Variable and Function Addresses</a>
2190</div>
2191
2192<div class="doc_text">
2193
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2194<p>The addresses of <a href="#globalvars">global variables</a>
2195 and <a href="#functionstructure">functions</a> are always implicitly valid
2196 (link-time) constants. These constants are explicitly referenced when
2197 the <a href="#identifiers">identifier for the global</a> is used and always
2198 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2199 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2200
2201<div class="doc_code">
2202<pre>
2203@X = global i32 17
2204@Y = global i32 42
2205@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2206</pre>
2207</div>
2208
2209</div>
2210
2211<!-- ======================================================================= -->
2212<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2213<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2214
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2215<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]2216 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2217 Undefined values may be of any type (other than label or void) and be used
2218 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2219
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2220<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2221 program is well defined no matter what value is used. This gives the
2222 compiler more freedom to optimize. Here are some examples of (potentially
2223 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2224
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2225
2226<div class="doc_code">
2227<pre>
2228 %A = add %X, undef
2229 %B = sub %X, undef
2230 %C = xor %X, undef
2231Safe:
2232 %A = undef
2233 %B = undef
2234 %C = undef
2235</pre>
2236</div>
2237
2238<p>This is safe because all of the output bits are affected by the undef bits.
2239Any output bit can have a zero or one depending on the input bits.</p>
2240
2241<div class="doc_code">
2242<pre>
2243 %A = or %X, undef
2244 %B = and %X, undef
2245Safe:
2246 %A = -1
2247 %B = 0
2248Unsafe:
2249 %A = undef
2250 %B = undef
2251</pre>
2252</div>
2253
2254<p>These logical operations have bits that are not always affected by the input.
2255For example, if "%X" has a zero bit, then the output of the 'and' operation will
2256always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2257such, 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]2258However, it is safe to assume that all bits of the undef could be 0, and
2259optimize the and to 0. Likewise, it is safe to assume that all the bits of
2260the 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]2261-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2262
2263<div class="doc_code">
2264<pre>
2265 %A = select undef, %X, %Y
2266 %B = select undef, 42, %Y
2267 %C = select %X, %Y, undef
2268Safe:
2269 %A = %X (or %Y)
2270 %B = 42 (or %Y)
2271 %C = %Y
2272Unsafe:
2273 %A = undef
2274 %B = undef
2275 %C = undef
2276</pre>
2277</div>
2278
2279<p>This set of examples show that undefined select (and conditional branch)
2280conditions can go "either way" but they have to come from one of the two
2281operands. In the %A example, if %X and %Y were both known to have a clear low
2282bit, then %A would have to have a cleared low bit. However, in the %C example,
2283the optimizer is allowed to assume that the undef operand could be the same as
2284%Y, allowing the whole select to be eliminated.</p>
2285
2286
2287<div class="doc_code">
2288<pre>
2289 %A = xor undef, undef
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2290
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2291 %B = undef
2292 %C = xor %B, %B
2293
2294 %D = undef
2295 %E = icmp lt %D, 4
2296 %F = icmp gte %D, 4
2297
2298Safe:
2299 %A = undef
2300 %B = undef
2301 %C = undef
2302 %D = undef
2303 %E = undef
2304 %F = undef
2305</pre>
2306</div>
2307
2308<p>This example points out that two undef operands are not necessarily the same.
2309This can be surprising to people (and also matches C semantics) where they
2310assume that "X^X" is always zero, even if X is undef. This isn't true for a
2311number of reasons, but the short answer is that an undef "variable" can
2312arbitrarily change its value over its "live range". This is true because the
2313"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2314logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2315so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2316to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2317would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2318
2319<div class="doc_code">
2320<pre>
2321 %A = fdiv undef, %X
2322 %B = fdiv %X, undef
2323Safe:
2324 %A = undef
2325b: unreachable
2326</pre>
2327</div>
2328
2329<p>These examples show the crucial difference between an <em>undefined
2330value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2331allowed to have an arbitrary bit-pattern. This means that the %A operation
2332can be constant folded to undef because the undef could be an SNaN, and fdiv is
2333not (currently) defined on SNaN's. However, in the second example, we can make
2334a more aggressive assumption: because the undef is allowed to be an arbitrary
2335value, 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]2336has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2337does not execute at all. This allows us to delete the divide and all code after
2338it: since the undefined operation "can't happen", the optimizer can assume that
2339it occurs in dead code.
2340</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2341
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2342<div class="doc_code">
2343<pre>
2344a: store undef -> %X
2345b: store %X -> undef
2346Safe:
2347a: &lt;deleted&gt;
2348b: unreachable
2349</pre>
2350</div>
2351
2352<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2353can be assumed to not have any effect: we can assume that the value is
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2354overwritten with bits that happen to match what was already there. However, a
2355store "to" an undefined location could clobber arbitrary memory, therefore, it
2356has undefined behavior.</p>
2357
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2358</div>
2359
2360<!-- ======================================================================= -->
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2361<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2362<div class="doc_text">
2363
Dan Gohman67bf37f2010-04-26 20:21:21 +0000[diff] [blame]2364<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2365 instead of representing an unspecified bit pattern, they represent the
2366 fact that an instruction or constant expression which cannot evoke side
2367 effects has nevertheless detected a condition which results in undefined
Dan Gohman67bf37f2010-04-26 20:21:21 +0000[diff] [blame]2368 behavior.</p>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2369
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2370<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]2371 only exist when produced by operations such as
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2372 <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]2373
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2374<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2375
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2376<p>
2377<ul>
2378<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2379 their operands.</li>
2380
2381<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2382 to their dynamic predecessor basic block.</li>
2383
2384<li>Function arguments depend on the corresponding actual argument values in
2385 the dynamic callers of their functions.</li>
2386
2387<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2388 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2389 control back to them.</li>
2390
Dan Gohman5e7b8fb2010-05-03 14:55:22 +0000[diff] [blame]2391<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2392 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2393 or exception-throwing call instructions that dynamically transfer control
2394 back to them.</li>
2395
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2396<li>Non-volatile loads and stores depend on the most recent stores to all of the
2397 referenced memory addresses, following the order in the IR
2398 (including loads and stores implied by intrinsics such as
2399 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2400
Dan Gohmane2c06b62010-05-03 14:59:34 +0000[diff] [blame]2401<!-- TODO: In the case of multiple threads, this only applies if the store
2402 "happens-before" the load or store. -->
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2403
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2404<!-- TODO: floating-point exception state -->
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2405
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2406<li>An instruction with externally visible side effects depends on the most
2407 recent preceding instruction with externally visible side effects, following
Dan Gohman8c6704c2010-07-06 15:26:33 +0000[diff] [blame]2408 the order in the IR. (This includes
2409 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2410
Dan Gohman5e7b8fb2010-05-03 14:55:22 +0000[diff] [blame]2411<li>An instruction <i>control-depends</i> on a
2412 <a href="#terminators">terminator instruction</a>
2413 if the terminator instruction has multiple successors and the instruction
2414 is always executed when control transfers to one of the successors, and
2415 may not be executed when control is transfered to another.</li>
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2416
2417<li>Dependence is transitive.</li>
2418
2419</ul>
2420</p>
2421
2422<p>Whenever a trap value is generated, all values which depend on it evaluate
2423 to trap. If they have side effects, the evoke their side effects as if each
2424 operand with a trap value were undef. If they have externally-visible side
2425 effects, the behavior is undefined.</p>
2426
2427<p>Here are some examples:</p>
Dan Gohman54884272010-04-26 20:54:53 +0000[diff] [blame]2428
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2429<div class="doc_code">
2430<pre>
2431entry:
2432 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2433 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2434 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2435 store i32 0, i32* %trap_yet_again ; undefined behavior
2436
2437 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2438 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2439
2440 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2441
2442 %narrowaddr = bitcast i32* @g to i16*
2443 %wideaddr = bitcast i32* @g to i64*
2444 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2445 %trap4 = load i64* %widaddr ; Returns a trap value.
2446
2447 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2448 %br i1 %cmp, %true, %end ; Branch to either destination.
2449
2450true:
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2451 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2452 ; it has undefined behavior.
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2453 br label %end
2454
2455end:
2456 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2457 ; Both edges into this PHI are
2458 ; control-dependent on %cmp, so this
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2459 ; always results in a trap value.
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2460
2461 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2462 ; so this is defined (ignoring earlier
2463 ; undefined behavior in this example).
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2464</pre>
2465</div>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2466
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2467</div>
2468
2469<!-- ======================================================================= -->
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2470<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2471 Blocks</a></div>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2472<div class="doc_text">
2473
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2474<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2475
2476<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner24f2e852009-10-27 21:49:40 +0000[diff] [blame]2477 basic block in the specified function, and always has an i8* type. Taking
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2478 the address of the entry block is illegal.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2479
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2480<p>This value only has defined behavior when used as an operand to the
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2481 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2482 against null. Pointer equality tests between labels addresses is undefined
2483 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2484 equal to the null pointer. This may also be passed around as an opaque
2485 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner0bae7b32009-10-27 21:44:20 +0000[diff] [blame]2486 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2487 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2488
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2489<p>Finally, some targets may provide defined semantics when
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2490 using the value as the operand to an inline assembly, but that is target
2491 specific.
2492 </p>
2493
2494</div>
2495
2496
2497<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2498<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2499</div>
2500
2501<div class="doc_text">
2502
2503<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2504 to be used as constants. Constant expressions may be of
2505 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2506 operation that does not have side effects (e.g. load and call are not
2507 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2508
2509<dl>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2510 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2511 <dd>Truncate a constant to another type. The bit size of CST must be larger
2512 than the bit size of TYPE. Both types must be integers.</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>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2515 <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^]2516 smaller than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2517
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2518 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2519 <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^]2520 smaller than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2521
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2522 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2523 <dd>Truncate a floating point constant to another floating point type. The
2524 size of CST must be larger than the size of TYPE. Both types must be
2525 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2526
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2527 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2528 <dd>Floating point extend a constant to another type. The size of CST must be
2529 smaller or equal to the size of TYPE. Both types must be floating
2530 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2531
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2532 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2533 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2534 constant. TYPE must be a scalar or vector integer type. CST must be of
2535 scalar or vector floating point type. Both CST and TYPE must be scalars,
2536 or vectors of the same number of elements. If the value won't fit in the
2537 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2538
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2539 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2540 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2541 constant. TYPE must be a scalar or vector integer type. CST must be of
2542 scalar or vector floating point type. Both CST and TYPE must be scalars,
2543 or vectors of the same number of elements. If the value won't fit in the
2544 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2545
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2546 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2547 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2548 constant. TYPE must be a scalar or vector floating point type. CST must be
2549 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2550 vectors of the same number of elements. If the value won't fit in the
2551 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2552
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2553 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2554 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2555 constant. TYPE must be a scalar or vector floating point type. CST must be
2556 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2557 vectors of the same number of elements. If the value won't fit in the
2558 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2559
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2560 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2561 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2562 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2563 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2564 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2565
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2566 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2567 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2568 type. CST must be of integer type. The CST value is zero extended,
2569 truncated, or unchanged to make it fit in a pointer size. This one is
2570 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2571
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2572 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2573 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2574 are the same as those for the <a href="#i_bitcast">bitcast
2575 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2576
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2577 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2578 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2579 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2580 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2581 instruction, the index list may have zero or more indexes, which are
2582 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2583
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2584 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2585 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2586
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2587 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2588 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2589
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2590 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2591 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2592
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2593 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2594 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2595 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2596
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2597 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2598 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2599 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2600
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2601 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2602 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2603 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2604
Nick Lewyckyeb94e312010-05-29 06:44:15 +0000[diff] [blame]2605 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2606 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2607 constants. The index list is interpreted in a similar manner as indices in
2608 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2609 index value must be specified.</dd>
2610
2611 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2612 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2613 constants. The index list is interpreted in a similar manner as indices in
2614 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2615 index value must be specified.</dd>
2616
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2617 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2618 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2619 be any of the <a href="#binaryops">binary</a>
2620 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2621 on operands are the same as those for the corresponding instruction
2622 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2623</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2624
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2625</div>
2626
2627<!-- *********************************************************************** -->
2628<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2629<!-- *********************************************************************** -->
2630
2631<!-- ======================================================================= -->
2632<div class="doc_subsection">
2633<a name="inlineasm">Inline Assembler Expressions</a>
2634</div>
2635
2636<div class="doc_text">
2637
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2638<p>LLVM supports inline assembler expressions (as opposed
2639 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2640 a special value. This value represents the inline assembler as a string
2641 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2642 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2643 expression has side effects, and a flag indicating whether the function
2644 containing the asm needs to align its stack conservatively. An example
2645 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2646
2647<div class="doc_code">
2648<pre>
2649i32 (i32) asm "bswap $0", "=r,r"
2650</pre>
2651</div>
2652
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2653<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2654 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2655 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2656
2657<div class="doc_code">
2658<pre>
2659%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2660</pre>
2661</div>
2662
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2663<p>Inline asms with side effects not visible in the constraint list must be
2664 marked as having side effects. This is done through the use of the
2665 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2666
2667<div class="doc_code">
2668<pre>
2669call void asm sideeffect "eieio", ""()
2670</pre>
2671</div>
2672
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2673<p>In some cases inline asms will contain code that will not work unless the
2674 stack is aligned in some way, such as calls or SSE instructions on x86,
2675 yet will not contain code that does that alignment within the asm.
2676 The compiler should make conservative assumptions about what the asm might
2677 contain and should generate its usual stack alignment code in the prologue
2678 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2679
2680<div class="doc_code">
2681<pre>
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2682call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2683</pre>
2684</div>
2685
2686<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2687 first.</p>
2688
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2689<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2690 documented here. Constraints on what can be done (e.g. duplication, moving,
2691 etc need to be documented). This is probably best done by reference to
2692 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnerbafc8372010-04-07 05:38:05 +0000[diff] [blame]2693</div>
2694
2695<div class="doc_subsubsection">
2696<a name="inlineasm_md">Inline Asm Metadata</a>
2697</div>
2698
2699<div class="doc_text">
2700
2701<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2702 attached to it that contains a constant integer. If present, the code
2703 generator will use the integer as the location cookie value when report
2704 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohmanfde3cd72010-04-28 00:36:01 +0000[diff] [blame]2705 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnerbafc8372010-04-07 05:38:05 +0000[diff] [blame]2706 source code that produced it. For example:</p>
2707
2708<div class="doc_code">
2709<pre>
2710call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2711...
2712!42 = !{ i32 1234567 }
2713</pre>
2714</div>
2715
2716<p>It is up to the front-end to make sense of the magic numbers it places in the
2717 IR.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2718
2719</div>
2720
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2721<!-- ======================================================================= -->
2722<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2723 Strings</a>
2724</div>
2725
2726<div class="doc_text">
2727
2728<p>LLVM IR allows metadata to be attached to instructions in the program that
2729 can convey extra information about the code to the optimizers and code
2730 generator. One example application of metadata is source-level debug
2731 information. There are two metadata primitives: strings and nodes. All
2732 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2733 preceding exclamation point ('<tt>!</tt>').</p>
2734
2735<p>A metadata string is a string surrounded by double quotes. It can contain
2736 any character by escaping non-printable characters with "\xx" where "xx" is
2737 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2738
2739<p>Metadata nodes are represented with notation similar to structure constants
2740 (a comma separated list of elements, surrounded by braces and preceded by an
2741 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2742 10}</tt>". Metadata nodes can have any values as their operand.</p>
2743
2744<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2745 metadata nodes, which can be looked up in the module symbol table. For
2746 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2747
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2748<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2749 function is using two metadata arguments.
