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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / e0787286429c486909bd3b01b5dfedacbc2d7394 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
27 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
28 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
29 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
30 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
31 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
32 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
33 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner0fee5c22009-10-10 18:26:06 +0000[diff] [blame]34 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]35 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
36 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
37 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]39 </ol>
40 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]41 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]42 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]43 <li><a href="#globalvars">Global Variables</a></li>
44 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]45 <li><a href="#aliasstructure">Aliases</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]46 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]47 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]48 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]49 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
50 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]51 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]52 </ol>
53 </li>
54 <li><a href="#typesystem">Type System</a>
55 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]56 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]57 <li><a href="#t_primitive">Primitive Types</a>
58 <ol>
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]59 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_floating">Floating Point Types</a></li>
61 <li><a href="#t_void">Void Type</a></li>
62 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]63 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]64 </ol>
65 </li>
66 <li><a href="#t_derived">Derived Types</a>
67 <ol>
68 <li><a href="#t_array">Array Type</a></li>
69 <li><a href="#t_function">Function Type</a></li>
70 <li><a href="#t_pointer">Pointer Type</a></li>
71 <li><a href="#t_struct">Structure Type</a></li>
72 <li><a href="#t_pstruct">Packed Structure Type</a></li>
73 <li><a href="#t_vector">Vector Type</a></li>
74 <li><a href="#t_opaque">Opaque Type</a></li>
75 </ol>
76 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]77 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]78 </ol>
79 </li>
80 <li><a href="#constants">Constants</a>
81 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]82 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]83 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]84 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
85 <li><a href="#undefvalues">Undefined Values</a></li>
86 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]87 <li><a href="#metadata">Embedded Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]88 </ol>
89 </li>
90 <li><a href="#othervalues">Other Values</a>
91 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]92 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]93 </ol>
94 </li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]95 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
96 <ol>
97 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]98 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
99 Global Variable</a></li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]100 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
101 Global Variable</a></li>
102 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
103 Global Variable</a></li>
104 </ol>
105 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]106 <li><a href="#instref">Instruction Reference</a>
107 <ol>
108 <li><a href="#terminators">Terminator Instructions</a>
109 <ol>
110 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
111 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
112 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame^]113 <li><a href="#i_indbr">'<tt>indbr</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]114 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
115 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
116 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
117 </ol>
118 </li>
119 <li><a href="#binaryops">Binary Operations</a>
120 <ol>
121 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]122 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]123 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]124 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]125 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]126 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]127 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
128 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
129 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
130 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
131 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
132 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
133 </ol>
134 </li>
135 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
136 <ol>
137 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
138 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
139 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
140 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
141 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
142 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
143 </ol>
144 </li>
145 <li><a href="#vectorops">Vector Operations</a>
146 <ol>
147 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
148 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
149 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
150 </ol>
151 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]152 <li><a href="#aggregateops">Aggregate Operations</a>
153 <ol>
154 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
155 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
156 </ol>
157 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]158 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
159 <ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]160 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
161 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
162 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
163 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
164 </ol>
165 </li>
166 <li><a href="#convertops">Conversion Operations</a>
167 <ol>
168 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
169 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
170 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
171 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
172 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
173 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
174 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
175 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
176 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
177 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
178 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
179 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
180 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]181 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]182 <li><a href="#otherops">Other Operations</a>
183 <ol>
184 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
185 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
186 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
187 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
188 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
189 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
190 </ol>
191 </li>
192 </ol>
193 </li>
194 <li><a href="#intrinsics">Intrinsic Functions</a>
195 <ol>
196 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
197 <ol>
198 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
199 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
200 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
201 </ol>
202 </li>
203 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
204 <ol>
205 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
206 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
207 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
208 </ol>
209 </li>
210 <li><a href="#int_codegen">Code Generator Intrinsics</a>
211 <ol>
212 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
213 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
214 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
215 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
216 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
217 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
218 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
219 </ol>
220 </li>
221 <li><a href="#int_libc">Standard C Library Intrinsics</a>
222 <ol>
223 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
224 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
225 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
226 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
227 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]228 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
229 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
230 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]231 </ol>
232 </li>
233 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
234 <ol>
235 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
236 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
237 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
238 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]239 </ol>
240 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]241 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
242 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]243 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
244 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
245 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
246 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
247 <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]248 <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]249 </ol>
250 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]251 <li><a href="#int_debugger">Debugger intrinsics</a></li>
252 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]253 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]254 <ol>
255 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]256 </ol>
257 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]258 <li><a href="#int_atomics">Atomic intrinsics</a>
259 <ol>
260 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
261 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
262 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
263 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
264 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
265 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
266 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
267 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
268 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
269 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
270 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
271 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
272 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
273 </ol>
274 </li>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]275 <li><a href="#int_memorymarkers">Memory Use Markers</a>
276 <ol>
277 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
278 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
279 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
280 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
281 </ol>
282 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]283 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]284 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]285 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]286 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]287 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]288 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]289 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]290 '<tt>llvm.trap</tt>' Intrinsic</a></li>
291 <li><a href="#int_stackprotector">
292 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]293 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]294 </li>
295 </ol>
296 </li>
297</ol>
298
299<div class="doc_author">
300 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
301 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
302</div>
303
304<!-- *********************************************************************** -->
305<div class="doc_section"> <a name="abstract">Abstract </a></div>
306<!-- *********************************************************************** -->
307
308<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]309
310<p>This document is a reference manual for the LLVM assembly language. LLVM is
311 a Static Single Assignment (SSA) based representation that provides type
312 safety, low-level operations, flexibility, and the capability of representing
313 'all' high-level languages cleanly. It is the common code representation
314 used throughout all phases of the LLVM compilation strategy.</p>
315
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]316</div>
317
318<!-- *********************************************************************** -->
319<div class="doc_section"> <a name="introduction">Introduction</a> </div>
320<!-- *********************************************************************** -->
321
322<div class="doc_text">
323
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]324<p>The LLVM code representation is designed to be used in three different forms:
325 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
326 for fast loading by a Just-In-Time compiler), and as a human readable
327 assembly language representation. This allows LLVM to provide a powerful
328 intermediate representation for efficient compiler transformations and
329 analysis, while providing a natural means to debug and visualize the
330 transformations. The three different forms of LLVM are all equivalent. This
331 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]332
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]333<p>The LLVM representation aims to be light-weight and low-level while being
334 expressive, typed, and extensible at the same time. It aims to be a
335 "universal IR" of sorts, by being at a low enough level that high-level ideas
336 may be cleanly mapped to it (similar to how microprocessors are "universal
337 IR's", allowing many source languages to be mapped to them). By providing
338 type information, LLVM can be used as the target of optimizations: for
339 example, through pointer analysis, it can be proven that a C automatic
340 variable is never accessed outside of the current function... allowing it to
341 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]342
343</div>
344
345<!-- _______________________________________________________________________ -->
346<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
347
348<div class="doc_text">
349
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]350<p>It is important to note that this document describes 'well formed' LLVM
351 assembly language. There is a difference between what the parser accepts and
352 what is considered 'well formed'. For example, the following instruction is
353 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]354
355<div class="doc_code">
356<pre>
357%x = <a href="#i_add">add</a> i32 1, %x
358</pre>
359</div>
360
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]361<p>...because the definition of <tt>%x</tt> does not dominate all of its
362 uses. The LLVM infrastructure provides a verification pass that may be used
363 to verify that an LLVM module is well formed. This pass is automatically run
364 by the parser after parsing input assembly and by the optimizer before it
365 outputs bitcode. The violations pointed out by the verifier pass indicate
366 bugs in transformation passes or input to the parser.</p>
367
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]368</div>
369
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]370<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]371
372<!-- *********************************************************************** -->
373<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
374<!-- *********************************************************************** -->
375
376<div class="doc_text">
377
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]378<p>LLVM identifiers come in two basic types: global and local. Global
379 identifiers (functions, global variables) begin with the <tt>'@'</tt>
380 character. Local identifiers (register names, types) begin with
381 the <tt>'%'</tt> character. Additionally, there are three different formats
382 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]383
384<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]385 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]386 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
387 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
388 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
389 other characters in their names can be surrounded with quotes. Special
390 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
391 ASCII code for the character in hexadecimal. In this way, any character
392 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]393
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]394 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]395 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]396
397 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]398 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]399</ol>
400
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]401<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]402 don't need to worry about name clashes with reserved words, and the set of
403 reserved words may be expanded in the future without penalty. Additionally,
404 unnamed identifiers allow a compiler to quickly come up with a temporary
405 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]406
407<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]408 languages. There are keywords for different opcodes
409 ('<tt><a href="#i_add">add</a></tt>',
410 '<tt><a href="#i_bitcast">bitcast</a></tt>',
411 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
412 ('<tt><a href="#t_void">void</a></tt>',
413 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
414 reserved words cannot conflict with variable names, because none of them
415 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]416
417<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]418 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]419
420<p>The easy way:</p>
421
422<div class="doc_code">
423<pre>
424%result = <a href="#i_mul">mul</a> i32 %X, 8
425</pre>
426</div>
427
428<p>After strength reduction:</p>
429
430<div class="doc_code">
431<pre>
432%result = <a href="#i_shl">shl</a> i32 %X, i8 3
433</pre>
434</div>
435
436<p>And the hard way:</p>
437
438<div class="doc_code">
439<pre>
440<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
441<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
442%result = <a href="#i_add">add</a> i32 %1, %1
443</pre>
444</div>
445
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]446<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
447 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]448
449<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]450 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]451 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]452
453 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]454 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]455
456 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]457</ol>
458
459<p>...and it also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]460 demonstrating instructions, we will follow an instruction with a comment that
461 defines the type and name of value produced. Comments are shown in italic
462 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]463
464</div>
465
466<!-- *********************************************************************** -->
467<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
468<!-- *********************************************************************** -->
469
470<!-- ======================================================================= -->
471<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
472</div>
473
474<div class="doc_text">
475
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]476<p>LLVM programs are composed of "Module"s, each of which is a translation unit
477 of the input programs. Each module consists of functions, global variables,
478 and symbol table entries. Modules may be combined together with the LLVM
479 linker, which merges function (and global variable) definitions, resolves
480 forward declarations, and merges symbol table entries. Here is an example of
481 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]482
483<div class="doc_code">
484<pre><i>; Declare the string constant as a global constant...</i>
485<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
486 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
487
488<i>; External declaration of the puts function</i>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]489<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]490
491<i>; Definition of main function</i>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]492define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]493 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]494 %cast210 = <a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]495 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]496
497 <i>; Call puts function to write out the string to stdout...</i>
498 <a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]499 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]500 <a
501 href="#i_ret">ret</a> i32 0<br>}<br>
502</pre>
503</div>
504
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]505<p>This example is made up of a <a href="#globalvars">global variable</a> named
506 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
507 a <a href="#functionstructure">function definition</a> for
508 "<tt>main</tt>".</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]509
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]510<p>In general, a module is made up of a list of global values, where both
511 functions and global variables are global values. Global values are
512 represented by a pointer to a memory location (in this case, a pointer to an
513 array of char, and a pointer to a function), and have one of the
514 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]515
516</div>
517
518<!-- ======================================================================= -->
519<div class="doc_subsection">
520 <a name="linkage">Linkage Types</a>
521</div>
522
523<div class="doc_text">
524
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]525<p>All Global Variables and Functions have one of the following types of
526 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]527
528<dl>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]529 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]530 <dd>Global values with private linkage are only directly accessible by objects
531 in the current module. In particular, linking code into a module with an
532 private global value may cause the private to be renamed as necessary to
533 avoid collisions. Because the symbol is private to the module, all
534 references can be updated. This doesn't show up in any symbol table in the
535 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]536
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]537 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt>: </dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]538 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattner06c1ecc2009-08-24 04:32:16 +0000[diff] [blame]539 removed by the linker after evaluation. Note that (unlike private
540 symbols) linker_private symbols are subject to coalescing by the linker:
541 weak symbols get merged and redefinitions are rejected. However, unlike
542 normal strong symbols, they are removed by the linker from the final
543 linked image (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]544
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]545 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]546 <dd>Similar to private, but the value shows as a local symbol
547 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
548 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]549
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]550 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]551 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]552 into the object file corresponding to the LLVM module. They exist to
553 allow inlining and other optimizations to take place given knowledge of
554 the definition of the global, which is known to be somewhere outside the
555 module. Globals with <tt>available_externally</tt> linkage are allowed to
556 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
557 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]558
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]559 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]560 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]561 the same name when linkage occurs. This is typically used to implement
562 inline functions, templates, or other code which must be generated in each
563 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
564 allowed to be discarded.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]565
566 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]567 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
568 <tt>linkonce</tt> linkage, except that unreferenced globals with
569 <tt>weak</tt> linkage may not be discarded. This is used for globals that
570 are declared "weak" in C source code.</dd>
571
572 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
573 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
574 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
575 global scope.