2750
2751 <div class="doc_code">
2752 <pre>
2753 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2754 </pre>
2755 </div></p>
2756
2757<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2758 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2759
2760 <div class="doc_code">
2761 <pre>
2762 %indvar.next = add i64 %indvar, 1, !dbg !21
2763 </pre>
2764 </div></p>
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2765</div>
2766
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2767
2768<!-- *********************************************************************** -->
2769<div class="doc_section">
2770 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2771</div>
2772<!-- *********************************************************************** -->
2773
2774<p>LLVM has a number of "magic" global variables that contain data that affect
2775code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2776of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2777section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2778by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2779
2780<!-- ======================================================================= -->
2781<div class="doc_subsection">
2782<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2783</div>
2784
2785<div class="doc_text">
2786
2787<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2788href="#linkage_appending">appending linkage</a>. This array contains a list of
2789pointers to global variables and functions which may optionally have a pointer
2790cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2791
2792<pre>
2793 @X = global i8 4
2794 @Y = global i32 123
2795
2796 @llvm.used = appending global [2 x i8*] [
2797 i8* @X,
2798 i8* bitcast (i32* @Y to i8*)
2799 ], section "llvm.metadata"
2800</pre>
2801
2802<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2803compiler, assembler, and linker are required to treat the symbol as if there is
2804a reference to the global that it cannot see. For example, if a variable has
2805internal linkage and no references other than that from the <tt>@llvm.used</tt>
2806list, it cannot be deleted. This is commonly used to represent references from
2807inline asms and other things the compiler cannot "see", and corresponds to
2808"attribute((used))" in GNU C.</p>
2809
2810<p>On some targets, the code generator must emit a directive to the assembler or
2811object file to prevent the assembler and linker from molesting the symbol.</p>
2812
2813</div>
2814
2815<!-- ======================================================================= -->
2816<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2817<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2818</div>
2819
2820<div class="doc_text">
2821
2822<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2823<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2824touching the symbol. On targets that support it, this allows an intelligent
2825linker to optimize references to the symbol without being impeded as it would be
2826by <tt>@llvm.used</tt>.</p>
2827
2828<p>This is a rare construct that should only be used in rare circumstances, and
2829should not be exposed to source languages.</p>
2830
2831</div>
2832
2833<!-- ======================================================================= -->
2834<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2835<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2836</div>
2837
2838<div class="doc_text">
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2839<pre>
2840%0 = type { i32, void ()* }
David Chisnalla07a3c22010-04-30 19:27:35 +0000[diff] [blame]2841@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2842</pre>
2843<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.
2844</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2845
2846</div>
2847
2848<!-- ======================================================================= -->
2849<div class="doc_subsection">
2850<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2851</div>
2852
2853<div class="doc_text">
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2854<pre>
2855%0 = type { i32, void ()* }
David Chisnalla07a3c22010-04-30 19:27:35 +0000[diff] [blame]2856@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2857</pre>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2858
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2859<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.
2860</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2861
2862</div>
2863
2864
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2865<!-- *********************************************************************** -->
2866<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2867<!-- *********************************************************************** -->
2868
2869<div class="doc_text">
2870
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2871<p>The LLVM instruction set consists of several different classifications of
2872 instructions: <a href="#terminators">terminator
2873 instructions</a>, <a href="#binaryops">binary instructions</a>,
2874 <a href="#bitwiseops">bitwise binary instructions</a>,
2875 <a href="#memoryops">memory instructions</a>, and
2876 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2877
2878</div>
2879
2880<!-- ======================================================================= -->
2881<div class="doc_subsection"> <a name="terminators">Terminator
2882Instructions</a> </div>
2883
2884<div class="doc_text">
2885
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2886<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2887 in a program ends with a "Terminator" instruction, which indicates which
2888 block should be executed after the current block is finished. These
2889 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2890 control flow, not values (the one exception being the
2891 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2892
Duncan Sands048d8062010-04-15 20:35:54 +0000[diff] [blame]2893<p>There are seven different terminator instructions: the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2894 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2895 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2896 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendlingb4ae2292009-11-02 00:25:26 +0000[diff] [blame]2897 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2898 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2899 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2900 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2901
2902</div>
2903
2904<!-- _______________________________________________________________________ -->
2905<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2906Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2907
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2908<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2909
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2910<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2911<pre>
2912 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]2913 ret void <i>; Return from void function</i>
2914</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2915
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2916<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2917<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2918 a value) from a function back to the caller.</p>
2919
2920<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2921 value and then causes control flow, and one that just causes control flow to
2922 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2923
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2924<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2925<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2926 return value. The type of the return value must be a
2927 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2928
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2929<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2930 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2931 value or a return value with a type that does not match its type, or if it
2932 has a void return type and contains a '<tt>ret</tt>' instruction with a
2933 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2934
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2935<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2936<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2937 the calling function's context. If the caller is a
2938 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2939 instruction after the call. If the caller was an
2940 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2941 the beginning of the "normal" destination block. If the instruction returns
2942 a value, that value shall set the call or invoke instruction's return
2943 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2944
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2945<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2946<pre>
2947 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2948 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2949 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]2950</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2951
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2952</div>
2953<!-- _______________________________________________________________________ -->
2954<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2955
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2956<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2957
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2958<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2959<pre>
2960 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]2961</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2962
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2963<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2964<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2965 different basic block in the current function. There are two forms of this
2966 instruction, corresponding to a conditional branch and an unconditional
2967 branch.</p>
2968
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2969<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2970<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2971 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2972 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2973 target.</p>
2974
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2975<h5>Semantics:</h5>
2976<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2977 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2978 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2979 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2980
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2981<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2982<pre>
2983Test:
2984 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2985 br i1 %cond, label %IfEqual, label %IfUnequal
2986IfEqual:
2987 <a href="#i_ret">ret</a> i32 1
2988IfUnequal:
2989 <a href="#i_ret">ret</a> i32 0
2990</pre>
2991
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2992</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2993
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2994<!-- _______________________________________________________________________ -->
2995<div class="doc_subsubsection">
2996 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2997</div>
2998
2999<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3000
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3001<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3002<pre>
3003 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3004</pre>
3005
3006<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3007<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]3008 several different places. It is a generalization of the '<tt>br</tt>'
3009 instruction, allowing a branch to occur to one of many possible
3010 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3011
3012<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3013<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3014 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3015 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3016 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3017
3018<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3019<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3020 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3021 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]3022 transferred to the corresponding destination; otherwise, control flow is
3023 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3024
3025<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3026<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3027 <tt>switch</tt> instruction, this instruction may be code generated in
3028 different ways. For example, it could be generated as a series of chained
3029 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3030
3031<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3032<pre>
3033 <i>; Emulate a conditional br instruction</i>
3034 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]3035 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3036
3037 <i>; Emulate an unconditional br instruction</i>
3038 switch i32 0, label %dest [ ]
3039
3040 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]3041 switch i32 %val, label %otherwise [ i32 0, label %onzero
3042 i32 1, label %onone
3043 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3044</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3045
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3046</div>
3047
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3048
3049<!-- _______________________________________________________________________ -->
3050<div class="doc_subsubsection">
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]3051 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3052</div>
3053
3054<div class="doc_text">
3055
3056<h5>Syntax:</h5>
3057<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]3058 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]3059</pre>
3060
3061<h5>Overview:</h5>
3062
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]3063<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3064 within the current function, whose address is specified by
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]3065 "<tt>address</tt>". Address must be derived from a <a
3066 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3067
3068<h5>Arguments:</h5>
3069
3070<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3071 rest of the arguments indicate the full set of possible destinations that the
3072 address may point to. Blocks are allowed to occur multiple times in the
3073 destination list, though this isn't particularly useful.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3074
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3075<p>This destination list is required so that dataflow analysis has an accurate
3076 understanding of the CFG.</p>
3077
3078<h5>Semantics:</h5>
3079
3080<p>Control transfers to the block specified in the address argument. All
3081 possible destination blocks must be listed in the label list, otherwise this
3082 instruction has undefined behavior. This implies that jumps to labels
3083 defined in other functions have undefined behavior as well.</p>
3084
3085<h5>Implementation:</h5>
3086
3087<p>This is typically implemented with a jump through a register.</p>
3088
3089<h5>Example:</h5>
3090<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]3091 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3092</pre>
3093
3094</div>
3095
3096
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3097<!-- _______________________________________________________________________ -->
3098<div class="doc_subsubsection">
3099 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3100</div>
3101
3102<div class="doc_text">
3103
3104<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3105<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]3106 &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]3107 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
3108</pre>
3109
3110<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3111<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3112 function, with the possibility of control flow transfer to either the
3113 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3114 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3115 control flow will return to the "normal" label. If the callee (or any
3116 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3117 instruction, control is interrupted and continued at the dynamically nearest
3118 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3119
3120<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3121<p>This instruction requires several arguments:</p>
3122
3123<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3124 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3125 convention</a> the call should use. If none is specified, the call
3126 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]3127
3128 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3129 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3130 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]3131
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3132 <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]3133 function value being invoked. In most cases, this is a direct function
3134 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3135 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3136
3137 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3138 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3139
3140 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]3141 signature argument types and parameter attributes. All arguments must be
3142 of <a href="#t_firstclass">first class</a> type. If the function
3143 signature indicates the function accepts a variable number of arguments,
3144 the extra arguments can be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3145
3146 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3147 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3148
3149 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3150 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3151
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]3152 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3153 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3154 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3155</ol>
3156
3157<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3158<p>This instruction is designed to operate as a standard
3159 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3160 primary difference is that it establishes an association with a label, which
3161 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3162
3163<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3164 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3165 exception. Additionally, this is important for implementation of
3166 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3167
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3168<p>For the purposes of the SSA form, the definition of the value returned by the
3169 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3170 block to the "normal" label. If the callee unwinds then no return value is
3171 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]3172
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]3173<p>Note that the code generator does not yet completely support unwind, and
3174that the invoke/unwind semantics are likely to change in future versions.</p>
3175
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3176<h5>Example:</h5>
3177<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]3178 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3179 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]3180 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3181 unwind label %TestCleanup <i>; {i32}:retval set</i>
3182</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3183
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3184</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3185
3186<!-- _______________________________________________________________________ -->
3187
3188<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3189Instruction</a> </div>
3190
3191<div class="doc_text">
3192
3193<h5>Syntax:</h5>
3194<pre>
3195 unwind
3196</pre>
3197
3198<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3199<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3200 at the first callee in the dynamic call stack which used
3201 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3202 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3203
3204<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3205<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3206 immediately halt. The dynamic call stack is then searched for the
3207 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3208 Once found, execution continues at the "exceptional" destination block
3209 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3210 instruction in the dynamic call chain, undefined behavior results.</p>
3211
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]3212<p>Note that the code generator does not yet completely support unwind, and
3213that the invoke/unwind semantics are likely to change in future versions.</p>
3214
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3215</div>
3216
3217<!-- _______________________________________________________________________ -->
3218
3219<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3220Instruction</a> </div>
3221
3222<div class="doc_text">
3223
3224<h5>Syntax:</h5>
3225<pre>
3226 unreachable
3227</pre>
3228
3229<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3230<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3231 instruction is used to inform the optimizer that a particular portion of the
3232 code is not reachable. This can be used to indicate that the code after a
3233 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3234
3235<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3236<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3238</div>
3239
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3240<!-- ======================================================================= -->
3241<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3242
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3243<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3244
3245<p>Binary operators are used to do most of the computation in a program. They
3246 require two operands of the same type, execute an operation on them, and
3247 produce a single value. The operands might represent multiple data, as is
3248 the case with the <a href="#t_vector">vector</a> data type. The result value
3249 has the same type as its operands.</p>
3250
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3251<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3252
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3253</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3254
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3255<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3256<div class="doc_subsubsection">
3257 <a name="i_add">'<tt>add</tt>' Instruction</a>
3258</div>
3259
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3260<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3261
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3262<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3263<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3264 &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]3265 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3266 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3267 &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]3268</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3269
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3270<h5>Overview:</h5>
3271<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3272
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3273<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3274<p>The two arguments to the '<tt>add</tt>' instruction must
3275 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3276 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3277
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3278<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3279<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3280
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3281<p>If the sum has unsigned overflow, the result returned is the mathematical
3282 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]3283
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3284<p>Because LLVM integers use a two's complement representation, this instruction
3285 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3286
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3287<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3288 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3289 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3290 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3291 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3292
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3293<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3294<pre>
3295 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3296</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3298</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3299
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3300<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3301<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3302 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3303</div>
3304
3305<div class="doc_text">
3306
3307<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3308<pre>
3309 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3310</pre>
3311
3312<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3313<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3314
3315<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3316<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3317 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3318 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3319
3320<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3321<p>The value produced is the floating point sum of the two operands.</p>
3322
3323<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3324<pre>
3325 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3326</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3327
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3328</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3329
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3330<!-- _______________________________________________________________________ -->
3331<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3332 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3333</div>
3334
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3335<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3336
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3337<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3338<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3339 &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]3340 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3341 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3342 &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]3343</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3344
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3345<h5>Overview:</h5>
3346<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3347 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3348
3349<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3350 '<tt>neg</tt>' instruction present in most other intermediate
3351 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3352
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3353<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3354<p>The two arguments to the '<tt>sub</tt>' instruction must
3355 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3356 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3357
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3358<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3359<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3360
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3361<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3362 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3363 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3364
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3365<p>Because LLVM integers use a two's complement representation, this instruction
3366 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3367
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3368<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3369 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3370 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3371 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3372 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3373
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3374<h5>Example:</h5>
3375<pre>
3376 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
3377 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
3378</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3379
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3380</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3381
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3382<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3383<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3384 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3385</div>
3386
3387<div class="doc_text">
3388
3389<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3390<pre>
3391 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3392</pre>
3393
3394<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3395<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3396 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3397
3398<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3399 '<tt>fneg</tt>' instruction present in most other intermediate
3400 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3401
3402<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]3403<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3404 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3405 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3406
3407<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3408<p>The value produced is the floating point difference of the two operands.</p>
3409
3410<h5>Example:</h5>
3411<pre>
3412 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3413 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3414</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3415
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3416</div>
3417
3418<!-- _______________________________________________________________________ -->
3419<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3420 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3421</div>
3422
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3423<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3424
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3425<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3426<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3427 &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]3428 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3429 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3430 &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]3431</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3432
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3433<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3434<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3435
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3436<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3437<p>The two arguments to the '<tt>mul</tt>' instruction must
3438 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3439 integer values. Both arguments must have identical types.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3440
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3441<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3442<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3443
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3444<p>If the result of the multiplication has unsigned overflow, the result
3445 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3446 width of the result.</p>
3447
3448<p>Because LLVM integers use a two's complement representation, and the result
3449 is the same width as the operands, this instruction returns the correct
3450 result for both signed and unsigned integers. If a full product
3451 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3452 be sign-extended or zero-extended as appropriate to the width of the full
3453 product.</p>
3454
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3455<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3456 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3457 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3458 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3459 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3460
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3461<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3462<pre>
3463 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3464</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3465
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3466</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3467
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3468<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3469<div class="doc_subsubsection">
3470 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3471</div>
3472
3473<div class="doc_text">
3474
3475<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3476<pre>
3477 &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]3478</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3479
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3480<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3481<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3482
3483<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3484<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3485 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3486 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3487
3488<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3489<p>The value produced is the floating point product of the two operands.</p>
3490
3491<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3492<pre>
3493 &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]3494</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3495
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3496</div>
3497
3498<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3499<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3500</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3501
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3502<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3503
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3504<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3505<pre>
3506 &lt;result&gt; = 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]3507</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3508
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3509<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3510<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3511
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3512<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3513<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3514 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3515 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3516
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3517<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3518<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3519
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3520<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3521 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3522
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3523<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3524
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3525<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3526<pre>
3527 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3528</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3530</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3531
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3532<!-- _______________________________________________________________________ -->
3533<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3534</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3535
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3536<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3537
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3538<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3539<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3540 &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]3541 &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]3542</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3543
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3544<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3545<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3546
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3547<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3548<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3549 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3550 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3551
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3552<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3553<p>The value produced is the signed integer quotient of the two operands rounded
3554 towards zero.</p>
3555
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3556<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3557 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3558
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3559<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3560 undefined behavior; this is a rare case, but can occur, for example, by doing
3561 a 32-bit division of -2147483648 by -1.</p>
3562
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3563<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanf7263862010-04-23 15:23:32 +0000[diff] [blame]3564 <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]3565 be rounded.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3566
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3567<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3568<pre>
3569 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3570</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3571
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3572</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3573
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3574<!-- _______________________________________________________________________ -->
3575<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3576Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3577
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3578<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3579
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3580<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3581<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3582 &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]3583</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3584
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3585<h5>Overview:</h5>
3586<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3587
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3588<h5>Arguments:</h5>
3589<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3590 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3591 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3592
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3593<h5>Semantics:</h5>
3594<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3595
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3596<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3597<pre>
3598 &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]3599</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3601</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3602
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3603<!-- _______________________________________________________________________ -->
3604<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3605</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3606
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3607<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3608
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3609<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3610<pre>
3611 &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]3612</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3613
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3614<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3615<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3616 division of its two arguments.</p>
3617
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3618<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3619<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3620 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3621 values. Both arguments must have identical types.</p>
3622
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3623<h5>Semantics:</h5>
3624<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3625 This instruction always performs an unsigned division to get the
3626 remainder.</p>
3627
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3628<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3629 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3630
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3631<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3632
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3633<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3634<pre>
3635 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3636</pre>
3637
3638</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3640<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3641<div class="doc_subsubsection">
3642 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3643</div>
3644
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3645<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3646
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3647<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3648<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3649 &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]3650</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3651
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3652<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3653<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3654 division of its two operands. This instruction can also take
3655 <a href="#t_vector">vector</a> versions of the values in which case the
3656 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3657
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3658<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3659<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3660 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3661 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3663<h5>Semantics:</h5>
3664<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3665 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3666 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3667 a value. For more information about the difference,
3668 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3669 Math Forum</a>. For a table of how this is implemented in various languages,
3670 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3671 Wikipedia: modulo operation</a>.</p>
3672
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3673<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3674 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3675
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3676<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3677 Overflow also leads to undefined behavior; this is a rare case, but can
3678 occur, for example, by taking the remainder of a 32-bit division of
3679 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3680 lets srem be implemented using instructions that return both the result of
3681 the division and the remainder.)</p>
3682
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3683<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3684<pre>
3685 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3686</pre>
3687
3688</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3689
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3690<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3691<div class="doc_subsubsection">
3692 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3693
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3694<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3695
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3696<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3697<pre>
3698 &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]3699</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3700
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3701<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3702<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3703 its two operands.</p>
3704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3705<h5>Arguments:</h5>
3706<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3707 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3708 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3709
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3710<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3711<p>This instruction returns the <i>remainder</i> of a division. The remainder
3712 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3713
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3714<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3715<pre>
3716 &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]3717</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3718
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3719</div>
3720
3721<!-- ======================================================================= -->
3722<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3723Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3724
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3725<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3726
3727<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3728 program. They are generally very efficient instructions and can commonly be
3729 strength reduced from other instructions. They require two operands of the
3730 same type, execute an operation on them, and produce a single value. The
3731 resulting value is the same type as its operands.</p>
3732
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3733</div>
3734
3735<!-- _______________________________________________________________________ -->
3736<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3737Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3738
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3739<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3740
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3741<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3742<pre>
3743 &lt;result&gt; = 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]3744</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3745
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3746<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3747<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3748 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3749
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3750<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3751<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3752 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3753 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3754
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3755<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3756<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3757 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3758 is (statically or dynamically) negative or equal to or larger than the number
3759 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3760 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3761 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3762
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3763<h5>Example:</h5>
3764<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3765 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3766 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3767 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3768 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3769 &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]3770</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3771
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3772</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3773
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3774<!-- _______________________________________________________________________ -->
3775<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3776Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3777
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3778<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3779
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3780<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3781<pre>
3782 &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]3783</pre>
3784
3785<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3786<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3787 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3788
3789<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3790<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3791 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3792 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3793
3794<h5>Semantics:</h5>
3795<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3796 significant bits of the result will be filled with zero bits after the shift.
3797 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3798 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3799 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3800 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3801
3802<h5>Example:</h5>
3803<pre>
3804 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3805 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3806 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3807 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3808 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3809 &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]3810</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3811
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3812</div>
3813
3814<!-- _______________________________________________________________________ -->
3815<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3816Instruction</a> </div>
3817<div class="doc_text">
3818
3819<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3820<pre>
3821 &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]3822</pre>
3823
3824<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3825<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3826 operand shifted to the right a specified number of bits with sign
3827 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3828
3829<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3830<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3831 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3832 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3833
3834<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3835<p>This instruction always performs an arithmetic shift right operation, The
3836 most significant bits of the result will be filled with the sign bit
3837 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3838 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3839 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3840 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3841
3842<h5>Example:</h5>
3843<pre>
3844 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3845 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3846 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3847 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3848 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3849 &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]3850</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3851
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3852</div>
3853
3854<!-- _______________________________________________________________________ -->
3855<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3856Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3857
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3858<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3859
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3860<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3861<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3862 &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]3863</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3864
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3865<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3866<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3867 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3868
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3869<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3870<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3871 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3872 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3873
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3874<h5>Semantics:</h5>
3875<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3876
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3877<table border="1" cellspacing="0" cellpadding="4">
3878 <tbody>
3879 <tr>
3880 <td>In0</td>
3881 <td>In1</td>
3882 <td>Out</td>
3883 </tr>
3884 <tr>
3885 <td>0</td>
3886 <td>0</td>
3887 <td>0</td>
3888 </tr>
3889 <tr>
3890 <td>0</td>
3891 <td>1</td>
3892 <td>0</td>
3893 </tr>
3894 <tr>
3895 <td>1</td>
3896 <td>0</td>
3897 <td>0</td>
3898 </tr>
3899 <tr>
3900 <td>1</td>
3901 <td>1</td>
3902 <td>1</td>
3903 </tr>
3904 </tbody>
3905</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3906
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3907<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3908<pre>
3909 &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]3910 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3911 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3912</pre>
3913</div>
3914<!-- _______________________________________________________________________ -->
3915<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3916
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3917<div class="doc_text">
3918
3919<h5>Syntax:</h5>
3920<pre>
3921 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3922</pre>
3923
3924<h5>Overview:</h5>
3925<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3926 two operands.</p>
3927
3928<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3929<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3930 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3931 values. Both arguments must have identical types.</p>
3932
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3933<h5>Semantics:</h5>
3934<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3935
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3936<table border="1" cellspacing="0" cellpadding="4">
3937 <tbody>
3938 <tr>
3939 <td>In0</td>
3940 <td>In1</td>
3941 <td>Out</td>
3942 </tr>
3943 <tr>
3944 <td>0</td>
3945 <td>0</td>
3946 <td>0</td>
3947 </tr>
3948 <tr>
3949 <td>0</td>
3950 <td>1</td>
3951 <td>1</td>
3952 </tr>
3953 <tr>
3954 <td>1</td>
3955 <td>0</td>
3956 <td>1</td>
3957 </tr>
3958 <tr>
3959 <td>1</td>
3960 <td>1</td>
3961 <td>1</td>
3962 </tr>
3963 </tbody>
3964</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3965
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3966<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3967<pre>
3968 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3969 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3970 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3971</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3972
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3973</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3974
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3975<!-- _______________________________________________________________________ -->
3976<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3977Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3978
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3979<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3980
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3981<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3982<pre>
3983 &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]3984</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3985
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3986<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3987<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3988 its two operands. The <tt>xor</tt> is used to implement the "one's
3989 complement" operation, which is the "~" operator in C.</p>
3990
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3991<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3992<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3993 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3994 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3995
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3996<h5>Semantics:</h5>
3997<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3998
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3999<table border="1" cellspacing="0" cellpadding="4">
4000 <tbody>
4001 <tr>
4002 <td>In0</td>
4003 <td>In1</td>
4004 <td>Out</td>
4005 </tr>
4006 <tr>
4007 <td>0</td>
4008 <td>0</td>
4009 <td>0</td>
4010 </tr>
4011 <tr>
4012 <td>0</td>
4013 <td>1</td>
4014 <td>1</td>
4015 </tr>
4016 <tr>
4017 <td>1</td>
4018 <td>0</td>
4019 <td>1</td>
4020 </tr>
4021 <tr>
4022 <td>1</td>
4023 <td>1</td>
4024 <td>0</td>
4025 </tr>
4026 </tbody>
4027</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4028
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4029<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4030<pre>
4031 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4032 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4033 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4034 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
4035</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4036
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4037</div>
4038
4039<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4040<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4041 <a name="vectorops">Vector Operations</a>
4042</div>
4043
4044<div class="doc_text">
4045
4046<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4047 target-independent manner. These instructions cover the element-access and
4048 vector-specific operations needed to process vectors effectively. While LLVM
4049 does directly support these vector operations, many sophisticated algorithms
4050 will want to use target-specific intrinsics to take full advantage of a
4051 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4052
4053</div>
4054
4055<!-- _______________________________________________________________________ -->
4056<div class="doc_subsubsection">
4057 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
4058</div>
4059
4060<div class="doc_text">
4061
4062<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4063<pre>
4064 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
4065</pre>
4066
4067<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4068<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4069 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4070
4071
4072<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4073<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4074 of <a href="#t_vector">vector</a> type. The second operand is an index
4075 indicating the position from which to extract the element. The index may be
4076 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4077
4078<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4079<p>The result is a scalar of the same type as the element type of
4080 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4081 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4082 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4083
4084<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4085<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4086 &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]4087</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4088
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4089</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4090
4091<!-- _______________________________________________________________________ -->
4092<div class="doc_subsubsection">
4093 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4094</div>
4095
4096<div class="doc_text">
4097
4098<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4099<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]4100 &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]4101</pre>
4102
4103<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4104<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4105 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4106
4107<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4108<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4109 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4110 whose type must equal the element type of the first operand. The third
4111 operand is an index indicating the position at which to insert the value.
4112 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4113
4114<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4115<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4116 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4117 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4118 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4119
4120<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4121<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4122 &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]4123</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4124
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4125</div>
4126
4127<!-- _______________________________________________________________________ -->
4128<div class="doc_subsubsection">
4129 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4130</div>
4131
4132<div class="doc_text">
4133
4134<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4135<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]4136 &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]4137</pre>
4138
4139<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4140<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4141 from two input vectors, returning a vector with the same element type as the
4142 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4143
4144<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4145<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4146 with types that match each other. The third argument is a shuffle mask whose
4147 element type is always 'i32'. The result of the instruction is a vector
4148 whose length is the same as the shuffle mask and whose element type is the
4149 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4150
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4151<p>The shuffle mask operand is required to be a constant vector with either
4152 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4153
4154<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4155<p>The elements of the two input vectors are numbered from left to right across
4156 both of the vectors. The shuffle mask operand specifies, for each element of
4157 the result vector, which element of the two input vectors the result element
4158 gets. The element selector may be undef (meaning "don't care") and the
4159 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4160
4161<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4162<pre>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4163 &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]4164 &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]4165 &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]4166 &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]4167 &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]4168 &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]4169 &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]4170 &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]4171</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4172
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4173</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4174
4175<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4176<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4177 <a name="aggregateops">Aggregate Operations</a>
4178</div>
4179
4180<div class="doc_text">
4181
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4182<p>LLVM supports several instructions for working with
4183 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4184
4185</div>
4186
4187<!-- _______________________________________________________________________ -->
4188<div class="doc_subsubsection">
4189 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4190</div>
4191
4192<div class="doc_text">
4193
4194<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4195<pre>
4196 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4197</pre>
4198
4199<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4200<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4201 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4202
4203<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4204<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4205 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4206 <a href="#t_array">array</a> type. The operands are constant indices to
4207 specify which value to extract in a similar manner as indices in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4208 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4209
4210<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4211<p>The result is the value at the position in the aggregate specified by the
4212 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4213
4214<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4215<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4216 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4217</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4218
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4219</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4220
4221<!-- _______________________________________________________________________ -->
4222<div class="doc_subsubsection">
4223 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4224</div>
4225
4226<div class="doc_text">
4227
4228<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4229<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]4230 &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]4231</pre>
4232
4233<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4234<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4235 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4236
4237<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4238<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4239 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4240 <a href="#t_array">array</a> type. The second operand is a first-class
4241 value to insert. The following operands are constant indices indicating
4242 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]4243 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4244 value to insert must have the same type as the value identified by the
4245 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4246
4247<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4248<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4249 that of <tt>val</tt> except that the value at the position specified by the
4250 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4251
4252<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4253<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]4254 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4255 %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]4256</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4257
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4258</div>
4259
4260
4261<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4262<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4263 <a name="memoryops">Memory Access and Addressing Operations</a>
4264</div>
4265
4266<div class="doc_text">
4267
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4268<p>A key design point of an SSA-based representation is how it represents
4269 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]4270 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4271 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4272
4273</div>
4274
4275<!-- _______________________________________________________________________ -->
4276<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4277 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4278</div>
4279
4280<div class="doc_text">
4281
4282<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4283<pre>
Dan Gohman3eb67d52010-05-28 01:14:11 +0000[diff] [blame]4284 &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]4285</pre>
4286
4287<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4288<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4289 currently executing function, to be automatically released when this function
4290 returns to its caller. The object is always allocated in the generic address
4291 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4292
4293<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4294<p>The '<tt>alloca</tt>' instruction
4295 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4296 runtime stack, returning a pointer of the appropriate type to the program.
4297 If "NumElements" is specified, it is the number of elements allocated,
4298 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4299 specified, the value result of the allocation is guaranteed to be aligned to
4300 at least that boundary. If not specified, or if zero, the target can choose
4301 to align the allocation on any convenient boundary compatible with the
4302 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4303
4304<p>'<tt>type</tt>' may be any sized type.</p>
4305
4306<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]4307<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4308 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4309 memory is automatically released when the function returns. The
4310 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4311 variables that must have an address available. When the function returns
4312 (either with the <tt><a href="#i_ret">ret</a></tt>
4313 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4314 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4315
4316<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4317<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]4318 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4319 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4320 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4321 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4322</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4323
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4324</div>
4325
4326<!-- _______________________________________________________________________ -->
4327<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4328Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4329
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4330<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4331
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4332<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4333<pre>
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4334 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4335 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4336 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4337</pre>
4338
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4339<h5>Overview:</h5>
4340<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4341
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4342<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4343<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4344 from which to load. The pointer must point to
4345 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4346 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]4347 number or order of execution of this <tt>load</tt> with other <a
4348 href="#volatile">volatile operations</a>.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4349
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4350<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4351 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]4352 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4353 alignment for the target. It is the responsibility of the code emitter to
4354 ensure that the alignment information is correct. Overestimating the
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4355 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4356 produce less efficient code. An alignment of 1 is always safe.</p>
4357
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4358<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4359 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4360 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4361 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4362 and code generator that this load is not expected to be reused in the cache.