576 Symbols with "<tt>common</tt>" linkage are merged in the same way as
577 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]578 <tt>common</tt> symbols may not have an explicit section,
579 must have a zero initializer, and may not be marked '<a
580 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
581 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]582
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]583
584 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]585 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]586 pointer to array type. When two global variables with appending linkage
587 are linked together, the two global arrays are appended together. This is
588 the LLVM, typesafe, equivalent of having the system linker append together
589 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]590
591 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]592 <dd>The semantics of this linkage follow the ELF object file model: the symbol
593 is weak until linked, if not linked, the symbol becomes null instead of
594 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]595
Chris Lattner0fee5c22009-10-10 18:26:06 +0000[diff] [blame]596 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt>: </dt>
597 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]598 <dd>Some languages allow differing globals to be merged, such as two functions
599 with different semantics. Other languages, such as <tt>C++</tt>, ensure
600 that only equivalent globals are ever merged (the "one definition rule" -
601 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
602 and <tt>weak_odr</tt> linkage types to indicate that the global will only
603 be merged with equivalent globals. These linkage types are otherwise the
604 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]605
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]606 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]607 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]608 visible, meaning that it participates in linkage and can be used to
609 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]610</dl>
611
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]612<p>The next two types of linkage are targeted for Microsoft Windows platform
613 only. They are designed to support importing (exporting) symbols from (to)
614 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]615
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]616<dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]617 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]618 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]619 or variable via a global pointer to a pointer that is set up by the DLL
620 exporting the symbol. On Microsoft Windows targets, the pointer name is
621 formed by combining <code>__imp_</code> and the function or variable
622 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]623
624 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]625 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]626 pointer to a pointer in a DLL, so that it can be referenced with the
627 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
628 name is formed by combining <code>__imp_</code> and the function or
629 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]630</dl>
631
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]632<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
633 another module defined a "<tt>.LC0</tt>" variable and was linked with this
634 one, one of the two would be renamed, preventing a collision. Since
635 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
636 declarations), they are accessible outside of the current module.</p>
637
638<p>It is illegal for a function <i>declaration</i> to have any linkage type
639 other than "externally visible", <tt>dllimport</tt>
640 or <tt>extern_weak</tt>.</p>
641
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]642<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]643 or <tt>weak_odr</tt> linkages.</p>
644
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]645</div>
646
647<!-- ======================================================================= -->
648<div class="doc_subsection">
649 <a name="callingconv">Calling Conventions</a>
650</div>
651
652<div class="doc_text">
653
654<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]655 and <a href="#i_invoke">invokes</a> can all have an optional calling
656 convention specified for the call. The calling convention of any pair of
657 dynamic caller/callee must match, or the behavior of the program is
658 undefined. The following calling conventions are supported by LLVM, and more
659 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]660
661<dl>
662 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]663 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]664 specified) matches the target C calling conventions. This calling
665 convention supports varargs function calls and tolerates some mismatch in
666 the declared prototype and implemented declaration of the function (as
667 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]668
669 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]670 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]671 (e.g. by passing things in registers). This calling convention allows the
672 target to use whatever tricks it wants to produce fast code for the
673 target, without having to conform to an externally specified ABI
674 (Application Binary Interface). Implementations of this convention should
675 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
676 optimization</a> to be supported. This calling convention does not
677 support varargs and requires the prototype of all callees to exactly match
678 the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]679
680 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]681 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]682 as possible under the assumption that the call is not commonly executed.
683 As such, these calls often preserve all registers so that the call does
684 not break any live ranges in the caller side. This calling convention
685 does not support varargs and requires the prototype of all callees to
686 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]687
688 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]689 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]690 target-specific calling conventions to be used. Target specific calling
691 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]692</dl>
693
694<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]695 support Pascal conventions or any other well-known target-independent
696 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]697
698</div>
699
700<!-- ======================================================================= -->
701<div class="doc_subsection">
702 <a name="visibility">Visibility Styles</a>
703</div>
704
705<div class="doc_text">
706
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]707<p>All Global Variables and Functions have one of the following visibility
708 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]709
710<dl>
711 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]712 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]713 that the declaration is visible to other modules and, in shared libraries,
714 means that the declared entity may be overridden. On Darwin, default
715 visibility means that the declaration is visible to other modules. Default
716 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]717
718 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]719 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]720 object if they are in the same shared object. Usually, hidden visibility
721 indicates that the symbol will not be placed into the dynamic symbol
722 table, so no other module (executable or shared library) can reference it
723 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]724
725 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]726 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]727 the dynamic symbol table, but that references within the defining module
728 will bind to the local symbol. That is, the symbol cannot be overridden by
729 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]730</dl>
731
732</div>
733
734<!-- ======================================================================= -->
735<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]736 <a name="namedtypes">Named Types</a>
737</div>
738
739<div class="doc_text">
740
741<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]742 it easier to read the IR and make the IR more condensed (particularly when
743 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]744
745<div class="doc_code">
746<pre>
747%mytype = type { %mytype*, i32 }
748</pre>
749</div>
750
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]751<p>You may give a name to any <a href="#typesystem">type</a> except
752 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
753 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]754
755<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]756 and that you can therefore specify multiple names for the same type. This
757 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
758 uses structural typing, the name is not part of the type. When printing out
759 LLVM IR, the printer will pick <em>one name</em> to render all types of a
760 particular shape. This means that if you have code where two different
761 source types end up having the same LLVM type, that the dumper will sometimes
762 print the "wrong" or unexpected type. This is an important design point and
763 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]764
765</div>
766
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]767<!-- ======================================================================= -->
768<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]769 <a name="globalvars">Global Variables</a>
770</div>
771
772<div class="doc_text">
773
774<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]775 instead of run-time. Global variables may optionally be initialized, may
776 have an explicit section to be placed in, and may have an optional explicit
777 alignment specified. A variable may be defined as "thread_local", which
778 means that it will not be shared by threads (each thread will have a
779 separated copy of the variable). A variable may be defined as a global
780 "constant," which indicates that the contents of the variable
781 will <b>never</b> be modified (enabling better optimization, allowing the
782 global data to be placed in the read-only section of an executable, etc).