4363 The code generator may select special instructions to save cache bandwidth,
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4364 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]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 location of memory pointed to is loaded. If the value being loaded is of
4368 scalar type then the number of bytes read does not exceed the minimum number
4369 of bytes needed to hold all bits of the type. For example, loading an
4370 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4371 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4372 is undefined if the value was not originally written using a store of the
4373 same type.</p>
4374
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4375<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4376<pre>
4377 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4378 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4379 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
4380</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4381
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4382</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4383
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4384<!-- _______________________________________________________________________ -->
4385<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4386Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4387
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4388<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4390<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4391<pre>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4392 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4393 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4394</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4395
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4396<h5>Overview:</h5>
4397<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4398
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4399<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4400<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4401 and an address at which to store it. The type of the
4402 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4403 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]4404 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4405 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4406 order of execution of this <tt>store</tt> with other <a
4407 href="#volatile">volatile operations</a>.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4408
4409<p>The optional constant "align" argument specifies the alignment of the
4410 operation (that is, the alignment of the memory address). A value of 0 or an
4411 omitted "align" argument means that the operation has the preferential
4412 alignment for the target. It is the responsibility of the code emitter to
4413 ensure that the alignment information is correct. Overestimating the
4414 alignment results in an undefined behavior. Underestimating the alignment may
4415 produce less efficient code. An alignment of 1 is always safe.</p>
4416
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4417<p>The optional !nontemporal metadata must reference a single metatadata
4418 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4419 value 1. The existence of the !nontemporal metatadata on the
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4420 instruction tells the optimizer and code generator that this load is
4421 not expected to be reused in the cache. The code generator may
4422 select special instructions to save cache bandwidth, such as the
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4423 MOVNT instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4424
4425
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4426<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4427<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4428 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4429 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4430 does not exceed the minimum number of bytes needed to hold all bits of the
4431 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4432 writing a value of a type like <tt>i20</tt> with a size that is not an
4433 integral number of bytes, it is unspecified what happens to the extra bits
4434 that do not belong to the type, but they will typically be overwritten.</p>
4435
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4436<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4437<pre>
4438 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4439 store i32 3, i32* %ptr <i>; yields {void}</i>
4440 %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]4441</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4442
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4443</div>
4444
4445<!-- _______________________________________________________________________ -->
4446<div class="doc_subsubsection">
4447 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4448</div>
4449
4450<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4451
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4452<h5>Syntax:</h5>
4453<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4454 &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]4455 &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]4456</pre>
4457
4458<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4459<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4460 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4461 It performs address calculation only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4462
4463<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4464<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4465 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4466 elements of the aggregate object are indexed. The interpretation of each
4467 index is dependent on the type being indexed into. The first index always
4468 indexes the pointer value given as the first argument, the second index
4469 indexes a value of the type pointed to (not necessarily the value directly
4470 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4471 indexed into must be a pointer value, subsequent types can be arrays,
4472 vectors, structs and unions. Note that subsequent types being indexed into
4473 can never be pointers, since that would require loading the pointer before
4474 continuing calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4475
4476<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]4477 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4478 integer <b>constants</b> are allowed. When indexing into an array, pointer
4479 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]4480 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4481
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4482<p>For example, let's consider a C code fragment and how it gets compiled to
4483 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4484
4485<div class="doc_code">
4486<pre>
4487struct RT {
4488 char A;
4489 int B[10][20];
4490 char C;
4491};
4492struct ST {
4493 int X;
4494 double Y;
4495 struct RT Z;
4496};
4497
4498int *foo(struct ST *s) {
4499 return &amp;s[1].Z.B[5][13];
4500}
4501</pre>
4502</div>
4503
4504<p>The LLVM code generated by the GCC frontend is:</p>
4505
4506<div class="doc_code">
4507<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4508%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4509%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4510
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4511define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4512entry:
4513 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4514 ret i32* %reg
4515}
4516</pre>
4517</div>
4518
4519<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4520<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]4521 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4522 }</tt>' type, a structure. The second index indexes into the third element
4523 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4524 i8 }</tt>' type, another structure. The third index indexes into the second
4525 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4526 array. The two dimensions of the array are subscripted into, yielding an
4527 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4528 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4529
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4530<p>Note that it is perfectly legal to index partially through a structure,
4531 returning a pointer to an inner element. Because of this, the LLVM code for
4532 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4533
4534<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4535 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4536 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4537 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4538 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4539 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4540 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4541 ret i32* %t5
4542 }
4543</pre>
4544
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4545<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohmanf7263862010-04-23 15:23:32 +0000[diff] [blame]4546 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4547 base pointer is not an <i>in bounds</i> address of an allocated object,
4548 or if any of the addresses that would be formed by successive addition of
4549 the offsets implied by the indices to the base address with infinitely
4550 precise arithmetic are not an <i>in bounds</i> address of that allocated
4551 object. The <i>in bounds</i> addresses for an allocated object are all
4552 the addresses that point into the object, plus the address one byte past
4553 the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4554
4555<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4556 the base address with silently-wrapping two's complement arithmetic, and
4557 the result value of the <tt>getelementptr</tt> may be outside the object
4558 pointed to by the base pointer. The result value may not necessarily be
4559 used to access memory though, even if it happens to point into allocated
4560 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4561 section for more information.</p>
4562
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4563<p>The getelementptr instruction is often confusing. For some more insight into
4564 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4565
4566<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4567<pre>
4568 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4569 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4570 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4571 %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]4572 <i>; yields i8*:eptr</i>
4573 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4574 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4575 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4576</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4577
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4578</div>
4579
4580<!-- ======================================================================= -->
4581<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4582</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4583
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4584<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4585
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4586<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4587 which all take a single operand and a type. They perform various bit
4588 conversions on the operand.</p>
4589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4590</div>
4591
4592<!-- _______________________________________________________________________ -->
4593<div class="doc_subsubsection">
4594 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4595</div>
4596<div class="doc_text">
4597
4598<h5>Syntax:</h5>
4599<pre>
4600 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4601</pre>
4602
4603<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4604<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4605 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4606
4607<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4608<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4609 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4610 size and type of the result, which must be
4611 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4612 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4613 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4614
4615<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4616<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4617 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4618 source size must be larger than the destination size, <tt>trunc</tt> cannot
4619 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4620
4621<h5>Example:</h5>
4622<pre>
4623 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4624 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4625 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4626</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4627
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4628</div>
4629
4630<!-- _______________________________________________________________________ -->
4631<div class="doc_subsubsection">
4632 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4633</div>
4634<div class="doc_text">
4635
4636<h5>Syntax:</h5>
4637<pre>
4638 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4639</pre>
4640
4641<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4642<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4643 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4644
4645
4646<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4647<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]4648 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4649 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]4650 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4651 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4652
4653<h5>Semantics:</h5>
4654<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]4655 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4656
4657<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4658
4659<h5>Example:</h5>
4660<pre>
4661 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4662 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4663</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4664
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4665</div>
4666
4667<!-- _______________________________________________________________________ -->
4668<div class="doc_subsubsection">
4669 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4670</div>
4671<div class="doc_text">
4672
4673<h5>Syntax:</h5>
4674<pre>
4675 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4676</pre>
4677
4678<h5>Overview:</h5>
4679<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4680
4681<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4682<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]4683 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4684 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]4685 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4686 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4687
4688<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4689<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4690 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4691 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4692
4693<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4694
4695<h5>Example:</h5>
4696<pre>
4697 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4698 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4699</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4700
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4701</div>
4702
4703<!-- _______________________________________________________________________ -->
4704<div class="doc_subsubsection">
4705 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4706</div>
4707
4708<div class="doc_text">
4709
4710<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4711<pre>
4712 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4713</pre>
4714
4715<h5>Overview:</h5>
4716<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4717 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4718
4719<h5>Arguments:</h5>
4720<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4721 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4722 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]4723 <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]4724 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4725
4726<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4727<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4728 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4729 <a href="#t_floating">floating point</a> type. If the value cannot fit
4730 within the destination type, <tt>ty2</tt>, then the results are
4731 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4732
4733<h5>Example:</h5>
4734<pre>
4735 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4736 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4737</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4738
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4739</div>
4740
4741<!-- _______________________________________________________________________ -->
4742<div class="doc_subsubsection">
4743 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4744</div>
4745<div class="doc_text">
4746
4747<h5>Syntax:</h5>
4748<pre>
4749 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4750</pre>
4751
4752<h5>Overview:</h5>
4753<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]4754 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4755
4756<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4757<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4758 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4759 a <a href="#t_floating">floating point</a> type to cast it to. The source
4760 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4761
4762<h5>Semantics:</h5>
4763<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4764 <a href="#t_floating">floating point</a> type to a larger
4765 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4766 used to make a <i>no-op cast</i> because it always changes bits. Use
4767 <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]4768
4769<h5>Example:</h5>
4770<pre>
4771 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4772 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4773</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4774
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4775</div>
4776
4777<!-- _______________________________________________________________________ -->
4778<div class="doc_subsubsection">
4779 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4780</div>
4781<div class="doc_text">
4782
4783<h5>Syntax:</h5>
4784<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4785 &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]4786</pre>
4787
4788<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4789<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4790 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4791
4792<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4793<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4794 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4795 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4796 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4797 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4798
4799<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4800<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4801 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4802 towards zero) unsigned integer value. If the value cannot fit
4803 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4804
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4805<h5>Example:</h5>
4806<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4807 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4808 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4809 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4810</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4811
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4812</div>
4813
4814<!-- _______________________________________________________________________ -->
4815<div class="doc_subsubsection">
4816 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4817</div>
4818<div class="doc_text">
4819
4820<h5>Syntax:</h5>
4821<pre>
4822 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4823</pre>
4824
4825<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4826<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4827 <a href="#t_floating">floating point</a> <tt>value</tt> to
4828 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4829
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4830<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4831<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4832 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4833 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4834 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4835 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4836
4837<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4838<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4839 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4840 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4841 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4842
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4843<h5>Example:</h5>
4844<pre>
4845 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4846 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4847 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4848</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4849
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4850</div>
4851
4852<!-- _______________________________________________________________________ -->
4853<div class="doc_subsubsection">
4854 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4855</div>
4856<div class="doc_text">
4857
4858<h5>Syntax:</h5>
4859<pre>
4860 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4861</pre>
4862
4863<h5>Overview:</h5>
4864<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4865 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4866
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4867<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4868<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]4869 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4870 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4871 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4872 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4873
4874<h5>Semantics:</h5>
4875<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4876 integer quantity and converts it to the corresponding floating point
4877 value. If the value cannot fit in the floating point value, the results are
4878 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4879
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4880<h5>Example:</h5>
4881<pre>
4882 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4883 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4884</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4885
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4886</div>
4887
4888<!-- _______________________________________________________________________ -->
4889<div class="doc_subsubsection">
4890 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4891</div>
4892<div class="doc_text">
4893
4894<h5>Syntax:</h5>
4895<pre>
4896 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4897</pre>
4898
4899<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4900<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4901 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4902
4903<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4904<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]4905 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4906 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4907 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4908 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4909
4910<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4911<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4912 quantity and converts it to the corresponding floating point value. If the
4913 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4914
4915<h5>Example:</h5>
4916<pre>
4917 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4918 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4919</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4920
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4921</div>
4922
4923<!-- _______________________________________________________________________ -->
4924<div class="doc_subsubsection">
4925 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4926</div>
4927<div class="doc_text">
4928
4929<h5>Syntax:</h5>
4930<pre>
4931 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4932</pre>
4933
4934<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4935<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4936 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4937
4938<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4939<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4940 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4941 <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]4942
4943<h5>Semantics:</h5>
4944<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4945 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4946 truncating or zero extending that value to the size of the integer type. If
4947 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4948 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4949 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4950 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4951
4952<h5>Example:</h5>
4953<pre>
4954 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4955 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4956</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4957
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4958</div>
4959
4960<!-- _______________________________________________________________________ -->
4961<div class="doc_subsubsection">
4962 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4963</div>
4964<div class="doc_text">
4965
4966<h5>Syntax:</h5>
4967<pre>
4968 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4969</pre>
4970
4971<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4972<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4973 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4974
4975<h5>Arguments:</h5>
4976<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4977 value to cast, and a type to cast it to, which must be a
4978 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4979
4980<h5>Semantics:</h5>
4981<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4982 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4983 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4984 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4985 than the size of a pointer then a zero extension is done. If they are the
4986 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4987
4988<h5>Example:</h5>
4989<pre>
4990 %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]4991 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4992 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4993</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4994
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4995</div>
4996
4997<!-- _______________________________________________________________________ -->
4998<div class="doc_subsubsection">
4999 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
5000</div>
5001<div class="doc_text">
5002
5003<h5>Syntax:</h5>
5004<pre>
5005 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5006</pre>
5007
5008<h5>Overview:</h5>
5009<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5010 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5011
5012<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5013<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5014 non-aggregate first class value, and a type to cast it to, which must also be
5015 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5016 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5017 identical. If the source type is a pointer, the destination type must also be
5018 a pointer. This instruction supports bitwise conversion of vectors to
5019 integers and to vectors of other types (as long as they have the same
5020 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5021
5022<h5>Semantics:</h5>
5023<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5024 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5025 this conversion. The conversion is done as if the <tt>value</tt> had been
5026 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5027 be converted to other pointer types with this instruction. To convert
5028 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5029 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5030
5031<h5>Example:</h5>
5032<pre>
5033 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
5034 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5035 %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]5036</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5037
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5038</div>
5039
5040<!-- ======================================================================= -->
5041<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5042
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5043<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5044
5045<p>The instructions in this category are the "miscellaneous" instructions, which
5046 defy better classification.</p>
5047
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5048</div>
5049
5050<!-- _______________________________________________________________________ -->
5051<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5052</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5053
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5054<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5055
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5056<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5057<pre>
5058 &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]5059</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5060
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5061<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5062<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5063 boolean values based on comparison of its two integer, integer vector, or
5064 pointer operands.</p>
5065
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5066<h5>Arguments:</h5>
5067<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5068 the condition code indicating the kind of comparison to perform. It is not a
5069 value, just a keyword. The possible condition code are:</p>
5070
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5071<ol>
5072 <li><tt>eq</tt>: equal</li>
5073 <li><tt>ne</tt>: not equal </li>
5074 <li><tt>ugt</tt>: unsigned greater than</li>
5075 <li><tt>uge</tt>: unsigned greater or equal</li>
5076 <li><tt>ult</tt>: unsigned less than</li>
5077 <li><tt>ule</tt>: unsigned less or equal</li>
5078 <li><tt>sgt</tt>: signed greater than</li>
5079 <li><tt>sge</tt>: signed greater or equal</li>
5080 <li><tt>slt</tt>: signed less than</li>
5081 <li><tt>sle</tt>: signed less or equal</li>
5082</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5083
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5084<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5085 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5086 typed. They must also be identical types.</p>
5087
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5088<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5089<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5090 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]5091 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]5092 result, as follows:</p>
5093
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5094<ol>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5095 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5096 <tt>false</tt> otherwise. No sign interpretation is necessary or
5097 performed.</li>
5098
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5099 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5100 <tt>false</tt> otherwise. No sign interpretation is necessary or
5101 performed.</li>
5102
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5103 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5104 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5105
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5106 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5107 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5108 to <tt>op2</tt>.</li>
5109
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5110 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5111 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5112
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5113 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5114 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5115
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5116 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5117 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5118
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5119 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5120 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5121 to <tt>op2</tt>.</li>
5122
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5123 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5124 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5125
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5126 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5127 <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]5128</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5129
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5130<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5131 values are compared as if they were integers.</p>
5132
5133<p>If the operands are integer vectors, then they are compared element by
5134 element. The result is an <tt>i1</tt> vector with the same number of elements
5135 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5136
5137<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5138<pre>
5139 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5140 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5141 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5142 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5143 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5144 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
5145</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5146
5147<p>Note that the code generator does not yet support vector types with
5148 the <tt>icmp</tt> instruction.</p>
5149
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5150</div>
5151
5152<!-- _______________________________________________________________________ -->
5153<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5154</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5155
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5156<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5157
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5158<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5159<pre>
5160 &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]5161</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5162
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5163<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5164<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5165 values based on comparison of its operands.</p>
5166
5167<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]5168(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5169
5170<p>If the operands are floating point vectors, then the result type is a vector
5171 of boolean with the same number of elements as the operands being
5172 compared.</p>
5173
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5174<h5>Arguments:</h5>
5175<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5176 the condition code indicating the kind of comparison to perform. It is not a
5177 value, just a keyword. The possible condition code are:</p>
5178
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5179<ol>
5180 <li><tt>false</tt>: no comparison, always returns false</li>
5181 <li><tt>oeq</tt>: ordered and equal</li>
5182 <li><tt>ogt</tt>: ordered and greater than </li>
5183 <li><tt>oge</tt>: ordered and greater than or equal</li>
5184 <li><tt>olt</tt>: ordered and less than </li>
5185 <li><tt>ole</tt>: ordered and less than or equal</li>
5186 <li><tt>one</tt>: ordered and not equal</li>
5187 <li><tt>ord</tt>: ordered (no nans)</li>
5188 <li><tt>ueq</tt>: unordered or equal</li>
5189 <li><tt>ugt</tt>: unordered or greater than </li>
5190 <li><tt>uge</tt>: unordered or greater than or equal</li>
5191 <li><tt>ult</tt>: unordered or less than </li>
5192 <li><tt>ule</tt>: unordered or less than or equal</li>
5193 <li><tt>une</tt>: unordered or not equal</li>
5194 <li><tt>uno</tt>: unordered (either nans)</li>
5195 <li><tt>true</tt>: no comparison, always returns true</li>
5196</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5197
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5198<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5199 <i>unordered</i> means that either operand may be a QNAN.</p>
5200
5201<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5202 a <a href="#t_floating">floating point</a> type or
5203 a <a href="#t_vector">vector</a> of floating point type. They must have
5204 identical types.</p>
5205
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5206<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]5207<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5208 according to the condition code given as <tt>cond</tt>. If the operands are
5209 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]5210 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5211 follows:</p>
5212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5213<ol>
5214 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5215
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5216 <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]5217 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5218
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5219 <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]5220 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5221
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5222 <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]5223 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5224
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5225 <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]5226 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5227
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5228 <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]5229 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5230
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5231 <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]5232 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5233
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5234 <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]5235
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5236 <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]5237 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5238
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5239 <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]5240 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5241
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5242 <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]5243 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5244
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5245 <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]5246 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5247
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5248 <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]5249 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5250
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5251 <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]5252 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5253
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5254 <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]5255
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5256 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5257</ol>
5258
5259<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5260<pre>
5261 &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]5262 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5263 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5264 &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]5265</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5266
5267<p>Note that the code generator does not yet support vector types with
5268 the <tt>fcmp</tt> instruction.</p>
5269
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5270</div>
5271
5272<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]5273<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5274 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5275</div>
5276
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5277<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5279<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5280<pre>
5281 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5282</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5283
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5284<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5285<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5286 SSA graph representing the function.</p>
5287
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5288<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5289<p>The type of the incoming values is specified with the first type field. After
5290 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5291 one pair for each predecessor basic block of the current block. Only values
5292 of <a href="#t_firstclass">first class</a> type may be used as the value
5293 arguments to the PHI node. Only labels may be used as the label
5294 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5295
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5296<p>There must be no non-phi instructions between the start of a basic block and
5297 the PHI instructions: i.e. PHI instructions must be first in a basic
5298 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5299
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5300<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5301 occur on the edge from the corresponding predecessor block to the current
5302 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5303 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]5304
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5305<h5>Semantics:</h5>
5306<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5307 specified by the pair corresponding to the predecessor basic block that
5308 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5309
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5310<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5311<pre>
5312Loop: ; Infinite loop that counts from 0 on up...
5313 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5314 %nextindvar = add i32 %indvar, 1
5315 br label %Loop
5316</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5317
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5318</div>
5319
5320<!-- _______________________________________________________________________ -->
5321<div class="doc_subsubsection">
5322 <a name="i_select">'<tt>select</tt>' Instruction</a>
5323</div>
5324
5325<div class="doc_text">
5326
5327<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5328<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]5329 &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>
5330
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5331 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5332</pre>
5333
5334<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5335<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5336 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5337
5338
5339<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5340<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5341 values indicating the condition, and two values of the
5342 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5343 vectors and the condition is a scalar, then entire vectors are selected, not
5344 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5345
5346<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5347<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5348 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5349
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5350<p>If the condition is a vector of i1, then the value arguments must be vectors
5351 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5352
5353<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5354<pre>
5355 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
5356</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5357
5358<p>Note that the code generator does not yet support conditions
5359 with vector type.</p>
5360
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5361</div>
5362
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5363<!-- _______________________________________________________________________ -->
5364<div class="doc_subsubsection">
5365 <a name="i_call">'<tt>call</tt>' Instruction</a>
5366</div>
5367
5368<div class="doc_text">
5369
5370<h5>Syntax:</h5>
5371<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]5372 &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]5373</pre>
5374
5375<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5376<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
5377
5378<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5379<p>This instruction requires several arguments:</p>
5380
5381<ol>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5382 <li>The optional "tail" marker indicates that the callee function does not
5383 access any allocas or varargs in the caller. Note that calls may be
5384 marked "tail" even if they do not occur before
5385 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5386 present, the function call is eligible for tail call optimization,
5387 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengcc7495c2010-03-08 21:05:02 +0000[diff] [blame]5388 optimized into a jump</a>. The code generator may optimize calls marked
5389 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5390 sibling call optimization</a> when the caller and callee have
5391 matching signatures, or 2) forced tail call optimization when the
5392 following extra requirements are met:
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5393 <ul>
5394 <li>Caller and callee both have the calling
5395 convention <tt>fastcc</tt>.</li>
5396 <li>The call is in tail position (ret immediately follows call and ret
5397 uses value of call or is void).</li>
5398 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman1be84f02010-03-02 01:08:11 +0000[diff] [blame]5399 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5400 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5401 constraints are met.</a></li>
5402 </ul>
5403 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5404
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5405 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5406 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5407 defaults to using C calling conventions. The calling convention of the
5408 call must match the calling convention of the target function, or else the
5409 behavior is undefined.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5410
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5411 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5412 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5413 '<tt>inreg</tt>' attributes are valid here.</li>
5414
5415 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5416 type of the return value. Functions that return no value are marked
5417 <tt><a href="#t_void">void</a></tt>.</li>
5418
5419 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5420 being invoked. The argument types must match the types implied by this
5421 signature. This type can be omitted if the function is not varargs and if
5422 the function type does not return a pointer to a function.</li>
5423
5424 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5425 be invoked. In most cases, this is a direct function invocation, but
5426 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5427 to function value.</li>
5428
5429 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]5430 signature argument types and parameter attributes. All arguments must be
5431 of <a href="#t_firstclass">first class</a> type. If the function
5432 signature indicates the function accepts a variable number of arguments,
5433 the extra arguments can be specified.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5434
5435 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5436 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5437 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5438</ol>
5439
5440<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5441<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5442 a specified function, with its incoming arguments bound to the specified
5443 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5444 function, control flow continues with the instruction after the function
5445 call, and the return value of the function is bound to the result
5446 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5447
5448<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5449<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5450 %retval = call i32 @test(i32 %argc)
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]5451 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5452 %X = tail call i32 @foo() <i>; yields i32</i>
5453 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5454 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5455
5456 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5457 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5458 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5459 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5460 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5461 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5462</pre>
5463
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5464<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5465standard C99 library as being the C99 library functions, and may perform
5466optimizations or generate code for them under that assumption. This is
5467something we'd like to change in the future to provide better support for
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5468freestanding environments and non-C-based languages.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5469
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5470</div>
5471
5472<!-- _______________________________________________________________________ -->
5473<div class="doc_subsubsection">
5474 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5475</div>
5476
5477<div class="doc_text">
5478
5479<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5480<pre>
5481 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5482</pre>
5483
5484<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5485<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5486 the "variable argument" area of a function call. It is used to implement the
5487 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5488
5489<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5490<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5491 argument. It returns a value of the specified argument type and increments
5492 the <tt>va_list</tt> to point to the next argument. The actual type
5493 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5494
5495<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5496<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5497 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5498 to the next argument. For more information, see the variable argument
5499 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5500
5501<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]5502 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5503 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5504
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5505<p><tt>va_arg</tt> is an LLVM instruction instead of
5506 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5507 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5508
5509<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5510<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5511
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5512<p>Note that the code generator does not yet fully support va_arg on many
5513 targets. Also, it does not currently support va_arg with aggregate types on
5514 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5515
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5516</div>
5517
5518<!-- *********************************************************************** -->
5519<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5520<!-- *********************************************************************** -->
5521
5522<div class="doc_text">
5523
5524<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5525 well known names and semantics and are required to follow certain
5526 restrictions. Overall, these intrinsics represent an extension mechanism for
5527 the LLVM language that does not require changing all of the transformations
5528 in LLVM when adding to the language (or the bitcode reader/writer, the
5529 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5530
5531<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5532 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5533 begin with this prefix. Intrinsic functions must always be external
5534 functions: you cannot define the body of intrinsic functions. Intrinsic
5535 functions may only be used in call or invoke instructions: it is illegal to
5536 take the address of an intrinsic function. Additionally, because intrinsic
5537 functions are part of the LLVM language, it is required if any are added that
5538 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5539
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5540<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5541 family of functions that perform the same operation but on different data
5542 types. Because LLVM can represent over 8 million different integer types,
5543 overloading is used commonly to allow an intrinsic function to operate on any
5544 integer type. One or more of the argument types or the result type can be
5545 overloaded to accept any integer type. Argument types may also be defined as
5546 exactly matching a previous argument's type or the result type. This allows
5547 an intrinsic function which accepts multiple arguments, but needs all of them
5548 to be of the same type, to only be overloaded with respect to a single
5549 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5550
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5551<p>Overloaded intrinsics will have the names of its overloaded argument types
5552 encoded into its function name, each preceded by a period. Only those types
5553 which are overloaded result in a name suffix. Arguments whose type is matched
5554 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5555 can take an integer of any width and returns an integer of exactly the same
5556 integer width. This leads to a family of functions such as
5557 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5558 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5559 suffix is required. Because the argument's type is matched against the return
5560 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5561
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5562<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5563 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5564
5565</div>
5566
5567<!-- ======================================================================= -->
5568<div class="doc_subsection">
5569 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5570</div>
5571
5572<div class="doc_text">
5573
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5574<p>Variable argument support is defined in LLVM with
5575 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5576 intrinsic functions. These functions are related to the similarly named
5577 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5578
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5579<p>All of these functions operate on arguments that use a target-specific value
5580 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5581 not define what this type is, so all transformations should be prepared to
5582 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5583
5584<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]5585 instruction and the variable argument handling intrinsic functions are
5586 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5587
5588<div class="doc_code">
5589<pre>
5590define i32 @test(i32 %X, ...) {
5591 ; Initialize variable argument processing
5592 %ap = alloca i8*
5593 %ap2 = bitcast i8** %ap to i8*
5594 call void @llvm.va_start(i8* %ap2)
5595
5596 ; Read a single integer argument
5597 %tmp = va_arg i8** %ap, i32
5598
5599 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5600 %aq = alloca i8*
5601 %aq2 = bitcast i8** %aq to i8*
5602 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5603 call void @llvm.va_end(i8* %aq2)
5604
5605 ; Stop processing of arguments.
5606 call void @llvm.va_end(i8* %ap2)
5607 ret i32 %tmp
5608}
5609
5610declare void @llvm.va_start(i8*)
5611declare void @llvm.va_copy(i8*, i8*)
5612declare void @llvm.va_end(i8*)
5613</pre>
5614</div>
5615
5616</div>
5617
5618<!-- _______________________________________________________________________ -->
5619<div class="doc_subsubsection">
5620 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5621</div>
5622
5623
5624<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5625
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5626<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5627<pre>
5628 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5629</pre>
5630
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5631<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5632<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5633 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]5634
5635<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5636<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]5637
5638<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5639<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]5640 macro available in C. In a target-dependent way, it initializes
5641 the <tt>va_list</tt> element to which the argument points, so that the next
5642 call to <tt>va_arg</tt> will produce the first variable argument passed to
5643 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5644 need to know the last argument of the function as the compiler can figure
5645 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5646
5647</div>
5648
5649<!-- _______________________________________________________________________ -->
5650<div class="doc_subsubsection">
5651 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5652</div>
5653
5654<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5655
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5656<h5>Syntax:</h5>
5657<pre>
5658 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5659</pre>
5660
5661<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5662<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5663 which has been initialized previously
5664 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5665 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5666
5667<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5668<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5669
5670<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5671<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]5672 macro available in C. In a target-dependent way, it destroys
5673 the <tt>va_list</tt> element to which the argument points. Calls
5674 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5675 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5676 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5677
5678</div>
5679
5680<!-- _______________________________________________________________________ -->
5681<div class="doc_subsubsection">
5682 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5683</div>
5684
5685<div class="doc_text">
5686
5687<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5688<pre>
5689 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5690</pre>
5691
5692<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5693<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5694 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5695
5696<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5697<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]5698 The second argument is a pointer to a <tt>va_list</tt> element to copy
5699 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5700
5701<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5702<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]5703 macro available in C. In a target-dependent way, it copies the
5704 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5705 element. This intrinsic is necessary because
5706 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5707 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5708
5709</div>
5710
5711<!-- ======================================================================= -->
5712<div class="doc_subsection">
5713 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5714</div>
5715
5716<div class="doc_text">
5717
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5718<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5719Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5720intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5721roots on the stack</a>, as well as garbage collector implementations that
5722require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5723barriers. Front-ends for type-safe garbage collected languages should generate
5724these intrinsics to make use of the LLVM garbage collectors. For more details,
5725see <a href="GarbageCollection.html">Accurate Garbage Collection with
5726LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5727
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5728<p>The garbage collection intrinsics only operate on objects in the generic
5729 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5730
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5731</div>
5732
5733<!-- _______________________________________________________________________ -->
5734<div class="doc_subsubsection">
5735 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5736</div>
5737
5738<div class="doc_text">
5739
5740<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5741<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5742 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5743</pre>
5744
5745<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5746<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]5747 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5748
5749<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5750<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5751 root pointer. The second pointer (which must be either a constant or a
5752 global value address) contains the meta-data to be associated with the
5753 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5754
5755<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5756<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]5757 location. At compile-time, the code generator generates information to allow
5758 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5759 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5760 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5761
5762</div>
5763
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5764<!-- _______________________________________________________________________ -->
5765<div class="doc_subsubsection">
5766 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5767</div>
5768
5769<div class="doc_text">
5770
5771<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5772<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5773 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5774</pre>
5775
5776<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5777<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5778 locations, allowing garbage collector implementations that require read
5779 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5780
5781<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5782<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]5783 allocated from the garbage collector. The first object is a pointer to the
5784 start of the referenced object, if needed by the language runtime (otherwise
5785 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5786
5787<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5788<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5789 instruction, but may be replaced with substantially more complex code by the
5790 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5791 may only be used in a function which <a href="#gc">specifies a GC
5792 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5793
5794</div>
5795
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5796<!-- _______________________________________________________________________ -->
5797<div class="doc_subsubsection">
5798 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5799</div>
5800
5801<div class="doc_text">
5802
5803<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5804<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5805 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5806</pre>
5807
5808<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5809<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5810 locations, allowing garbage collector implementations that require write
5811 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5812
5813<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5814<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]5815 object to store it to, and the third is the address of the field of Obj to
5816 store to. If the runtime does not require a pointer to the object, Obj may
5817 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5818
5819<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5820<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5821 instruction, but may be replaced with substantially more complex code by the
5822 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5823 may only be used in a function which <a href="#gc">specifies a GC
5824 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5825
5826</div>
5827
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5828<!-- ======================================================================= -->
5829<div class="doc_subsection">
5830 <a name="int_codegen">Code Generator Intrinsics</a>
5831</div>
5832
5833<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5834
5835<p>These intrinsics are provided by LLVM to expose special features that may
5836 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5837
5838</div>
5839
5840<!-- _______________________________________________________________________ -->
5841<div class="doc_subsubsection">
5842 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5843</div>
5844
5845<div class="doc_text">
5846
5847<h5>Syntax:</h5>
5848<pre>
5849 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5850</pre>
5851
5852<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5853<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5854 target-specific value indicating the return address of the current function
5855 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5856
5857<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5858<p>The argument to this intrinsic indicates which function to return the address
5859 for. Zero indicates the calling function, one indicates its caller, etc.