783 Note that variables that need runtime initialization cannot be marked
784 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]785
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]786<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
787 constant, even if the final definition of the global is not. This capability
788 can be used to enable slightly better optimization of the program, but
789 requires the language definition to guarantee that optimizations based on the
790 'constantness' are valid for the translation units that do not include the
791 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]792
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]793<p>As SSA values, global variables define pointer values that are in scope
794 (i.e. they dominate) all basic blocks in the program. Global variables
795 always define a pointer to their "content" type because they describe a
796 region of memory, and all memory objects in LLVM are accessed through
797 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]798
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]799<p>A global variable may be declared to reside in a target-specific numbered
800 address space. For targets that support them, address spaces may affect how
801 optimizations are performed and/or what target instructions are used to
802 access the variable. The default address space is zero. The address space
803 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]804
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]805<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]806 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]807
808<p>An explicit alignment may be specified for a global. If not present, or if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]809 the alignment is set to zero, the alignment of the global is set by the
810 target to whatever it feels convenient. If an explicit alignment is
811 specified, the global is forced to have at least that much alignment. All
812 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]813
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]814<p>For example, the following defines a global in a numbered address space with
815 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]816
817<div class="doc_code">
818<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]819@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]820</pre>
821</div>
822
823</div>
824
825
826<!-- ======================================================================= -->
827<div class="doc_subsection">
828 <a name="functionstructure">Functions</a>
829</div>
830
831<div class="doc_text">
832
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]833<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
834 optional <a href="#linkage">linkage type</a>, an optional
835 <a href="#visibility">visibility style</a>, an optional
836 <a href="#callingconv">calling convention</a>, a return type, an optional
837 <a href="#paramattrs">parameter attribute</a> for the return type, a function
838 name, a (possibly empty) argument list (each with optional
839 <a href="#paramattrs">parameter attributes</a>), optional
840 <a href="#fnattrs">function attributes</a>, an optional section, an optional
841 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
842 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]843
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]844<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
845 optional <a href="#linkage">linkage type</a>, an optional
846 <a href="#visibility">visibility style</a>, an optional
847 <a href="#callingconv">calling convention</a>, a return type, an optional
848 <a href="#paramattrs">parameter attribute</a> for the return type, a function
849 name, a possibly empty list of arguments, an optional alignment, and an
850 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]851
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]852<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]853 (Control Flow Graph) for the function. Each basic block may optionally start
854 with a label (giving the basic block a symbol table entry), contains a list
855 of instructions, and ends with a <a href="#terminators">terminator</a>
856 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]857
858<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]859 executed on entrance to the function, and it is not allowed to have
860 predecessor basic blocks (i.e. there can not be any branches to the entry
861 block of a function). Because the block can have no predecessors, it also
862 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]863
864<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]865 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]866
867<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]868 the alignment is set to zero, the alignment of the function is set by the
869 target to whatever it feels convenient. If an explicit alignment is
870 specified, the function is forced to have at least that much alignment. All
871 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]872
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]873<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]874<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]875<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]876define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]877 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
878 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
879 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
880 [<a href="#gc">gc</a>] { ... }
881</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]882</div>
883
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]884</div>
885
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]886<!-- ======================================================================= -->
887<div class="doc_subsection">
888 <a name="aliasstructure">Aliases</a>
889</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]890
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]891<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]892
893<p>Aliases act as "second name" for the aliasee value (which can be either
894 function, global variable, another alias or bitcast of global value). Aliases
895 may have an optional <a href="#linkage">linkage type</a>, and an
896 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]897
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]898<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]899<div class="doc_code">
900<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]901@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]902</pre>
903</div>
904
905</div>
906
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]907<!-- ======================================================================= -->
908<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]909
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]910<div class="doc_text">
911
912<p>The return type and each parameter of a function type may have a set of
913 <i>parameter attributes</i> associated with them. Parameter attributes are
914 used to communicate additional information about the result or parameters of
915 a function. Parameter attributes are considered to be part of the function,
916 not of the function type, so functions with different parameter attributes
917 can have the same function type.</p>
918
919<p>Parameter attributes are simple keywords that follow the type specified. If
920 multiple parameter attributes are needed, they are space separated. For
921 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]922
923<div class="doc_code">
924<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]925declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]926declare i32 @atoi(i8 zeroext)
927declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]928</pre>
929</div>
930
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]931<p>Note that any attributes for the function result (<tt>nounwind</tt>,
932 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]933
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]934<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]935
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]936<dl>
937 <dt><tt>zeroext</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]938 <dd>This indicates to the code generator that the parameter or return value
939 should be zero-extended to a 32-bit value by the caller (for a parameter)
940 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]941
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]942 <dt><tt>signext</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]943 <dd>This indicates to the code generator that the parameter or return value
944 should be sign-extended to a 32-bit value by the caller (for a parameter)
945 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]946
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]947 <dt><tt>inreg</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]948 <dd>This indicates that this parameter or return value should be treated in a
949 special target-dependent fashion during while emitting code for a function
950 call or return (usually, by putting it in a register as opposed to memory,
951 though some targets use it to distinguish between two different kinds of
952 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]953
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]954 <dt><tt><a name="byval">byval</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]955 <dd>This indicates that the pointer parameter should really be passed by value
956 to the function. The attribute implies that a hidden copy of the pointee
957 is made between the caller and the callee, so the callee is unable to
958 modify the value in the callee. This attribute is only valid on LLVM
959 pointer arguments. It is generally used to pass structs and arrays by
960 value, but is also valid on pointers to scalars. The copy is considered
961 to belong to the caller not the callee (for example,
962 <tt><a href="#readonly">readonly</a></tt> functions should not write to
963 <tt>byval</tt> parameters). This is not a valid attribute for return
964 values. The byval attribute also supports specifying an alignment with
965 the align attribute. This has a target-specific effect on the code
966 generator that usually indicates a desired alignment for the synthesized
967 stack slot.</dd>
968
969 <dt><tt>sret</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]970 <dd>This indicates that the pointer parameter specifies the address of a
971 structure that is the return value of the function in the source program.
972 This pointer must be guaranteed by the caller to be valid: loads and
973 stores to the structure may be assumed by the callee to not to trap. This
974 may only be applied to the first parameter. This is not a valid attribute
975 for return values. </dd>
976
977 <dt><tt>noalias</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]978 <dd>This indicates that the pointer does not alias any global or any other
979 parameter. The caller is responsible for ensuring that this is the
980 case. On a function return value, <tt>noalias</tt> additionally indicates
981 that the pointer does not alias any other pointers visible to the
982 caller. For further details, please see the discussion of the NoAlias
983 response in
984 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
985 analysis</a>.</dd>
986
987 <dt><tt>nocapture</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]988 <dd>This indicates that the callee does not make any copies of the pointer
989 that outlive the callee itself. This is not a valid attribute for return
990 values.</dd>
991
992 <dt><tt>nest</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]993 <dd>This indicates that the pointer parameter can be excised using the
994 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
995 attribute for return values.</dd>
996</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]997
998</div>
999
1000<!-- ======================================================================= -->
1001<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1002 <a name="gc">Garbage Collector Names</a>
1003</div>
1004
1005<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1006
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1007<p>Each function may specify a garbage collector name, which is simply a
1008 string:</p>
1009
1010<div class="doc_code">
1011<pre>
1012define void @f() gc "name" { ...
1013</pre>
1014</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1015
1016<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1017 collector which will cause the compiler to alter its output in order to
1018 support the named garbage collection algorithm.</p>
1019
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1020</div>
1021
1022<!-- ======================================================================= -->
1023<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1024 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1025</div>
1026
1027<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1028
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1029<p>Function attributes are set to communicate additional information about a
1030 function. Function attributes are considered to be part of the function, not
1031 of the function type, so functions with different parameter attributes can
1032 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1033
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1034<p>Function attributes are simple keywords that follow the type specified. If
1035 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1036
1037<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1038<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1039define void @f() noinline { ... }
1040define void @f() alwaysinline { ... }
1041define void @f() alwaysinline optsize { ... }
1042define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1043</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1044</div>
1045
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1046<dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1047 <dt><tt>alwaysinline</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1048 <dd>This attribute indicates that the inliner should attempt to inline this
1049 function into callers whenever possible, ignoring any active inlining size
1050 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1051
Dale Johannesen7fd6b0f2009-08-26 01:08:21 +0000[diff] [blame]1052 <dt><tt>inlinehint</tt></dt>
1053 <dd>This attribute indicates that the source code contained a hint that inlining
1054 this function is desirable (such as the "inline" keyword in C/C++). It
1055 is just a hint; it imposes no requirements on the inliner.</dd>
1056
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1057 <dt><tt>noinline</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1058 <dd>This attribute indicates that the inliner should never inline this
1059 function in any situation. This attribute may not be used together with
1060 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1061
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1062 <dt><tt>optsize</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1063 <dd>This attribute suggests that optimization passes and code generator passes
1064 make choices that keep the code size of this function low, and otherwise
1065 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1066
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1067 <dt><tt>noreturn</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1068 <dd>This function attribute indicates that the function never returns
1069 normally. This produces undefined behavior at runtime if the function
1070 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1071
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1072 <dt><tt>nounwind</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1073 <dd>This function attribute indicates that the function never returns with an
1074 unwind or exceptional control flow. If the function does unwind, its
1075 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1076
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1077 <dt><tt>readnone</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1078 <dd>This attribute indicates that the function computes its result (or decides
1079 to unwind an exception) based strictly on its arguments, without
1080 dereferencing any pointer arguments or otherwise accessing any mutable
1081 state (e.g. memory, control registers, etc) visible to caller functions.
1082 It does not write through any pointer arguments
1083 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1084 changes any state visible to callers. This means that it cannot unwind
1085 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1086 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1087
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1088 <dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1089 <dd>This attribute indicates that the function does not write through any
1090 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1091 arguments) or otherwise modify any state (e.g. memory, control registers,
1092 etc) visible to caller functions. It may dereference pointer arguments
1093 and read state that may be set in the caller. A readonly function always
1094 returns the same value (or unwinds an exception identically) when called
1095 with the same set of arguments and global state. It cannot unwind an
1096 exception by calling the <tt>C++</tt> exception throwing methods, but may
1097 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1098
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1099 <dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1100 <dd>This attribute indicates that the function should emit a stack smashing
1101 protector. It is in the form of a "canary"&mdash;a random value placed on
1102 the stack before the local variables that's checked upon return from the
1103 function to see if it has been overwritten. A heuristic is used to
1104 determine if a function needs stack protectors or not.<br>
1105<br>
1106 If a function that has an <tt>ssp</tt> attribute is inlined into a
1107 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1108 function will have an <tt>ssp</tt> attribute.</dd>
1109
1110 <dt><tt>sspreq</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1111 <dd>This attribute indicates that the function should <em>always</em> emit a
1112 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1113 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1114<br>
1115 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1116 function that doesn't have an <tt>sspreq</tt> attribute or which has
1117 an <tt>ssp</tt> attribute, then the resulting function will have
1118 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1119
1120 <dt><tt>noredzone</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1121 <dd>This attribute indicates that the code generator should not use a red
1122 zone, even if the target-specific ABI normally permits it.</dd>
1123
1124 <dt><tt>noimplicitfloat</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1125 <dd>This attributes disables implicit floating point instructions.</dd>
1126
1127 <dt><tt>naked</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1128 <dd>This attribute disables prologue / epilogue emission for the function.
1129 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1130</dl>
1131
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1132</div>
1133
1134<!-- ======================================================================= -->
1135<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1136 <a name="moduleasm">Module-Level Inline Assembly</a>
1137</div>
1138
1139<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1140
1141<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1142 the GCC "file scope inline asm" blocks. These blocks are internally
1143 concatenated by LLVM and treated as a single unit, but may be separated in
1144 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1145
1146<div class="doc_code">
1147<pre>
1148module asm "inline asm code goes here"
1149module asm "more can go here"
1150</pre>
1151</div>
1152
1153<p>The strings can contain any character by escaping non-printable characters.
1154 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]1155 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1156
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1157<p>The inline asm code is simply printed to the machine code .s file when
1158 assembly code is generated.</p>
1159
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1160</div>
1161
1162<!-- ======================================================================= -->
1163<div class="doc_subsection">
1164 <a name="datalayout">Data Layout</a>
1165</div>
1166
1167<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1168
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1169<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1170 data is to be laid out in memory. The syntax for the data layout is
1171 simply:</p>
1172
1173<div class="doc_code">
1174<pre>
1175target datalayout = "<i>layout specification</i>"
1176</pre>
1177</div>
1178
1179<p>The <i>layout specification</i> consists of a list of specifications
1180 separated by the minus sign character ('-'). Each specification starts with
1181 a letter and may include other information after the letter to define some
1182 aspect of the data layout. The specifications accepted are as follows:</p>
1183
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1184<dl>
1185 <dt><tt>E</tt></dt>
1186 <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]1187 bits with the most significance have the lowest address location.</dd>
1188
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1189 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1190 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1191 the bits with the least significance have the lowest address
1192 location.</dd>
1193
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1194 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1195 <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]1196 <i>preferred</i> alignments. All sizes are in bits. Specifying
1197 the <i>pref</i> alignment is optional. If omitted, the
1198 preceding <tt>:</tt> should be omitted too.</dd>
1199
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1200 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1201 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1202 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1203
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1204 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1205 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1206 <i>size</i>.</dd>
1207
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1208 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1209 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1210 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1211 (double).</dd>
1212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1213 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1214 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1215 <i>size</i>.</dd>
1216
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1217 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1218 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1219 <i>size</i>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1220</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1221
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1222<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1223 default set of specifications which are then (possibly) overriden by the
1224 specifications in the <tt>datalayout</tt> keyword. The default specifications
1225 are given in this list:</p>
1226
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1227<ul>
1228 <li><tt>E</tt> - big endian</li>
1229 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1230 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1231 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1232 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1233 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1234 <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]1235 alignment of 64-bits</li>
1236 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1237 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1238 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1239 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1240 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1241 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1242</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1243
1244<p>When LLVM is determining the alignment for a given type, it uses the
1245 following rules:</p>
1246
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1247<ol>
1248 <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]1249 specification is used.</li>
1250
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1251 <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]1252 smallest integer type that is larger than the bitwidth of the sought type
1253 is used. If none of the specifications are larger than the bitwidth then
1254 the the largest integer type is used. For example, given the default
1255 specifications above, the i7 type will use the alignment of i8 (next
1256 largest) while both i65 and i256 will use the alignment of i64 (largest
1257 specified).</li>
1258
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1259 <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]1260 largest vector type that is smaller than the sought vector type will be
1261 used as a fall back. This happens because &lt;128 x double&gt; can be
1262 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1263</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1264
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1265</div>
1266
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1267<!-- ======================================================================= -->
1268<div class="doc_subsection">
1269 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1270</div>
1271
1272<div class="doc_text">
1273
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1274<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1275with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1276is undefined. Pointer values are associated with address ranges
1277according to the following rules:</p>
1278
1279<ul>
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1280 <li>A pointer value formed from a
1281 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1282 is associated with the addresses associated with the first operand
1283 of the <tt>getelementptr</tt>.</li>
1284 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1285 range of the variable's storage.</li>
1286 <li>The result value of an allocation instruction is associated with
1287 the address range of the allocated storage.</li>
1288 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1289 no address.</li>
1290 <li>A pointer value formed by an
1291 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1292 address ranges of all pointer values that contribute (directly or
1293 indirectly) to the computation of the pointer's value.</li>
1294 <li>The result value of a
1295 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1296 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1297 <li>An integer constant other than zero or a pointer value returned
1298 from a function not defined within LLVM may be associated with address
1299 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1300 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1301 allocated by mechanisms provided by LLVM.</li>
1302 </ul>
1303
1304<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1305<tt><a href="#i_load">load</a></tt> merely indicates the size and
1306alignment of the memory from which to load, as well as the
1307interpretation of the value. The first operand of a
1308<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1309and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1310
1311<p>Consequently, type-based alias analysis, aka TBAA, aka
1312<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1313LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1314additional information which specialized optimization passes may use
1315to implement type-based alias analysis.</p>
1316
1317</div>
1318
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1319<!-- *********************************************************************** -->
1320<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1321<!-- *********************************************************************** -->
1322
1323<div class="doc_text">
1324
1325<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1326 intermediate representation. Being typed enables a number of optimizations
1327 to be performed on the intermediate representation directly, without having
1328 to do extra analyses on the side before the transformation. A strong type
1329 system makes it easier to read the generated code and enables novel analyses
1330 and transformations that are not feasible to perform on normal three address
1331 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1332
1333</div>
1334
1335<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1336<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1337Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1338
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1339<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1340
1341<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1342
1343<table border="1" cellspacing="0" cellpadding="4">
1344 <tbody>
1345 <tr><th>Classification</th><th>Types</th></tr>
1346 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1347 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1348 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1349 </tr>
1350 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1351 <td><a href="#t_floating">floating point</a></td>
1352 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1353 </tr>
1354 <tr>
1355 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1356 <td><a href="#t_integer">integer</a>,
1357 <a href="#t_floating">floating point</a>,
1358 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1359 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1360 <a href="#t_struct">structure</a>,
1361 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1362 <a href="#t_label">label</a>,
1363 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1364 </td>
1365 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1366 <tr>
1367 <td><a href="#t_primitive">primitive</a></td>
1368 <td><a href="#t_label">label</a>,
1369 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1370 <a href="#t_floating">floating point</a>,
1371 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1372 </tr>
1373 <tr>
1374 <td><a href="#t_derived">derived</a></td>
1375 <td><a href="#t_integer">integer</a>,
1376 <a href="#t_array">array</a>,
1377 <a href="#t_function">function</a>,
1378 <a href="#t_pointer">pointer</a>,
1379 <a href="#t_struct">structure</a>,
1380 <a href="#t_pstruct">packed structure</a>,
1381 <a href="#t_vector">vector</a>,
1382 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1383 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1384 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1385 </tbody>
1386</table>
1387
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1388<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1389 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1390 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1391
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1392</div>
1393
1394<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1395<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1396
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1397<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1398
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1399<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1400 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1401
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1402</div>
1403
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1404<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1405<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1406
1407<div class="doc_text">
1408
1409<h5>Overview:</h5>
1410<p>The integer type is a very simple type that simply specifies an arbitrary
1411 bit width for the integer type desired. Any bit width from 1 bit to
1412 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1413
1414<h5>Syntax:</h5>
1415<pre>
1416 iN
1417</pre>
1418
1419<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1420 value.</p>
1421
1422<h5>Examples:</h5>
1423<table class="layout">
1424 <tr class="layout">
1425 <td class="left"><tt>i1</tt></td>
1426 <td class="left">a single-bit integer.</td>
1427 </tr>
1428 <tr class="layout">
1429 <td class="left"><tt>i32</tt></td>
1430 <td class="left">a 32-bit integer.</td>
1431 </tr>
1432 <tr class="layout">
1433 <td class="left"><tt>i1942652</tt></td>
1434 <td class="left">a really big integer of over 1 million bits.</td>
1435 </tr>
1436</table>
1437
1438<p>Note that the code generator does not yet support large integer types to be
1439 used as function return types. The specific limit on how large a return type
1440 the code generator can currently handle is target-dependent; currently it's
1441 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
1442
1443</div>
1444
1445<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1446<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1447
1448<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1449
1450<table>
1451 <tbody>
1452 <tr><th>Type</th><th>Description</th></tr>
1453 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1454 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1455 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1456 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1457 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1458 </tbody>
1459</table>
1460
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1461</div>
1462
1463<!-- _______________________________________________________________________ -->
1464<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1465
1466<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1467
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1468<h5>Overview:</h5>
1469<p>The void type does not represent any value and has no size.</p>
1470
1471<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1472<pre>
1473 void
1474</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1475
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1476</div>
1477
1478<!-- _______________________________________________________________________ -->
1479<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1480
1481<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1482
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1483<h5>Overview:</h5>
1484<p>The label type represents code labels.</p>
1485
1486<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1487<pre>
1488 label
1489</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1490
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1491</div>
1492
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1493<!-- _______________________________________________________________________ -->
1494<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1495
1496<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1497
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1498<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1499<p>The metadata type represents embedded metadata. No derived types may be
1500 created from metadata except for <a href="#t_function">function</a>
1501 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1502
1503<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1504<pre>
1505 metadata
1506</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1507
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1508</div>
1509
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1510
1511<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1512<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1513
1514<div class="doc_text">
1515
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1516<p>The real power in LLVM comes from the derived types in the system. This is
1517 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1518 useful types. Each of these types contain one or more element types which
1519 may be a primitive type, or another derived type. For example, it is
1520 possible to have a two dimensional array, using an array as the element type
1521 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1522
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1523</div>
1524
1525<!-- _______________________________________________________________________ -->
1526<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1527
1528<div class="doc_text">
1529
1530<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1531<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1532 sequentially in memory. The array type requires a size (number of elements)
1533 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1534
1535<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1536<pre>
1537 [&lt;# elements&gt; x &lt;elementtype&gt;]
1538</pre>
1539
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1540<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1541 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1542
1543<h5>Examples:</h5>
1544<table class="layout">
1545 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1546 <td class="left"><tt>[40 x i32]</tt></td>
1547 <td class="left">Array of 40 32-bit integer values.</td>
1548 </tr>
1549 <tr class="layout">
1550 <td class="left"><tt>[41 x i32]</tt></td>
1551 <td class="left">Array of 41 32-bit integer values.</td>
1552 </tr>
1553 <tr class="layout">
1554 <td class="left"><tt>[4 x i8]</tt></td>
1555 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1556 </tr>
1557</table>
1558<p>Here are some examples of multidimensional arrays:</p>
1559<table class="layout">
1560 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1561 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1562 <td class="left">3x4 array of 32-bit integer values.</td>
1563 </tr>
1564 <tr class="layout">
1565 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1566 <td class="left">12x10 array of single precision floating point values.</td>
1567 </tr>
1568 <tr class="layout">
1569 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1570 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1571 </tr>
1572</table>
1573
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1574<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1575 length array. Normally, accesses past the end of an array are undefined in
1576 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1577 a special case, however, zero length arrays are recognized to be variable
1578 length. This allows implementation of 'pascal style arrays' with the LLVM
1579 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1580
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1581<p>Note that the code generator does not yet support large aggregate types to be
1582 used as function return types. The specific limit on how large an aggregate
1583 return type the code generator can currently handle is target-dependent, and
1584 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1585
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1586</div>
1587
1588<!-- _______________________________________________________________________ -->
1589<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1590
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1591<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1592
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1593<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1594<p>The function type can be thought of as a function signature. It consists of
1595 a return type and a list of formal parameter types. The return type of a
1596 function type is a scalar type, a void type, or a struct type. If the return
1597 type is a struct type then all struct elements must be of first class types,
1598 and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1599
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1600<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1601<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1602 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1603</pre>
1604
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1605<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]1606 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1607 which indicates that the function takes a variable number of arguments.
1608 Variable argument functions can access their arguments with
1609 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1610 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1611 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1612
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1613<h5>Examples:</h5>
1614<table class="layout">
1615 <tr class="layout">
1616 <td class="left"><tt>i32 (i32)</tt></td>
1617 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1618 </td>
1619 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1620 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1621 </tt></td>
1622 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1623 an <tt>i16</tt> that should be sign extended and a
1624 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1625 <tt>float</tt>.