5860 The argument is <b>required</b> to be a constant integer value.</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>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5864 indicating the return address of the specified call frame, or zero if it
5865 cannot be identified. The value returned by this intrinsic is likely to be
5866 incorrect or 0 for arguments other than zero, so it should only be used for
5867 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5868
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5869<p>Note that calling this intrinsic does not prevent function inlining or other
5870 aggressive transformations, so the value returned may not be that of the
5871 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5872
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5873</div>
5874
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5875<!-- _______________________________________________________________________ -->
5876<div class="doc_subsubsection">
5877 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5878</div>
5879
5880<div class="doc_text">
5881
5882<h5>Syntax:</h5>
5883<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]5884 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5885</pre>
5886
5887<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5888<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5889 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5890
5891<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5892<p>The argument to this intrinsic indicates which function to return the frame
5893 pointer for. Zero indicates the calling function, one indicates its caller,
5894 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5895
5896<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5897<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5898 indicating the frame address of the specified call frame, or zero if it
5899 cannot be identified. The value returned by this intrinsic is likely to be
5900 incorrect or 0 for arguments other than zero, so it should only be used for
5901 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5902
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5903<p>Note that calling this intrinsic does not prevent function inlining or other
5904 aggressive transformations, so the value returned may not be that of the
5905 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5906
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5907</div>
5908
5909<!-- _______________________________________________________________________ -->
5910<div class="doc_subsubsection">
5911 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5912</div>
5913
5914<div class="doc_text">
5915
5916<h5>Syntax:</h5>
5917<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]5918 declare i8* @llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5919</pre>
5920
5921<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5922<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5923 of the function stack, for use
5924 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5925 useful for implementing language features like scoped automatic variable
5926 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5927
5928<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5929<p>This intrinsic returns a opaque pointer value that can be passed
5930 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5931 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5932 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5933 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5934 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5935 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5936
5937</div>
5938
5939<!-- _______________________________________________________________________ -->
5940<div class="doc_subsubsection">
5941 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5942</div>
5943
5944<div class="doc_text">
5945
5946<h5>Syntax:</h5>
5947<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]5948 declare void @llvm.stackrestore(i8* %ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5949</pre>
5950
5951<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5952<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5953 the function stack to the state it was in when the
5954 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5955 executed. This is useful for implementing language features like scoped
5956 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5957
5958<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5959<p>See the description
5960 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5961
5962</div>
5963
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5964<!-- _______________________________________________________________________ -->
5965<div class="doc_subsubsection">
5966 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5967</div>
5968
5969<div class="doc_text">
5970
5971<h5>Syntax:</h5>
5972<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5973 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]5974</pre>
5975
5976<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5977<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5978 insert a prefetch instruction if supported; otherwise, it is a noop.
5979 Prefetches have no effect on the behavior of the program but can change its
5980 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5981
5982<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5983<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5984 specifier determining if the fetch should be for a read (0) or write (1),
5985 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5986 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5987 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5988
5989<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5990<p>This intrinsic does not modify the behavior of the program. In particular,
5991 prefetches cannot trap and do not produce a value. On targets that support
5992 this intrinsic, the prefetch can provide hints to the processor cache for
5993 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5994
5995</div>
5996
5997<!-- _______________________________________________________________________ -->
5998<div class="doc_subsubsection">
5999 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
6000</div>
6001
6002<div class="doc_text">
6003
6004<h5>Syntax:</h5>
6005<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]6006 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6007</pre>
6008
6009<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6010<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6011 Counter (PC) in a region of code to simulators and other tools. The method
6012 is target specific, but it is expected that the marker will use exported
6013 symbols to transmit the PC of the marker. The marker makes no guarantees
6014 that it will remain with any specific instruction after optimizations. It is
6015 possible that the presence of a marker will inhibit optimizations. The
6016 intended use is to be inserted after optimizations to allow correlations of
6017 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6018
6019<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6020<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6021
6022<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6023<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6024 not support this intrinsic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6025
6026</div>
6027
6028<!-- _______________________________________________________________________ -->
6029<div class="doc_subsubsection">
6030 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
6031</div>
6032
6033<div class="doc_text">
6034
6035<h5>Syntax:</h5>
6036<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]6037 declare i64 @llvm.readcyclecounter()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6038</pre>
6039
6040<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6041<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6042 counter register (or similar low latency, high accuracy clocks) on those
6043 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6044 should map to RPCC. As the backing counters overflow quickly (on the order
6045 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6046
6047<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6048<p>When directly supported, reading the cycle counter should not modify any
6049 memory. Implementations are allowed to either return a application specific
6050 value or a system wide value. On backends without support, this is lowered
6051 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6052
6053</div>
6054
6055<!-- ======================================================================= -->
6056<div class="doc_subsection">
6057 <a name="int_libc">Standard C Library Intrinsics</a>
6058</div>
6059
6060<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6061
6062<p>LLVM provides intrinsics for a few important standard C library functions.
6063 These intrinsics allow source-language front-ends to pass information about
6064 the alignment of the pointer arguments to the code generator, providing
6065 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6066
6067</div>
6068
6069<!-- _______________________________________________________________________ -->
6070<div class="doc_subsubsection">
6071 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
6072</div>
6073
6074<div class="doc_text">
6075
6076<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6077<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]6078 integer bit width and for different address spaces. Not all targets support
6079 all bit widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6080
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6081<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6082 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]6083 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6084 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]6085 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6086</pre>
6087
6088<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6089<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6090 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6091
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6092<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6093 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6094 and the pointers can be in specified address spaces.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6095
6096<h5>Arguments:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6097
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6098<p>The first argument is a pointer to the destination, the second is a pointer
6099 to the source. The third argument is an integer argument specifying the
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6100 number of bytes to copy, the fourth argument is the alignment of the
6101 source and destination locations, and the fifth is a boolean indicating a
6102 volatile access.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6103
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6104<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]6105 then the caller guarantees that both the source and destination pointers are
6106 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6107
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]6108<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6109 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6110 The detailed access behavior is not very cleanly specified and it is unwise
6111 to depend on it.</p>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6112
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6113<h5>Semantics:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6114
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6115<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6116 source location to the destination location, which are not allowed to
6117 overlap. It copies "len" bytes of memory over. If the argument is known to
6118 be aligned to some boundary, this can be specified as the fourth argument,
6119 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6120
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6121</div>
6122
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6123<!-- _______________________________________________________________________ -->
6124<div class="doc_subsubsection">
6125 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
6126</div>
6127
6128<div class="doc_text">
6129
6130<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]6131<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]6132 width and for different address space. Not all targets support all bit
6133 widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6134
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6135<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6136 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]6137 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6138 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]6139 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6140</pre>
6141
6142<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6143<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6144 source location to the destination location. It is similar to the
6145 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6146 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6147
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6148<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6149 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6150 and the pointers can be in specified address spaces.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6151
6152<h5>Arguments:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6153
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6154<p>The first argument is a pointer to the destination, the second is a pointer
6155 to the source. The third argument is an integer argument specifying the
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6156 number of bytes to copy, the fourth argument is the alignment of the
6157 source and destination locations, and the fifth is a boolean indicating a
6158 volatile access.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6159
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6160<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]6161 then the caller guarantees that the source and destination pointers are
6162 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6163
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]6164<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6165 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6166 The detailed access behavior is not very cleanly specified and it is unwise
6167 to depend on it.</p>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6168
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6169<h5>Semantics:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6170
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6171<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6172 source location to the destination location, which may overlap. It copies
6173 "len" bytes of memory over. If the argument is known to be aligned to some
6174 boundary, this can be specified as the fourth argument, otherwise it should
6175 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6176
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6177</div>
6178
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6179<!-- _______________________________________________________________________ -->
6180<div class="doc_subsubsection">
6181 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
6182</div>
6183
6184<div class="doc_text">
6185
6186<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]6187<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]6188 width and for different address spaces. Not all targets support all bit
6189 widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6190
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6191<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6192 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerc0dfafe2010-04-08 00:54:34 +0000[diff] [blame]6193 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6194 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerc0dfafe2010-04-08 00:54:34 +0000[diff] [blame]6195 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6196</pre>
6197
6198<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6199<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6200 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6201
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6202<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6203 intrinsic does not return a value, takes extra alignment/volatile arguments,
6204 and the destination can be in an arbitrary address space.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6205
6206<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6207<p>The first argument is a pointer to the destination to fill, the second is the
6208 byte value to fill it with, the third argument is an integer argument
6209 specifying the number of bytes to fill, and the fourth argument is the known
6210 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6211
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6212<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]6213 then the caller guarantees that the destination pointer is aligned to that
6214 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6215
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]6216<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6217 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6218 The detailed access behavior is not very cleanly specified and it is unwise
6219 to depend on it.</p>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6220
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6221<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6222<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6223 at the destination location. If the argument is known to be aligned to some
6224 boundary, this can be specified as the fourth argument, otherwise it should
6225 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6226
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6227</div>
6228
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6229<!-- _______________________________________________________________________ -->
6230<div class="doc_subsubsection">
6231 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
6232</div>
6233
6234<div class="doc_text">
6235
6236<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6237<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6238 floating point or vector of floating point type. Not all targets support all
6239 types however.</p>
6240
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6241<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]6242 declare float @llvm.sqrt.f32(float %Val)
6243 declare double @llvm.sqrt.f64(double %Val)
6244 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6245 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6246 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6247</pre>
6248
6249<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6250<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6251 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6252 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6253 behavior for negative numbers other than -0.0 (which allows for better
6254 optimization, because there is no need to worry about errno being
6255 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]6256
6257<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6258<p>The argument and return value are floating point numbers of the same
6259 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6260
6261<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6262<p>This function returns the sqrt of the specified operand if it is a
6263 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6264
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6265</div>
6266
6267<!-- _______________________________________________________________________ -->
6268<div class="doc_subsubsection">
6269 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
6270</div>
6271
6272<div class="doc_text">
6273
6274<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6275<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6276 floating point or vector of floating point type. Not all targets support all
6277 types however.</p>
6278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6279<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]6280 declare float @llvm.powi.f32(float %Val, i32 %power)
6281 declare double @llvm.powi.f64(double %Val, i32 %power)
6282 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6283 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6284 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6285</pre>
6286
6287<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6288<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6289 specified (positive or negative) power. The order of evaluation of
6290 multiplications is not defined. When a vector of floating point type is
6291 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6292
6293<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6294<p>The second argument is an integer power, and the first is a value to raise to
6295 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6296
6297<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6298<p>This function returns the first value raised to the second power with an
6299 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6300
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6301</div>
6302
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6303<!-- _______________________________________________________________________ -->
6304<div class="doc_subsubsection">
6305 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6306</div>
6307
6308<div class="doc_text">
6309
6310<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6311<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6312 floating point or vector of floating point type. Not all targets support all
6313 types however.</p>
6314
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6315<pre>
6316 declare float @llvm.sin.f32(float %Val)
6317 declare double @llvm.sin.f64(double %Val)
6318 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6319 declare fp128 @llvm.sin.f128(fp128 %Val)
6320 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6321</pre>
6322
6323<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6324<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6325
6326<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6327<p>The argument and return value are floating point numbers of the same
6328 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6329
6330<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6331<p>This function returns the sine of the specified operand, returning the same
6332 values as the libm <tt>sin</tt> functions would, and handles error conditions
6333 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6334
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6335</div>
6336
6337<!-- _______________________________________________________________________ -->
6338<div class="doc_subsubsection">
6339 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6340</div>
6341
6342<div class="doc_text">
6343
6344<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6345<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6346 floating point or vector of floating point type. Not all targets support all
6347 types however.</p>
6348
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6349<pre>
6350 declare float @llvm.cos.f32(float %Val)
6351 declare double @llvm.cos.f64(double %Val)
6352 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6353 declare fp128 @llvm.cos.f128(fp128 %Val)
6354 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6355</pre>
6356
6357<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6358<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6359
6360<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6361<p>The argument and return value are floating point numbers of the same
6362 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6363
6364<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6365<p>This function returns the cosine of the specified operand, returning the same
6366 values as the libm <tt>cos</tt> functions would, and handles error conditions
6367 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6368
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6369</div>
6370
6371<!-- _______________________________________________________________________ -->
6372<div class="doc_subsubsection">
6373 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6374</div>
6375
6376<div class="doc_text">
6377
6378<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6379<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6380 floating point or vector of floating point type. Not all targets support all
6381 types however.</p>
6382
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6383<pre>
6384 declare float @llvm.pow.f32(float %Val, float %Power)
6385 declare double @llvm.pow.f64(double %Val, double %Power)
6386 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6387 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6388 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6389</pre>
6390
6391<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6392<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6393 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6394
6395<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6396<p>The second argument is a floating point power, and the first is a value to
6397 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6398
6399<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6400<p>This function returns the first value raised to the second power, returning
6401 the same values as the libm <tt>pow</tt> functions would, and handles error
6402 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6403
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6404</div>
6405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6406<!-- ======================================================================= -->
6407<div class="doc_subsection">
6408 <a name="int_manip">Bit Manipulation Intrinsics</a>
6409</div>
6410
6411<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6412
6413<p>LLVM provides intrinsics for a few important bit manipulation operations.