1626 </td>
1627 </tr><tr class="layout">
1628 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1629 <td class="left">A vararg function that takes at least one
1630 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1631 which returns an integer. This is the signature for <tt>printf</tt> in
1632 LLVM.
1633 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1634 </tr><tr class="layout">
1635 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1636 <td class="left">A function taking an <tt>i32</tt>, returning a
1637 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1638 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1639 </tr>
1640</table>
1641
1642</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1643
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1644<!-- _______________________________________________________________________ -->
1645<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1646
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1647<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1648
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1649<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1650<p>The structure type is used to represent a collection of data members together
1651 in memory. The packing of the field types is defined to match the ABI of the
1652 underlying processor. The elements of a structure may be any type that has a
1653 size.</p>
1654
1655<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1656 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1657 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1658
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1659<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1660<pre>
1661 { &lt;type list&gt; }
1662</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1663
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1664<h5>Examples:</h5>
1665<table class="layout">
1666 <tr class="layout">
1667 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1668 <td class="left">A triple of three <tt>i32</tt> values</td>
1669 </tr><tr class="layout">
1670 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1671 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1672 second element is a <a href="#t_pointer">pointer</a> to a
1673 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1674 an <tt>i32</tt>.</td>
1675 </tr>
1676</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1677
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1678<p>Note that the code generator does not yet support large aggregate types to be
1679 used as function return types. The specific limit on how large an aggregate
1680 return type the code generator can currently handle is target-dependent, and
1681 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1682
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1683</div>
1684
1685<!-- _______________________________________________________________________ -->
1686<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1687</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1688
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1689<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1690
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1691<h5>Overview:</h5>
1692<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1693 together in memory. There is no padding between fields. Further, the
1694 alignment of a packed structure is 1 byte. The elements of a packed
1695 structure may be any type that has a size.</p>
1696
1697<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1698 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1699 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1700
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1701<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1702<pre>
1703 &lt; { &lt;type list&gt; } &gt;
1704</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1705
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1706<h5>Examples:</h5>
1707<table class="layout">
1708 <tr class="layout">
1709 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1710 <td class="left">A triple of three <tt>i32</tt> values</td>
1711 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1712 <td class="left">
1713<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1714 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1715 second element is a <a href="#t_pointer">pointer</a> to a
1716 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1717 an <tt>i32</tt>.</td>
1718 </tr>
1719</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1720
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1721</div>
1722
1723<!-- _______________________________________________________________________ -->
1724<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1725
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1726<div class="doc_text">
1727
1728<h5>Overview:</h5>
1729<p>As in many languages, the pointer type represents a pointer or reference to
1730 another object, which must live in memory. Pointer types may have an optional
1731 address space attribute defining the target-specific numbered address space
1732 where the pointed-to object resides. The default address space is zero.</p>
1733
1734<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1735 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1736
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1737<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1738<pre>
1739 &lt;type&gt; *
1740</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1741
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1742<h5>Examples:</h5>
1743<table class="layout">
1744 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1745 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1746 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1747 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1748 </tr>
1749 <tr class="layout">
1750 <td class="left"><tt>i32 (i32 *) *</tt></td>
1751 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1752 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1753 <tt>i32</tt>.</td>
1754 </tr>
1755 <tr class="layout">
1756 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1757 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1758 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1759 </tr>
1760</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1761
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1762</div>
1763
1764<!-- _______________________________________________________________________ -->
1765<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1766
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1767<div class="doc_text">
1768
1769<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1770<p>A vector type is a simple derived type that represents a vector of elements.
1771 Vector types are used when multiple primitive data are operated in parallel
1772 using a single instruction (SIMD). A vector type requires a size (number of
1773 elements) and an underlying primitive data type. Vectors must have a power
1774 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1775 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1776
1777<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1778<pre>
1779 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1780</pre>
1781
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1782<p>The number of elements is a constant integer value; elementtype may be any
1783 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1784
1785<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1786<table class="layout">
1787 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1788 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1789 <td class="left">Vector of 4 32-bit integer values.</td>
1790 </tr>
1791 <tr class="layout">
1792 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1793 <td class="left">Vector of 8 32-bit floating-point values.</td>
1794 </tr>
1795 <tr class="layout">
1796 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1797 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1798 </tr>
1799</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1800
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1801<p>Note that the code generator does not yet support large vector types to be
1802 used as function return types. The specific limit on how large a vector
1803 return type codegen can currently handle is target-dependent; currently it's
1804 often a few times longer than a hardware vector register.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1805
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1806</div>
1807
1808<!-- _______________________________________________________________________ -->
1809<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1810<div class="doc_text">
1811
1812<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1813<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1814 corresponds (for example) to the C notion of a forward declared structure
1815 type. In LLVM, opaque types can eventually be resolved to any type (not just
1816 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1817
1818<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1819<pre>
1820 opaque
1821</pre>
1822
1823<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1824<table class="layout">
1825 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1826 <td class="left"><tt>opaque</tt></td>
1827 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1828 </tr>
1829</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1830
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1831</div>
1832
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1833<!-- ======================================================================= -->
1834<div class="doc_subsection">
1835 <a name="t_uprefs">Type Up-references</a>
1836</div>
1837
1838<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1839
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1840<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1841<p>An "up reference" allows you to refer to a lexically enclosing type without
1842 requiring it to have a name. For instance, a structure declaration may
1843 contain a pointer to any of the types it is lexically a member of. Example
1844 of up references (with their equivalent as named type declarations)
1845 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1846
1847<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1848 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1849 { \2 }* %y = type { %y }*
1850 \1* %z = type %z*
1851</pre>
1852
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1853<p>An up reference is needed by the asmprinter for printing out cyclic types
1854 when there is no declared name for a type in the cycle. Because the
1855 asmprinter does not want to print out an infinite type string, it needs a
1856 syntax to handle recursive types that have no names (all names are optional
1857 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1858
1859<h5>Syntax:</h5>
1860<pre>
1861 \&lt;level&gt;
1862</pre>
1863
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1864<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]1865
1866<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1867<table class="layout">
1868 <tr class="layout">
1869 <td class="left"><tt>\1*</tt></td>
1870 <td class="left">Self-referential pointer.</td>
1871 </tr>
1872 <tr class="layout">
1873 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1874 <td class="left">Recursive structure where the upref refers to the out-most
1875 structure.</td>
1876 </tr>
1877</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1878
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1879</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1880
1881<!-- *********************************************************************** -->
1882<div class="doc_section"> <a name="constants">Constants</a> </div>
1883<!-- *********************************************************************** -->
1884
1885<div class="doc_text">
1886
1887<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1888 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1889
1890</div>
1891
1892<!-- ======================================================================= -->
1893<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1894
1895<div class="doc_text">
1896
1897<dl>
1898 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1899 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1900 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1901
1902 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1903 <dd>Standard integers (such as '4') are constants of
1904 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1905 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1906
1907 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1908 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1909 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1910 notation (see below). The assembler requires the exact decimal value of a
1911 floating-point constant. For example, the assembler accepts 1.25 but
1912 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1913 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1914
1915 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1916 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1917 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1918</dl>
1919
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1920<p>The one non-intuitive notation for constants is the hexadecimal form of
1921 floating point constants. For example, the form '<tt>double
1922 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1923 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1924 constants are required (and the only time that they are generated by the
1925 disassembler) is when a floating point constant must be emitted but it cannot
1926 be represented as a decimal floating point number in a reasonable number of
1927 digits. For example, NaN's, infinities, and other special values are
1928 represented in their IEEE hexadecimal format so that assembly and disassembly
1929 do not cause any bits to change in the constants.</p>
1930
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1931<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1932 represented using the 16-digit form shown above (which matches the IEEE754
1933 representation for double); float values must, however, be exactly
1934 representable as IEE754 single precision. Hexadecimal format is always used
1935 for long double, and there are three forms of long double. The 80-bit format
1936 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1937 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1938 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1939 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1940 currently supported target uses this format. Long doubles will only work if
1941 they match the long double format on your target. All hexadecimal formats
1942 are big-endian (sign bit at the left).</p>
1943
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1944</div>
1945
1946<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1947<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]1948<a name="aggregateconstants"></a> <!-- old anchor -->
1949<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1950</div>
1951
1952<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1953
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1954<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1955 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1956
1957<dl>
1958 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1959 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1960 type definitions (a comma separated list of elements, surrounded by braces
1961 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1962 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1963 Structure constants must have <a href="#t_struct">structure type</a>, and
1964 the number and types of elements must match those specified by the
1965 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1966
1967 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1968 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1969 definitions (a comma separated list of elements, surrounded by square
1970 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1971 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1972 the number and types of elements must match those specified by the
1973 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1974
1975 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1976 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1977 definitions (a comma separated list of elements, surrounded by
1978 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1979 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1980 have <a href="#t_vector">vector type</a>, and the number and types of
1981 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1982
1983 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1984 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1985 value to zero of <em>any</em> type, including scalar and aggregate types.
1986 This is often used to avoid having to print large zero initializers
1987 (e.g. for large arrays) and is always exactly equivalent to using explicit
1988 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1989
1990 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]1991 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1992 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1993 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1994 be interpreted as part of the instruction stream, metadata is a place to
1995 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1996</dl>
1997
1998</div>
1999
2000<!-- ======================================================================= -->
2001<div class="doc_subsection">
2002 <a name="globalconstants">Global Variable and Function Addresses</a>
2003</div>
2004
2005<div class="doc_text">
2006
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2007<p>The addresses of <a href="#globalvars">global variables</a>
2008 and <a href="#functionstructure">functions</a> are always implicitly valid
2009 (link-time) constants. These constants are explicitly referenced when
2010 the <a href="#identifiers">identifier for the global</a> is used and always
2011 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2012 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2013
2014<div class="doc_code">
2015<pre>
2016@X = global i32 17
2017@Y = global i32 42
2018@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2019</pre>
2020</div>
2021
2022</div>
2023
2024<!-- ======================================================================= -->
2025<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2026<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2027
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2028<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]2029 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2030 Undefined values may be of any type (other than label or void) and be used
2031 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2032
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2033<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2034 program is well defined no matter what value is used. This gives the
2035 compiler more freedom to optimize. Here are some examples of (potentially
2036 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2037
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2038
2039<div class="doc_code">
2040<pre>
2041 %A = add %X, undef
2042 %B = sub %X, undef
2043 %C = xor %X, undef
2044Safe:
2045 %A = undef
2046 %B = undef
2047 %C = undef
2048</pre>
2049</div>
2050
2051<p>This is safe because all of the output bits are affected by the undef bits.
2052Any output bit can have a zero or one depending on the input bits.</p>
2053
2054<div class="doc_code">
2055<pre>
2056 %A = or %X, undef
2057 %B = and %X, undef
2058Safe:
2059 %A = -1
2060 %B = 0
2061Unsafe:
2062 %A = undef
2063 %B = undef
2064</pre>
2065</div>
2066
2067<p>These logical operations have bits that are not always affected by the input.
2068For example, if "%X" has a zero bit, then the output of the 'and' operation will
2069always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2070such, it is unsafe to optimize or assume that the result of the and is undef.
2071However, it is safe to assume that all bits of the undef could be 0, and
2072optimize the and to 0. Likewise, it is safe to assume that all the bits of
2073the undef operand to the or could be set, allowing the or to be folded to
2074-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2075
2076<div class="doc_code">
2077<pre>
2078 %A = select undef, %X, %Y
2079 %B = select undef, 42, %Y
2080 %C = select %X, %Y, undef
2081Safe:
2082 %A = %X (or %Y)
2083 %B = 42 (or %Y)
2084 %C = %Y
2085Unsafe:
2086 %A = undef
2087 %B = undef
2088 %C = undef
2089</pre>
2090</div>
2091
2092<p>This set of examples show that undefined select (and conditional branch)
2093conditions can go "either way" but they have to come from one of the two
2094operands. In the %A example, if %X and %Y were both known to have a clear low
2095bit, then %A would have to have a cleared low bit. However, in the %C example,
2096the optimizer is allowed to assume that the undef operand could be the same as
2097%Y, allowing the whole select to be eliminated.</p>
2098
2099
2100<div class="doc_code">
2101<pre>
2102 %A = xor undef, undef
2103
2104 %B = undef
2105 %C = xor %B, %B
2106
2107 %D = undef
2108 %E = icmp lt %D, 4
2109 %F = icmp gte %D, 4
2110
2111Safe:
2112 %A = undef
2113 %B = undef
2114 %C = undef
2115 %D = undef
2116 %E = undef
2117 %F = undef
2118</pre>
2119</div>
2120
2121<p>This example points out that two undef operands are not necessarily the same.
2122This can be surprising to people (and also matches C semantics) where they
2123assume that "X^X" is always zero, even if X is undef. This isn't true for a
2124number of reasons, but the short answer is that an undef "variable" can
2125arbitrarily change its value over its "live range". This is true because the
2126"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2127logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2128so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2129to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2130would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2131
2132<div class="doc_code">
2133<pre>
2134 %A = fdiv undef, %X
2135 %B = fdiv %X, undef
2136Safe:
2137 %A = undef
2138b: unreachable
2139</pre>
2140</div>
2141
2142<p>These examples show the crucial difference between an <em>undefined
2143value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2144allowed to have an arbitrary bit-pattern. This means that the %A operation
2145can be constant folded to undef because the undef could be an SNaN, and fdiv is
2146not (currently) defined on SNaN's. However, in the second example, we can make
2147a more aggressive assumption: because the undef is allowed to be an arbitrary
2148value, 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]2149has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2150does not execute at all. This allows us to delete the divide and all code after
2151it: since the undefined operation "can't happen", the optimizer can assume that
2152it occurs in dead code.
2153</p>
2154
2155<div class="doc_code">
2156<pre>
2157a: store undef -> %X
2158b: store %X -> undef
2159Safe:
2160a: &lt;deleted&gt;
2161b: unreachable
2162</pre>
2163</div>
2164
2165<p>These examples reiterate the fdiv example: a store "of" an undefined value
2166can be assumed to not have any effect: we can assume that the value is
2167overwritten with bits that happen to match what was already there. However, a
2168store "to" an undefined location could clobber arbitrary memory, therefore, it
2169has undefined behavior.</p>
2170
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2171</div>
2172
2173<!-- ======================================================================= -->
2174<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2175</div>
2176
2177<div class="doc_text">
2178
2179<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2180 to be used as constants. Constant expressions may be of
2181 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2182 operation that does not have side effects (e.g. load and call are not
2183 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2184
2185<dl>
2186 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2187 <dd>Truncate a constant to another type. The bit size of CST must be larger
2188 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2189
2190 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2191 <dd>Zero extend a constant to another type. The bit size of CST must be
2192 smaller or equal to the bit size of TYPE. Both types must be
2193 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2194
2195 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2196 <dd>Sign extend a constant to another type. The bit size of CST must be
2197 smaller or equal to the bit size of TYPE. Both types must be
2198 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2199
2200 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2201 <dd>Truncate a floating point constant to another floating point type. The
2202 size of CST must be larger than the size of TYPE. Both types must be
2203 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2204
2205 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2206 <dd>Floating point extend a constant to another type. The size of CST must be
2207 smaller or equal to the size of TYPE. Both types must be floating
2208 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2209
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2210 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2211 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2212 constant. TYPE must be a scalar or vector integer type. CST must be of
2213 scalar or vector floating point type. Both CST and TYPE must be scalars,
2214 or vectors of the same number of elements. If the value won't fit in the
2215 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2216
2217 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2218 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2219 constant. TYPE must be a scalar or vector integer type. CST must be of
2220 scalar or vector floating point type. Both CST and TYPE must be scalars,
2221 or vectors of the same number of elements. If the value won't fit in the
2222 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2223
2224 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2225 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2226 constant. TYPE must be a scalar or vector floating point type. CST must be
2227 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2228 vectors of the same number of elements. If the value won't fit in the
2229 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2230
2231 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2232 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2233 constant. TYPE must be a scalar or vector floating point type. CST must be
2234 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2235 vectors of the same number of elements. If the value won't fit in the
2236 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2237
2238 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2239 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2240 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2241 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2242 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2243
2244 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2245 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2246 type. CST must be of integer type. The CST value is zero extended,
2247 truncated, or unchanged to make it fit in a pointer size. This one is
2248 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2249
2250 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2251 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2252 are the same as those for the <a href="#i_bitcast">bitcast
2253 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2254
2255 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2256 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2257 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2258 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2259 instruction, the index list may have zero or more indexes, which are
2260 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2261
2262 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2263 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2264
2265 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2266 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2267
2268 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2269 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2270
2271 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2272 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2273 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2274
2275 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2276 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2277 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2278
2279 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2280 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2281 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2282
2283 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2284 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2285 be any of the <a href="#binaryops">binary</a>
2286 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2287 on operands are the same as those for the corresponding instruction
2288 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2289</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2290
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2291</div>
2292
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2293<!-- ======================================================================= -->
2294<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2295</div>
2296
2297<div class="doc_text">
2298
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2299<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2300 stream without affecting the behaviour of the program. There are two
2301 metadata primitives, strings and nodes. All metadata has the
2302 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2303 point ('<tt>!</tt>').</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2304
2305<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2306 any character by escaping non-printable characters with "\xx" where "xx" is
2307 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2308
2309<p>Metadata nodes are represented with notation similar to structure constants
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2310 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2311 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2312 10}</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2313
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2314<p>A metadata node will attempt to track changes to the values it holds. In the
2315 event that a value is deleted, it will be replaced with a typeless
2316 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2317
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2318<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2319 the program that isn't available in the instructions, or that isn't easily
2320 computable. Similarly, the code generator may expect a certain metadata
2321 format to be used to express debugging information.</p>
2322
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2323</div>
2324
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2325<!-- *********************************************************************** -->
2326<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2327<!-- *********************************************************************** -->
2328
2329<!-- ======================================================================= -->
2330<div class="doc_subsection">
2331<a name="inlineasm">Inline Assembler Expressions</a>
2332</div>
2333
2334<div class="doc_text">
2335
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2336<p>LLVM supports inline assembler expressions (as opposed
2337 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2338 a special value. This value represents the inline assembler as a string
2339 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2340 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2341 expression has side effects, and a flag indicating whether the function
2342 containing the asm needs to align its stack conservatively. An example
2343 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2344
2345<div class="doc_code">
2346<pre>
2347i32 (i32) asm "bswap $0", "=r,r"
2348</pre>
2349</div>
2350
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2351<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2352 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2353 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2354
2355<div class="doc_code">
2356<pre>
2357%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2358</pre>
2359</div>
2360
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2361<p>Inline asms with side effects not visible in the constraint list must be
2362 marked as having side effects. This is done through the use of the
2363 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2364
2365<div class="doc_code">
2366<pre>
2367call void asm sideeffect "eieio", ""()
2368</pre>
2369</div>
2370
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2371<p>In some cases inline asms will contain code that will not work unless the
2372 stack is aligned in some way, such as calls or SSE instructions on x86,
2373 yet will not contain code that does that alignment within the asm.