6414 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6415
6416</div>
6417
6418<!-- _______________________________________________________________________ -->
6419<div class="doc_subsubsection">
6420 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
6421</div>
6422
6423<div class="doc_text">
6424
6425<h5>Syntax:</h5>
6426<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6427 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6428
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6429<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6430 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6431 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6432 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6433</pre>
6434
6435<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6436<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6437 values with an even number of bytes (positive multiple of 16 bits). These
6438 are useful for performing operations on data that is not in the target's
6439 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6440
6441<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6442<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6443 and low byte of the input i16 swapped. Similarly,
6444 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6445 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6446 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6447 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6448 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6449 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6450
6451</div>
6452
6453<!-- _______________________________________________________________________ -->
6454<div class="doc_subsubsection">
6455 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6456</div>
6457
6458<div class="doc_text">
6459
6460<h5>Syntax:</h5>
6461<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]6462 width. Not all targets support all bit widths however.</p>
6463
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6464<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6465 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6466 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6467 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6468 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6469 declare i256 @llvm.ctpop.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.ctpop</tt>' family of intrinsics counts the number of bits set
6474 in a value.</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.ctpop</tt>' intrinsic counts the 1's in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6482
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6483</div>
6484
6485<!-- _______________________________________________________________________ -->
6486<div class="doc_subsubsection">
6487 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6488</div>
6489
6490<div class="doc_text">
6491
6492<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6493<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6494 integer bit width. Not all targets support all bit widths however.</p>
6495
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6496<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6497 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6498 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6499 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6500 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6501 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6502</pre>
6503
6504<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6505<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6506 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6507
6508<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6509<p>The only argument is the value to be counted. The argument may be of any
6510 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6511
6512<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6513<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6514 zeros in a variable. If the src == 0 then the result is the size in bits of
6515 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6516
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6517</div>
6518
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6519<!-- _______________________________________________________________________ -->
6520<div class="doc_subsubsection">
6521 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6522</div>
6523
6524<div class="doc_text">
6525
6526<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6527<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6528 integer bit width. Not all targets support all bit widths however.</p>
6529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6530<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6531 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6532 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6533 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6534 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6535 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6536</pre>
6537
6538<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6539<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6540 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6541
6542<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6543<p>The only argument is the value to be counted. The argument may be of any
6544 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6545
6546<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6547<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6548 zeros in a variable. If the src == 0 then the result is the size in bits of
6549 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6550
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6551</div>
6552
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6553<!-- ======================================================================= -->
6554<div class="doc_subsection">
6555 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6556</div>
6557
6558<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6559
6560<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6561
6562</div>
6563
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6564<!-- _______________________________________________________________________ -->
6565<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6566 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6567</div>
6568
6569<div class="doc_text">
6570
6571<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6572<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]6573 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6574
6575<pre>
6576 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6577 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6578 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6579</pre>
6580
6581<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6582<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6583 a signed addition of the two arguments, and indicate whether an overflow
6584 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6585
6586<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6587<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]6588 be of integer types of any bit width, but they must have the same bit
6589 width. The second element of the result structure must be of
6590 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6591 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6592
6593<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6594<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6595 a signed addition of the two variables. They return a structure &mdash; the
6596 first element of which is the signed summation, and the second element of
6597 which is a bit specifying if the signed summation resulted in an
6598 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6599
6600<h5>Examples:</h5>
6601<pre>
6602 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6603 %sum = extractvalue {i32, i1} %res, 0
6604 %obit = extractvalue {i32, i1} %res, 1
6605 br i1 %obit, label %overflow, label %normal
6606</pre>
6607
6608</div>
6609
6610<!-- _______________________________________________________________________ -->
6611<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6612 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6613</div>
6614
6615<div class="doc_text">
6616
6617<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6618<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]6619 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6620
6621<pre>
6622 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6623 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6624 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6625</pre>
6626
6627<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6628<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6629 an unsigned addition of the two arguments, and indicate whether a carry
6630 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6631
6632<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6633<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]6634 be of integer types of any bit width, but they must have the same bit
6635 width. The second element of the result structure must be of
6636 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6637 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6638
6639<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6640<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6641 an unsigned addition of the two arguments. They return a structure &mdash;
6642 the first element of which is the sum, and the second element of which is a
6643 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6644
6645<h5>Examples:</h5>
6646<pre>
6647 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6648 %sum = extractvalue {i32, i1} %res, 0
6649 %obit = extractvalue {i32, i1} %res, 1
6650 br i1 %obit, label %carry, label %normal
6651</pre>
6652
6653</div>
6654
6655<!-- _______________________________________________________________________ -->
6656<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6657 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6658</div>
6659
6660<div class="doc_text">
6661
6662<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6663<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]6664 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6665
6666<pre>
6667 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6668 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6669 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6670</pre>
6671
6672<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6673<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6674 a signed subtraction of the two arguments, and indicate whether an overflow
6675 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6676
6677<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6678<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]6679 be of integer types of any bit width, but they must have the same bit
6680 width. The second element of the result structure must be of
6681 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6682 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6683
6684<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6685<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6686 a signed subtraction of the two arguments. They return a structure &mdash;
6687 the first element of which is the subtraction, and the second element of
6688 which is a bit specifying if the signed subtraction resulted in an
6689 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6690
6691<h5>Examples:</h5>
6692<pre>
6693 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6694 %sum = extractvalue {i32, i1} %res, 0
6695 %obit = extractvalue {i32, i1} %res, 1
6696 br i1 %obit, label %overflow, label %normal
6697</pre>
6698
6699</div>
6700
6701<!-- _______________________________________________________________________ -->
6702<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6703 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6704</div>
6705
6706<div class="doc_text">
6707
6708<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6709<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]6710 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6711
6712<pre>
6713 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6714 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6715 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6716</pre>
6717
6718<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6719<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6720 an unsigned subtraction of the two arguments, and indicate whether an
6721 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6722
6723<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6724<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]6725 be of integer types of any bit width, but they must have the same bit
6726 width. The second element of the result structure must be of
6727 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6728 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6729
6730<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6731<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6732 an unsigned subtraction of the two arguments. They return a structure &mdash;
6733 the first element of which is the subtraction, and the second element of
6734 which is a bit specifying if the unsigned subtraction resulted in an
6735 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6736
6737<h5>Examples:</h5>
6738<pre>
6739 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6740 %sum = extractvalue {i32, i1} %res, 0
6741 %obit = extractvalue {i32, i1} %res, 1
6742 br i1 %obit, label %overflow, label %normal
6743</pre>
6744
6745</div>
6746
6747<!-- _______________________________________________________________________ -->
6748<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6749 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6750</div>
6751
6752<div class="doc_text">
6753
6754<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6755<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]6756 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6757
6758<pre>
6759 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6760 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6761 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6762</pre>
6763
6764<h5>Overview:</h5>
6765
6766<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6767 a signed multiplication of the two arguments, and indicate whether an
6768 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6769
6770<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6771<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]6772 be of integer types of any bit width, but they must have the same bit
6773 width. The second element of the result structure must be of
6774 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6775 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6776
6777<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6778<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6779 a signed multiplication of the two arguments. They return a structure &mdash;
6780 the first element of which is the multiplication, and the second element of
6781 which is a bit specifying if the signed multiplication resulted in an
6782 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6783
6784<h5>Examples:</h5>
6785<pre>
6786 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6787 %sum = extractvalue {i32, i1} %res, 0
6788 %obit = extractvalue {i32, i1} %res, 1
6789 br i1 %obit, label %overflow, label %normal
6790</pre>
6791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6792</div>
6793
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6794<!-- _______________________________________________________________________ -->
6795<div class="doc_subsubsection">
6796 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6797</div>
6798
6799<div class="doc_text">
6800
6801<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6802<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]6803 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6804
6805<pre>
6806 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6807 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6808 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6809</pre>
6810
6811<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6812<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6813 a unsigned multiplication of the two arguments, and indicate whether an
6814 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6815
6816<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6817<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]6818 be of integer types of any bit width, but they must have the same bit
6819 width. The second element of the result structure must be of
6820 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6821 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6822
6823<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6824<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6825 an unsigned multiplication of the two arguments. They return a structure
6826 &mdash; the first element of which is the multiplication, and the second
6827 element of which is a bit specifying if the unsigned multiplication resulted
6828 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6829
6830<h5>Examples:</h5>
6831<pre>
6832 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6833 %sum = extractvalue {i32, i1} %res, 0
6834 %obit = extractvalue {i32, i1} %res, 1
6835 br i1 %obit, label %overflow, label %normal
6836</pre>
6837
6838</div>
6839
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6840<!-- ======================================================================= -->
6841<div class="doc_subsection">
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6842 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6843</div>
6844
6845<div class="doc_text">
6846
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6847<p>Half precision floating point is a storage-only format. This means that it is
6848 a dense encoding (in memory) but does not support computation in the
6849 format.</p>
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6850
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6851<p>This means that code must first load the half-precision floating point
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6852 value as an i16, then convert it to float with <a
6853 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6854 Computation can then be performed on the float value (including extending to
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6855 double etc). To store the value back to memory, it is first converted to
6856 float if needed, then converted to i16 with
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6857 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6858 storing as an i16 value.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6859</div>
6860
6861<!-- _______________________________________________________________________ -->
6862<div class="doc_subsubsection">
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6863 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6864</div>
6865
6866<div class="doc_text">
6867
6868<h5>Syntax:</h5>
6869<pre>
6870 declare i16 @llvm.convert.to.fp16(f32 %a)
6871</pre>
6872
6873<h5>Overview:</h5>
6874<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6875 a conversion from single precision floating point format to half precision
6876 floating point format.</p>
6877
6878<h5>Arguments:</h5>
6879<p>The intrinsic function contains single argument - the value to be
6880 converted.</p>
6881
6882<h5>Semantics:</h5>
6883<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6884 a conversion from single precision floating point format to half precision
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6885 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6886 contains the converted number.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6887
6888<h5>Examples:</h5>
6889<pre>
6890 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6891 store i16 %res, i16* @x, align 2
6892</pre>
6893
6894</div>
6895
6896<!-- _______________________________________________________________________ -->
6897<div class="doc_subsubsection">
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6898 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6899</div>
6900
6901<div class="doc_text">
6902
6903<h5>Syntax:</h5>
6904<pre>
6905 declare f32 @llvm.convert.from.fp16(i16 %a)
6906</pre>
6907
6908<h5>Overview:</h5>
6909<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6910 a conversion from half precision floating point format to single precision
6911 floating point format.</p>
6912
6913<h5>Arguments:</h5>
6914<p>The intrinsic function contains single argument - the value to be
6915 converted.</p>
6916
6917<h5>Semantics:</h5>
6918<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6919 conversion from half single precision floating point format to single
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6920 precision floating point format. The input half-float value is represented by
6921 an <tt>i16</tt> value.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6922
6923<h5>Examples:</h5>
6924<pre>
6925 %a = load i16* @x, align 2
6926 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6927</pre>
6928
6929</div>
6930
6931<!-- ======================================================================= -->
6932<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6933 <a name="int_debugger">Debugger Intrinsics</a>
6934</div>
6935
6936<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6937
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6938<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6939 prefix), are described in
6940 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6941 Level Debugging</a> document.</p>
6942
6943</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6944
6945<!-- ======================================================================= -->
6946<div class="doc_subsection">
6947 <a name="int_eh">Exception Handling Intrinsics</a>
6948</div>
6949
6950<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6951
6952<p>The LLVM exception handling intrinsics (which all start with
6953 <tt>llvm.eh.</tt> prefix), are described in
6954 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6955 Handling</a> document.</p>
6956
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6957</div>
6958
6959<!-- ======================================================================= -->
6960<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6961 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6962</div>
6963
6964<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6965
6966<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanbd2f9ba2010-07-02 23:18:08 +0000[diff] [blame]6967 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6968 The result is a callable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6969 function pointer lacking the nest parameter - the caller does not need to
6970 provide a value for it. Instead, the value to use is stored in advance in a
6971 "trampoline", a block of memory usually allocated on the stack, which also
6972 contains code to splice the nest value into the argument list. This is used
6973 to implement the GCC nested function address extension.</p>
6974
6975<p>For example, if the function is
6976 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6977 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6978 follows:</p>
6979
6980<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6981<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6982 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6983 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]6984 %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]6985 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6986</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6987</div>
6988
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]6989<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6990 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6991
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6992</div>
6993
6994<!-- _______________________________________________________________________ -->
6995<div class="doc_subsubsection">
6996 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6997</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6998
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6999<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7000
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]7001<h5>Syntax:</h5>
7002<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7003 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]7004</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7005
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]7006<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7007<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
7008 function pointer suitable for executing it.</p>
7009
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]7010<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7011<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7012 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7013 sufficiently aligned block of memory; this memory is written to by the
7014 intrinsic. Note that the size and the alignment are target-specific - LLVM
7015 currently provides no portable way of determining them, so a front-end that
7016 generates this intrinsic needs to have some target-specific knowledge.
7017 The <tt>func</tt> argument must hold a function bitcast to
7018 an <tt>i8*</tt>.</p>
7019
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]7020<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7021<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
7022 dependent code, turning it into a function. A pointer to this function is
7023 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
7024 function pointer type</a> before being called. The new function's signature
7025 is the same as that of <tt>func</tt> with any arguments marked with
7026 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
7027 is allowed, and it must be of pointer type. Calling the new function is
7028 equivalent to calling <tt>func</tt> with the same argument list, but
7029 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
7030 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
7031 by <tt>tramp</tt> is modified, then the effect of any later call to the
7032 returned function pointer is undefined.</p>
7033
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]7034</div>
7035
7036<!-- ======================================================================= -->
7037<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7038 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
7039</div>
7040
7041<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7042
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7043<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7044 hardware constructs for atomic operations and memory synchronization. This
7045 provides an interface to the hardware, not an interface to the programmer. It
7046 is aimed at a low enough level to allow any programming models or APIs
7047 (Application Programming Interfaces) which need atomic behaviors to map
7048 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7049 hardware provides a "universal IR" for source languages, it also provides a
7050 starting point for developing a "universal" atomic operation and
7051 synchronization IR.</p>
7052
7053<p>These do <em>not</em> form an API such as high-level threading libraries,
7054 software transaction memory systems, atomic primitives, and intrinsic
7055 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7056 application libraries. The hardware interface provided by LLVM should allow
7057 a clean implementation of all of these APIs and parallel programming models.