2374 The compiler should make conservative assumptions about what the asm might
2375 contain and should generate its usual stack alignment code in the prologue
2376 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2377
2378<div class="doc_code">
2379<pre>
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2380call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2381</pre>
2382</div>
2383
2384<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2385 first.</p>
2386
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2387<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2388 documented here. Constraints on what can be done (e.g. duplication, moving,
2389 etc need to be documented). This is probably best done by reference to
2390 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2391
2392</div>
2393
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2394
2395<!-- *********************************************************************** -->
2396<div class="doc_section">
2397 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2398</div>
2399<!-- *********************************************************************** -->
2400
2401<p>LLVM has a number of "magic" global variables that contain data that affect
2402code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2403of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2404section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2405by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2406
2407<!-- ======================================================================= -->
2408<div class="doc_subsection">
2409<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2410</div>
2411
2412<div class="doc_text">
2413
2414<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2415href="#linkage_appending">appending linkage</a>. This array contains a list of
2416pointers to global variables and functions which may optionally have a pointer
2417cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2418
2419<pre>
2420 @X = global i8 4
2421 @Y = global i32 123
2422
2423 @llvm.used = appending global [2 x i8*] [
2424 i8* @X,
2425 i8* bitcast (i32* @Y to i8*)
2426 ], section "llvm.metadata"
2427</pre>
2428
2429<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2430compiler, assembler, and linker are required to treat the symbol as if there is
2431a reference to the global that it cannot see. For example, if a variable has
2432internal linkage and no references other than that from the <tt>@llvm.used</tt>
2433list, it cannot be deleted. This is commonly used to represent references from
2434inline asms and other things the compiler cannot "see", and corresponds to
2435"attribute((used))" in GNU C.</p>
2436
2437<p>On some targets, the code generator must emit a directive to the assembler or
2438object file to prevent the assembler and linker from molesting the symbol.</p>
2439
2440</div>
2441
2442<!-- ======================================================================= -->
2443<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2444<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2445</div>
2446
2447<div class="doc_text">
2448
2449<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2450<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2451touching the symbol. On targets that support it, this allows an intelligent
2452linker to optimize references to the symbol without being impeded as it would be
2453by <tt>@llvm.used</tt>.</p>
2454
2455<p>This is a rare construct that should only be used in rare circumstances, and
2456should not be exposed to source languages.</p>
2457
2458</div>
2459
2460<!-- ======================================================================= -->
2461<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2462<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2463</div>
2464
2465<div class="doc_text">
2466
2467<p>TODO: Describe this.</p>
2468
2469</div>
2470
2471<!-- ======================================================================= -->
2472<div class="doc_subsection">
2473<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2474</div>
2475
2476<div class="doc_text">
2477
2478<p>TODO: Describe this.</p>
2479
2480</div>
2481
2482
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2483<!-- *********************************************************************** -->
2484<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2485<!-- *********************************************************************** -->
2486
2487<div class="doc_text">
2488
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2489<p>The LLVM instruction set consists of several different classifications of
2490 instructions: <a href="#terminators">terminator
2491 instructions</a>, <a href="#binaryops">binary instructions</a>,
2492 <a href="#bitwiseops">bitwise binary instructions</a>,
2493 <a href="#memoryops">memory instructions</a>, and
2494 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2495
2496</div>
2497
2498<!-- ======================================================================= -->
2499<div class="doc_subsection"> <a name="terminators">Terminator
2500Instructions</a> </div>
2501
2502<div class="doc_text">
2503
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2504<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2505 in a program ends with a "Terminator" instruction, which indicates which
2506 block should be executed after the current block is finished. These
2507 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2508 control flow, not values (the one exception being the
2509 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2510
2511<p>There are six different terminator instructions: the
2512 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2513 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2514 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame^]2515 '<a href="#i_indbr">'<tt>indbr</tt>' Instruction, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2516 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2517 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2518 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2519
2520</div>
2521
2522<!-- _______________________________________________________________________ -->
2523<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2524Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2525
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2526<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2527
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2528<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2529<pre>
2530 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]2531 ret void <i>; Return from void function</i>
2532</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2533
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2534<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2535<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2536 a value) from a function back to the caller.</p>
2537
2538<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2539 value and then causes control flow, and one that just causes control flow to
2540 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2541
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2542<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2543<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2544 return value. The type of the return value must be a
2545 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2546
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2547<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2548 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2549 value or a return value with a type that does not match its type, or if it
2550 has a void return type and contains a '<tt>ret</tt>' instruction with a
2551 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2552
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2553<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2554<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2555 the calling function's context. If the caller is a
2556 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2557 instruction after the call. If the caller was an
2558 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2559 the beginning of the "normal" destination block. If the instruction returns
2560 a value, that value shall set the call or invoke instruction's return
2561 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2562
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2563<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2564<pre>
2565 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2566 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2567 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]2568</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2569
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2570<p>Note that the code generator does not yet fully support large
2571 return values. The specific sizes that are currently supported are
2572 dependent on the target. For integers, on 32-bit targets the limit
2573 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2574 For aggregate types, the current limits are dependent on the element
2575 types; for example targets are often limited to 2 total integer
2576 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2577
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2578</div>
2579<!-- _______________________________________________________________________ -->
2580<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2581
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2582<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2583
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2584<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2585<pre>
2586 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]2587</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2588
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2589<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2590<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2591 different basic block in the current function. There are two forms of this
2592 instruction, corresponding to a conditional branch and an unconditional
2593 branch.</p>
2594
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2595<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2596<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2597 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2598 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2599 target.</p>
2600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2601<h5>Semantics:</h5>
2602<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2603 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2604 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2605 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2606
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2607<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2608<pre>
2609Test:
2610 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2611 br i1 %cond, label %IfEqual, label %IfUnequal
2612IfEqual:
2613 <a href="#i_ret">ret</a> i32 1
2614IfUnequal:
2615 <a href="#i_ret">ret</a> i32 0
2616</pre>
2617
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2618</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2619
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2620<!-- _______________________________________________________________________ -->
2621<div class="doc_subsubsection">
2622 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2623</div>
2624
2625<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2626
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2627<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2628<pre>
2629 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2630</pre>
2631
2632<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2633<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]2634 several different places. It is a generalization of the '<tt>br</tt>'
2635 instruction, allowing a branch to occur to one of many possible
2636 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2637
2638<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2639<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2640 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2641 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2642 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2643
2644<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2645<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2646 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2647 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2648 transferred to the corresponding destination; otherwise, control flow is
2649 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2650
2651<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2652<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2653 <tt>switch</tt> instruction, this instruction may be code generated in
2654 different ways. For example, it could be generated as a series of chained
2655 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2656
2657<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2658<pre>
2659 <i>; Emulate a conditional br instruction</i>
2660 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2661 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2662
2663 <i>; Emulate an unconditional br instruction</i>
2664 switch i32 0, label %dest [ ]
2665
2666 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2667 switch i32 %val, label %otherwise [ i32 0, label %onzero
2668 i32 1, label %onone
2669 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2670</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2671
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2672</div>
2673
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame^]2674
2675<!-- _______________________________________________________________________ -->
2676<div class="doc_subsubsection">
2677 <a name="i_indbr">'<tt>indbr</tt>' Instruction</a>
2678</div>
2679
2680<div class="doc_text">
2681
2682<h5>Syntax:</h5>
2683<pre>
2684 indbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
2685</pre>
2686
2687<h5>Overview:</h5>
2688
2689<p>The '<tt>indbr</tt>' instruction implements an indirect branch to a label
2690 within the current function, whose address is specified by
2691 "<tt>address</tt>".</p>
2692
2693<h5>Arguments:</h5>
2694
2695<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2696 rest of the arguments indicate the full set of possible destinations that the
2697 address may point to. Blocks are allowed to occur multiple times in the
2698 destination list, though this isn't particularly useful.</p>
2699
2700<p>This destination list is required so that dataflow analysis has an accurate
2701 understanding of the CFG.</p>
2702
2703<h5>Semantics:</h5>
2704
2705<p>Control transfers to the block specified in the address argument. All
2706 possible destination blocks must be listed in the label list, otherwise this
2707 instruction has undefined behavior. This implies that jumps to labels
2708 defined in other functions have undefined behavior as well.</p>
2709
2710<h5>Implementation:</h5>
2711
2712<p>This is typically implemented with a jump through a register.</p>
2713
2714<h5>Example:</h5>
2715<pre>
2716 switch i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
2717</pre>
2718
2719</div>
2720
2721
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2722<!-- _______________________________________________________________________ -->
2723<div class="doc_subsubsection">
2724 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2725</div>
2726
2727<div class="doc_text">
2728
2729<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2730<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2731 &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]2732 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2733</pre>
2734
2735<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2736<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2737 function, with the possibility of control flow transfer to either the
2738 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2739 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2740 control flow will return to the "normal" label. If the callee (or any
2741 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2742 instruction, control is interrupted and continued at the dynamically nearest
2743 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2744
2745<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2746<p>This instruction requires several arguments:</p>
2747
2748<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2749 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2750 convention</a> the call should use. If none is specified, the call
2751 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2752
2753 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2754 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2755 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2756
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2757 <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]2758 function value being invoked. In most cases, this is a direct function
2759 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2760 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2761
2762 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2763 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2764
2765 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2766 signature argument types. If the function signature indicates the
2767 function accepts a variable number of arguments, the extra arguments can
2768 be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2769
2770 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2771 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2772
2773 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2774 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2775
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2776 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2777 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2778 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2779</ol>
2780
2781<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2782<p>This instruction is designed to operate as a standard
2783 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2784 primary difference is that it establishes an association with a label, which
2785 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2786
2787<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2788 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2789 exception. Additionally, this is important for implementation of
2790 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2791
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2792<p>For the purposes of the SSA form, the definition of the value returned by the
2793 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2794 block to the "normal" label. If the callee unwinds then no return value is
2795 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2796
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2797<h5>Example:</h5>
2798<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2799 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2800 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2801 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2802 unwind label %TestCleanup <i>; {i32}:retval set</i>
2803</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2804
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2805</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2806
2807<!-- _______________________________________________________________________ -->
2808
2809<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2810Instruction</a> </div>
2811
2812<div class="doc_text">
2813
2814<h5>Syntax:</h5>
2815<pre>
2816 unwind
2817</pre>
2818
2819<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2820<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2821 at the first callee in the dynamic call stack which used
2822 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2823 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2824
2825<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2826<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2827 immediately halt. The dynamic call stack is then searched for the
2828 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2829 Once found, execution continues at the "exceptional" destination block
2830 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2831 instruction in the dynamic call chain, undefined behavior results.</p>
2832
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2833</div>
2834
2835<!-- _______________________________________________________________________ -->
2836
2837<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2838Instruction</a> </div>
2839
2840<div class="doc_text">
2841
2842<h5>Syntax:</h5>
2843<pre>
2844 unreachable
2845</pre>
2846
2847<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2848<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2849 instruction is used to inform the optimizer that a particular portion of the
2850 code is not reachable. This can be used to indicate that the code after a
2851 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2852
2853<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2854<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2855
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2856</div>
2857
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2858<!-- ======================================================================= -->
2859<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2860
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2861<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2862
2863<p>Binary operators are used to do most of the computation in a program. They
2864 require two operands of the same type, execute an operation on them, and
2865 produce a single value. The operands might represent multiple data, as is
2866 the case with the <a href="#t_vector">vector</a> data type. The result value
2867 has the same type as its operands.</p>
2868
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2869<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2870
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2871</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2872
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2873<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2874<div class="doc_subsubsection">
2875 <a name="i_add">'<tt>add</tt>' Instruction</a>
2876</div>
2877
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2878<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2879
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2880<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2881<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2882 &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]2883 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2884 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2885 &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]2886</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2887
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2888<h5>Overview:</h5>
2889<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2890
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2891<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2892<p>The two arguments to the '<tt>add</tt>' instruction must
2893 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2894 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2895
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2896<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2897<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2898
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2899<p>If the sum has unsigned overflow, the result returned is the mathematical
2900 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]2901
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2902<p>Because LLVM integers use a two's complement representation, this instruction
2903 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2904
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2905<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2906 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2907 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2908 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2909
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2910<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2911<pre>
2912 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2913</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2914
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2915</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2916
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2917<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2918<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2919 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2920</div>
2921
2922<div class="doc_text">
2923
2924<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2925<pre>
2926 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2927</pre>
2928
2929<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2930<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2931
2932<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2933<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2934 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2935 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2936
2937<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2938<p>The value produced is the floating point sum of the two operands.</p>
2939
2940<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2941<pre>
2942 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2943</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2944
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2945</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2946
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2947<!-- _______________________________________________________________________ -->
2948<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2949 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2950</div>
2951
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2952<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2953
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2954<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2955<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2956 &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]2957 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2958 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2959 &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]2960</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2961
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2962<h5>Overview:</h5>
2963<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2964 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2965
2966<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2967 '<tt>neg</tt>' instruction present in most other intermediate
2968 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2969
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2970<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2971<p>The two arguments to the '<tt>sub</tt>' instruction must
2972 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2973 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2974
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2975<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2976<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2977
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2978<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2979 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2980 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2981
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2982<p>Because LLVM integers use a two's complement representation, this instruction
2983 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2984
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2985<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2986 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2987 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2988 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2989
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2990<h5>Example:</h5>
2991<pre>
2992 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2993 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2994</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2995