7058 No one model or paradigm should be selected above others unless the hardware
7059 itself ubiquitously does so.</p>
7060
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7061</div>
7062
7063<!-- _______________________________________________________________________ -->
7064<div class="doc_subsubsection">
7065 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
7066</div>
7067<div class="doc_text">
7068<h5>Syntax:</h5>
7069<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7070 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]7071</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7072
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7073<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7074<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7075 specific pairs of memory access types.</p>
7076
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7077<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7078<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7079 The first four arguments enables a specific barrier as listed below. The
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]7080 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7081 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7082
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7083<ul>
7084 <li><tt>ll</tt>: load-load barrier</li>
7085 <li><tt>ls</tt>: load-store barrier</li>
7086 <li><tt>sl</tt>: store-load barrier</li>
7087 <li><tt>ss</tt>: store-store barrier</li>
7088 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7089</ul>
7090
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7091<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7092<p>This intrinsic causes the system to enforce some ordering constraints upon
7093 the loads and stores of the program. This barrier does not
7094 indicate <em>when</em> any events will occur, it only enforces
7095 an <em>order</em> in which they occur. For any of the specified pairs of load
7096 and store operations (f.ex. load-load, or store-load), all of the first
7097 operations preceding the barrier will complete before any of the second
7098 operations succeeding the barrier begin. Specifically the semantics for each
7099 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7100
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7101<ul>
7102 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7103 after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7104 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7105 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7106 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7107 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7108 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7109 load after the barrier begins.</li>
7110</ul>
7111
7112<p>These semantics are applied with a logical "and" behavior when more than one
7113 is enabled in a single memory barrier intrinsic.</p>
7114
7115<p>Backends may implement stronger barriers than those requested when they do
7116 not support as fine grained a barrier as requested. Some architectures do
7117 not need all types of barriers and on such architectures, these become
7118 noops.</p>
7119
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7120<h5>Example:</h5>
7121<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7122%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7123%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7124 store i32 4, %ptr
7125
7126%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7127 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7128 <i>; guarantee the above finishes</i>
7129 store i32 8, %ptr <i>; before this begins</i>
7130</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7131
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7132</div>
7133
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7134<!-- _______________________________________________________________________ -->
7135<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7136 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7137</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7138
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7139<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7140
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7141<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7142<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7143 any integer bit width and for different address spaces. Not all targets
7144 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7145
7146<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7147 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7148 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7149 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7150 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]7151</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7152
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7153<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7154<p>This loads a value in memory and compares it to a given value. If they are
7155 equal, it stores a new value into the memory.</p>
7156
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7157<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7158<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7159 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7160 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7161 this integer type. While any bit width integer may be used, targets may only
7162 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7163
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7164<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7165<p>This entire intrinsic must be executed atomically. It first loads the value
7166 in memory pointed to by <tt>ptr</tt> and compares it with the
7167 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7168 memory. The loaded value is yielded in all cases. This provides the
7169 equivalent of an atomic compare-and-swap operation within the SSA
7170 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7171
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7172<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7173<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7174%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7175%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7176 store i32 4, %ptr
7177
7178%val1 = add i32 4, 4
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7179%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7180 <i>; yields {i32}:result1 = 4</i>
7181%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7182%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7183
7184%val2 = add i32 1, 1
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7185%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7186 <i>; yields {i32}:result2 = 8</i>
7187%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7188
7189%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7190</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7191
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7192</div>
7193
7194<!-- _______________________________________________________________________ -->
7195<div class="doc_subsubsection">
7196 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7197</div>
7198<div class="doc_text">
7199<h5>Syntax:</h5>
7200
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7201<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7202 integer bit width. Not all targets support all bit widths however.</p>
7203
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7204<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7205 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7206 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7207 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7208 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]7209</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7210
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7211<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7212<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7213 the value from memory. It then stores the value in <tt>val</tt> in the memory
7214 at <tt>ptr</tt>.</p>
7215
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7216<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7217<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7218 the <tt>val</tt> argument and the result must be integers of the same bit
7219 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7220 integer type. The targets may only lower integer representations they
7221 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7222
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7223<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7224<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7225 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7226 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7227
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7228<h5>Examples:</h5>
7229<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7230%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7231%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7232 store i32 4, %ptr
7233
7234%val1 = add i32 4, 4
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7235%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7236 <i>; yields {i32}:result1 = 4</i>
7237%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7238%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7239
7240%val2 = add i32 1, 1
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7241%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7242 <i>; yields {i32}:result2 = 8</i>
7243
7244%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7245%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7246</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7247
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7248</div>
7249
7250<!-- _______________________________________________________________________ -->
7251<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7252 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7253
7254</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7255
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7256<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7257
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7258<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7259<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7260 any integer bit width. Not all targets support all bit widths however.</p>
7261
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7262<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7263 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7264 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7265 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7266 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]7267</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7268
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7269<h5>Overview:</h5>
7270<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7271 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7272
7273<h5>Arguments:</h5>
7274<p>The intrinsic takes two arguments, the first a pointer to an integer value
7275 and the second an integer value. The result is also an integer value. These
7276 integer types can have any bit width, but they must all have the same bit
7277 width. The targets may only lower integer representations they support.</p>
7278
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7279<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7280<p>This intrinsic does a series of operations atomically. It first loads the
7281 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7282 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]7283
7284<h5>Examples:</h5>
7285<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7286%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7287%ptr = bitcast i8* %mallocP to i32*
7288 store i32 4, %ptr
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7289%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7290 <i>; yields {i32}:result1 = 4</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7291%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7292 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7293%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7294 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7295%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7296</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7297
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7298</div>
7299
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7300<!-- _______________________________________________________________________ -->
7301<div class="doc_subsubsection">
7302 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7303
7304</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7305
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7306<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7307
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7308<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7309<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7310 any integer bit width and for different address spaces. Not all targets
7311 support all bit widths however.</p>
7312
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7313<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7314 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7315 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7316 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7317 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]7318</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7319
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7320<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7321<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7322 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7323
7324<h5>Arguments:</h5>
7325<p>The intrinsic takes two arguments, the first a pointer to an integer value
7326 and the second an integer value. The result is also an integer value. These
7327 integer types can have any bit width, but they must all have the same bit
7328 width. The targets may only lower integer representations they support.</p>
7329
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7330<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7331<p>This intrinsic does a series of operations atomically. It first loads the
7332 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7333 result to <tt>ptr</tt>. It yields the original value stored
7334 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7335
7336<h5>Examples:</h5>
7337<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7338%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7339%ptr = bitcast i8* %mallocP to i32*
7340 store i32 8, %ptr
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7341%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7342 <i>; yields {i32}:result1 = 8</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7343%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7344 <i>; yields {i32}:result2 = 4</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7345%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7346 <i>; yields {i32}:result3 = 2</i>
7347%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7348</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7349
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7350</div>
7351
7352<!-- _______________________________________________________________________ -->
7353<div class="doc_subsubsection">
7354 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7355 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7356 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7357 <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]7358</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7359
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7360<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7361
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7362<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7363<p>These are overloaded intrinsics. You can
7364 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7365 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7366 bit width and for different address spaces. Not all targets support all bit
7367 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7368
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7369<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7370 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7371 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7372 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7373 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]7374</pre>
7375
7376<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7377 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7378 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7379 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7380 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]7381</pre>
7382
7383<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7384 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7385 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7386 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7387 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]7388</pre>
7389
7390<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7391 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7392 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7393 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7394 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]7395</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7396
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7397<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7398<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7399 the value stored in memory at <tt>ptr</tt>. It yields the original value
7400 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7401
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7402<h5>Arguments:</h5>
7403<p>These intrinsics take two arguments, the first a pointer to an integer value
7404 and the second an integer value. The result is also an integer value. These
7405 integer types can have any bit width, but they must all have the same bit
7406 width. The targets may only lower integer representations they support.</p>
7407
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7408<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7409<p>These intrinsics does a series of operations atomically. They first load the
7410 value stored at <tt>ptr</tt>. They then do the bitwise
7411 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7412 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7413
7414<h5>Examples:</h5>
7415<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7416%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7417%ptr = bitcast i8* %mallocP to i32*
7418 store i32 0x0F0F, %ptr
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7419%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7420 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7421%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7422 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7423%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7424 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7425%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7426 <i>; yields {i32}:result3 = FF</i>
7427%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7428</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7429
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7430</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7431
7432<!-- _______________________________________________________________________ -->
7433<div class="doc_subsubsection">
7434 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7435 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7436 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7437 <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]7438</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7439
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7440<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7441
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7442<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7443<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7444 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7445 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7446 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7447
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7448<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7449 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7450 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7451 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7452 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]7453</pre>
7454
7455<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7456 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7457 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7458 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7459 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]7460</pre>
7461
7462<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7463 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7464 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7465 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7466 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]7467</pre>
7468
7469<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7470 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7471 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7472 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7473 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]7474</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7475
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7476<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7477<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7478 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7479 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7480
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7481<h5>Arguments:</h5>
7482<p>These intrinsics take two arguments, the first a pointer to an integer value
7483 and the second an integer value. The result is also an integer value. These
7484 integer types can have any bit width, but they must all have the same bit
7485 width. The targets may only lower integer representations they support.</p>
7486
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7487<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7488<p>These intrinsics does a series of operations atomically. They first load the
7489 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7490 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7491 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7492
7493<h5>Examples:</h5>
7494<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7495%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7496%ptr = bitcast i8* %mallocP to i32*
7497 store i32 7, %ptr
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7498%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7499 <i>; yields {i32}:result0 = 7</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7500%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7501 <i>; yields {i32}:result1 = -2</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7502%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7503 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7504%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7505 <i>; yields {i32}:result3 = 8</i>
7506%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7507</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7508
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7509</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7510
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7511
7512<!-- ======================================================================= -->
7513<div class="doc_subsection">
7514 <a name="int_memorymarkers">Memory Use Markers</a>
7515</div>
7516
7517<div class="doc_text">
7518
7519<p>This class of intrinsics exists to information about the lifetime of memory
7520 objects and ranges where variables are immutable.</p>
7521
7522</div>
7523
7524<!-- _______________________________________________________________________ -->
7525<div class="doc_subsubsection">
7526 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7527</div>
7528
7529<div class="doc_text">
7530
7531<h5>Syntax:</h5>
7532<pre>
7533 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7534</pre>
7535
7536<h5>Overview:</h5>
7537<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7538 object's lifetime.</p>
7539
7540<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7541<p>The first argument is a constant integer representing the size of the
7542 object, or -1 if it is variable sized. The second argument is a pointer to
7543 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7544
7545<h5>Semantics:</h5>
7546<p>This intrinsic indicates that before this point in the code, the value of the
7547 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]7548 never be used and has an undefined value. A load from the pointer that
7549 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7550 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7551
7552</div>
7553
7554<!-- _______________________________________________________________________ -->
7555<div class="doc_subsubsection">
7556 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7557</div>
7558
7559<div class="doc_text">
7560
7561<h5>Syntax:</h5>
7562<pre>
7563 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7564</pre>
7565
7566<h5>Overview:</h5>
7567<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7568 object's lifetime.</p>
7569
7570<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7571<p>The first argument is a constant integer representing the size of the
7572 object, or -1 if it is variable sized. The second argument is a pointer to
7573 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7574
7575<h5>Semantics:</h5>
7576<p>This intrinsic indicates that after this point in the code, the value of the
7577 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7578 never be used and has an undefined value. Any stores into the memory object
7579 following this intrinsic may be removed as dead.
7580
7581</div>
7582
7583<!-- _______________________________________________________________________ -->
7584<div class="doc_subsubsection">
7585 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7586</div>
7587
7588<div class="doc_text">
7589
7590<h5>Syntax:</h5>
7591<pre>
7592 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7593</pre>
7594
7595<h5>Overview:</h5>
7596<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7597 a memory object will not change.</p>
7598
7599<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7600<p>The first argument is a constant integer representing the size of the
7601 object, or -1 if it is variable sized. The second argument is a pointer to
7602 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7603
7604<h5>Semantics:</h5>
7605<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7606 the return value, the referenced memory location is constant and
7607 unchanging.</p>
7608
7609</div>
7610
7611<!-- _______________________________________________________________________ -->
7612<div class="doc_subsubsection">
7613 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7614</div>
7615
7616<div class="doc_text">
7617
7618<h5>Syntax:</h5>
7619<pre>
7620 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7621</pre>
7622
7623<h5>Overview:</h5>
7624<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7625 a memory object are mutable.</p>
7626
7627<h5>Arguments:</h5>
7628<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7629 The second argument is a constant integer representing the size of the
7630 object, or -1 if it is variable sized and the third argument is a pointer
7631 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7632
7633<h5>Semantics:</h5>
7634<p>This intrinsic indicates that the memory is mutable again.</p>
7635
7636</div>
7637
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7638<!-- ======================================================================= -->
7639<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7640 <a name="int_general">General Intrinsics</a>
7641</div>
7642
7643<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7644
7645<p>This class of intrinsics is designed to be generic and has no specific
7646 purpose.</p>
7647
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7648</div>
7649
7650<!-- _______________________________________________________________________ -->
7651<div class="doc_subsubsection">
7652 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7653</div>
7654
7655<div class="doc_text">
7656
7657<h5>Syntax:</h5>
7658<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7659 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]7660</pre>
7661
7662<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7663<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7664
7665<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7666<p>The first argument is a pointer to a value, the second is a pointer to a
7667 global string, the third is a pointer to a global string which is the source
7668 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7669
7670<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7671<p>This intrinsic allows annotation of local variables with arbitrary strings.
7672 This can be useful for special purpose optimizations that want to look for
7673 these annotations. These have no other defined use, they are ignored by code
7674 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7675
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7676</div>
7677
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7678<!-- _______________________________________________________________________ -->
7679<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7680 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7681</div>
7682
7683<div class="doc_text">
7684
7685<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7686<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7687 any integer bit width.</p>
7688
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7689<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7690 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7691 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7692 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7693 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7694 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]7695</pre>
7696
7697<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7698<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7699
7700<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7701<p>The first argument is an integer value (result of some expression), the
7702 second is a pointer to a global string, the third is a pointer to a global
7703 string which is the source file name, and the last argument is the line
7704 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7705
7706<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7707<p>This intrinsic allows annotations to be put on arbitrary expressions with
7708 arbitrary strings. This can be useful for special purpose optimizations that
7709 want to look for these annotations. These have no other defined use, they
7710 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7711
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7712</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7713
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7714<!-- _______________________________________________________________________ -->
7715<div class="doc_subsubsection">
7716 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7717</div>
7718
7719<div class="doc_text">
7720
7721<h5>Syntax:</h5>
7722<pre>
7723 declare void @llvm.trap()
7724</pre>
7725
7726<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7727<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7728
7729<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7730<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7731
7732<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7733<p>This intrinsics is lowered to the target dependent trap instruction. If the
7734 target does not have a trap instruction, this intrinsic will be lowered to
7735 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7736
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7737</div>
7738
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7739<!-- _______________________________________________________________________ -->
7740<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7741 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7742</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7743
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7744<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7745
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7746<h5>Syntax:</h5>
7747<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7748 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7749</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7750
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7751<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7752<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7753 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7754 ensure that it is placed on the stack before local variables.</p>
7755
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7756<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7757<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7758 arguments. The first argument is the value loaded from the stack
7759 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7760 that has enough space to hold the value of the guard.</p>
7761
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7762<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7763<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7764 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7765 stack. This is to ensure that if a local variable on the stack is
7766 overwritten, it will destroy the value of the guard. When the function exits,
7767 the guard on the stack is checked against the original guard. If they're
7768 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7769 function.</p>
7770
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7771</div>
7772
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7773<!-- _______________________________________________________________________ -->
7774<div class="doc_subsubsection">
7775 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7776</div>
7777
7778<div class="doc_text">
7779
7780<h5>Syntax:</h5>
7781<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7782 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7783 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7784</pre>
7785
7786<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7787<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher184f44d2010-01-08 21:42:39 +0000[diff] [blame]7788 to the optimizers to discover at compile time either a) when an
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7789 operation like memcpy will either overflow a buffer that corresponds to
7790 an object, or b) to determine that a runtime check for overflow isn't
7791 necessary. An object in this context means an allocation of a
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7792 specific class, structure, array, or other object.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7793
7794<h5>Arguments:</h5>
7795<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7796 argument is a pointer to or into the <tt>object</tt>. The second argument
7797 is a boolean 0 or 1. This argument determines whether you want the
7798 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7799 1, variables are not allowed.</p>
7800
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7801<h5>Semantics:</h5>
7802<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7803 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7804 (depending on the <tt>type</tt> argument if the size cannot be determined
7805 at compile time.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7806
7807</div>
7808
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7809<!-- *********************************************************************** -->
7810<hr>
7811<address>
7812 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7813 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7814 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7815 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7816
7817 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7818 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7819 Last modified: $Date$
7820</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7821
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7822</body>
7823</html>