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2996</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2997
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2998<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2999<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3000 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3001</div>
3002
3003<div class="doc_text">
3004
3005<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3006<pre>
3007 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3008</pre>
3009
3010<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3011<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3012 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3013
3014<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3015 '<tt>fneg</tt>' instruction present in most other intermediate
3016 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3017
3018<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]3019<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3020 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3021 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3022
3023<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3024<p>The value produced is the floating point difference of the two operands.</p>
3025
3026<h5>Example:</h5>
3027<pre>
3028 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3029 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3030</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3031
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3032</div>
3033
3034<!-- _______________________________________________________________________ -->
3035<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3036 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3037</div>
3038
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3039<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3040
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3041<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3042<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3043 &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]3044 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3045 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3046 &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]3047</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3048
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3049<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3050<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3051
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3052<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3053<p>The two arguments to the '<tt>mul</tt>' instruction must
3054 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3055 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3056
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3057<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3058<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3059
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3060<p>If the result of the multiplication has unsigned overflow, the result
3061 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3062 width of the result.</p>
3063
3064<p>Because LLVM integers use a two's complement representation, and the result
3065 is the same width as the operands, this instruction returns the correct
3066 result for both signed and unsigned integers. If a full product
3067 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3068 be sign-extended or zero-extended as appropriate to the width of the full
3069 product.</p>
3070
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3071<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3072 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3073 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3074 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3075
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3076<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3077<pre>
3078 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3079</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3080
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3081</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3082
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3083<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3084<div class="doc_subsubsection">
3085 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3086</div>
3087
3088<div class="doc_text">
3089
3090<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3091<pre>
3092 &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]3093</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3094
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3095<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3096<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3097
3098<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3099<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3100 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3101 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3102
3103<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3104<p>The value produced is the floating point product of the two operands.</p>
3105
3106<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3107<pre>
3108 &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]3109</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3110
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3111</div>
3112
3113<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3114<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3115</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3116
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3117<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3118
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3119<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3120<pre>
3121 &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]3122</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3123
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3124<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3125<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3126
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3127<h5>Arguments:</h5>
3128<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3129 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3130 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3131
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3132<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3133<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3134
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3135<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3136 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3137
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3138<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3139
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3140<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3141<pre>
3142 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3143</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3144
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3145</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3146
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3147<!-- _______________________________________________________________________ -->
3148<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3149</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3150
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3151<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3152
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3153<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3154<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3155 &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]3156 &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]3157</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3158
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3159<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3160<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3161
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3162<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3163<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3164 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3165 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3166
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3167<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3168<p>The value produced is the signed integer quotient of the two operands rounded
3169 towards zero.</p>
3170
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3171<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3172 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3173
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3174<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3175 undefined behavior; this is a rare case, but can occur, for example, by doing
3176 a 32-bit division of -2147483648 by -1.</p>
3177
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3178<p>If the <tt>exact</tt> keyword is present, the result value of the
3179 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3180 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3181
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3182<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3183<pre>
3184 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3185</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3186
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3187</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3188
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3189<!-- _______________________________________________________________________ -->
3190<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3191Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3192
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3193<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3194
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3195<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3196<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3197 &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]3198</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3199
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3200<h5>Overview:</h5>
3201<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3202
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3203<h5>Arguments:</h5>
3204<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3205 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3206 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3207
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3208<h5>Semantics:</h5>
3209<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3211<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3212<pre>
3213 &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]3214</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3215
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3216</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3217
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3218<!-- _______________________________________________________________________ -->
3219<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3220</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3221
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3222<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3223
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3224<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3225<pre>
3226 &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]3227</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3228
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3229<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3230<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3231 division of its two arguments.</p>
3232
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3233<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3234<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3235 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3236 values. Both arguments must have identical types.</p>
3237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3238<h5>Semantics:</h5>
3239<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3240 This instruction always performs an unsigned division to get the
3241 remainder.</p>
3242
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3243<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3244 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3245
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3246<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3247
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3248<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3249<pre>
3250 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3251</pre>
3252
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_srem">'<tt>srem</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>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3264 &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]3265</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3266
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3267<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3268<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3269 division of its two operands. This instruction can also take
3270 <a href="#t_vector">vector</a> versions of the values in which case the
3271 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3272
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3273<h5>Arguments:</h5>
3274<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3275 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3276 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>
3279<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3280 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3281 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3282 a value. For more information about the difference,
3283 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3284 Math Forum</a>. For a table of how this is implemented in various languages,
3285 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3286 Wikipedia: modulo operation</a>.</p>
3287
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3288<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3289 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3290
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3291<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3292 Overflow also leads to undefined behavior; this is a rare case, but can
3293 occur, for example, by taking the remainder of a 32-bit division of
3294 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3295 lets srem be implemented using instructions that return both the result of
3296 the division and the remainder.)</p>
3297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3298<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3299<pre>
3300 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3301</pre>
3302
3303</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3304
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3305<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3306<div class="doc_subsubsection">
3307 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3308
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3309<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3310
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3311<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3312<pre>
3313 &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]3314</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3315
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3316<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3317<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3318 its two operands.</p>
3319
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3320<h5>Arguments:</h5>
3321<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3322 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3323 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3324
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3325<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3326<p>This instruction returns the <i>remainder</i> of a division. The remainder
3327 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3328
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3329<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3330<pre>
3331 &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]3332</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3333
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3334</div>
3335
3336<!-- ======================================================================= -->
3337<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3338Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3339
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3340<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3341
3342<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3343 program. They are generally very efficient instructions and can commonly be
3344 strength reduced from other instructions. They require two operands of the
3345 same type, execute an operation on them, and produce a single value. The
3346 resulting value is the same type as its operands.</p>
3347
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3348</div>
3349
3350<!-- _______________________________________________________________________ -->
3351<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3352Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3353
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3354<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3355
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3356<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3357<pre>
3358 &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]3359</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3360
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3361<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3362<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3363 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3364
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3365<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3366<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3367 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3368 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3369
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3370<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3371<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3372 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3373 is (statically or dynamically) negative or equal to or larger than the number
3374 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3375 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3376 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3377
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3378<h5>Example:</h5>
3379<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3380 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3381 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3382 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3383 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3384 &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]3385</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3386
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3387</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3388
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3389<!-- _______________________________________________________________________ -->
3390<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3391Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3392
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3393<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3394
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3395<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3396<pre>
3397 &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]3398</pre>
3399
3400<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3401<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3402 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3403
3404<h5>Arguments:</h5>
3405<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3406 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3407 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3408
3409<h5>Semantics:</h5>
3410<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3411 significant bits of the result will be filled with zero bits after the shift.
3412 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3413 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3414 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3415 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3416
3417<h5>Example:</h5>
3418<pre>
3419 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3420 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3421 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3422 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3423 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3424 &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]3425</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3426
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3427</div>
3428
3429<!-- _______________________________________________________________________ -->
3430<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3431Instruction</a> </div>
3432<div class="doc_text">
3433
3434<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3435<pre>
3436 &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]3437</pre>
3438
3439<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3440<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3441 operand shifted to the right a specified number of bits with sign
3442 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3443
3444<h5>Arguments:</h5>
3445<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3446 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3447 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3448
3449<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3450<p>This instruction always performs an arithmetic shift right operation, The
3451 most significant bits of the result will be filled with the sign bit
3452 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3453 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3454 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3455 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3456
3457<h5>Example:</h5>
3458<pre>
3459 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3460 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3461 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3462 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3463 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3464 &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]3465</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3466
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3467</div>
3468
3469<!-- _______________________________________________________________________ -->
3470<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3471Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3472
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3473<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3474
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3475<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3476<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3477 &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]3478</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3479
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3480<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3481<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3482 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3483
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3484<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3485<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3486 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3487 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3488
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3489<h5>Semantics:</h5>
3490<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3491
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3492<table border="1" cellspacing="0" cellpadding="4">
3493 <tbody>
3494 <tr>
3495 <td>In0</td>
3496 <td>In1</td>
3497 <td>Out</td>
3498 </tr>
3499 <tr>
3500 <td>0</td>
3501 <td>0</td>
3502 <td>0</td>
3503 </tr>
3504 <tr>
3505 <td>0</td>
3506 <td>1</td>
3507 <td>0</td>
3508 </tr>
3509 <tr>
3510 <td>1</td>
3511 <td>0</td>
3512 <td>0</td>
3513 </tr>
3514 <tr>
3515 <td>1</td>
3516 <td>1</td>
3517 <td>1</td>
3518 </tr>
3519 </tbody>
3520</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3521
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3522<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3523<pre>
3524 &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]3525 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3526 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3527</pre>
3528</div>
3529<!-- _______________________________________________________________________ -->
3530<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3531
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3532<div class="doc_text">
3533
3534<h5>Syntax:</h5>
3535<pre>
3536 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3537</pre>
3538
3539<h5>Overview:</h5>
3540<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3541 two operands.</p>
3542
3543<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3544<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3545 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3546 values. Both arguments must have identical types.</p>
3547
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3548<h5>Semantics:</h5>
3549<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3550
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3551<table border="1" cellspacing="0" cellpadding="4">
3552 <tbody>
3553 <tr>
3554 <td>In0</td>
3555 <td>In1</td>
3556 <td>Out</td>
3557 </tr>
3558 <tr>
3559 <td>0</td>
3560 <td>0</td>
3561 <td>0</td>
3562 </tr>
3563 <tr>
3564 <td>0</td>
3565 <td>1</td>
3566 <td>1</td>
3567 </tr>
3568 <tr>
3569 <td>1</td>
3570 <td>0</td>
3571 <td>1</td>
3572 </tr>
3573 <tr>
3574 <td>1</td>
3575 <td>1</td>
3576 <td>1</td>
3577 </tr>
3578 </tbody>
3579</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3580
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3581<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3582<pre>
3583 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3584 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3585 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3586</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3587
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3588</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3590<!-- _______________________________________________________________________ -->
3591<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3592Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3593
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3594<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3595
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3596<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3597<pre>
3598 &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]3599</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3601<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3602<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3603 its two operands. The <tt>xor</tt> is used to implement the "one's
3604 complement" operation, which is the "~" operator in C.</p>
3605
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3606<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3607<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3608 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3609 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3610
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3611<h5>Semantics:</h5>
3612<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3613
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3614<table border="1" cellspacing="0" cellpadding="4">
3615 <tbody>
3616 <tr>
3617 <td>In0</td>
3618 <td>In1</td>
3619 <td>Out</td>
3620 </tr>
3621 <tr>
3622 <td>0</td>
3623 <td>0</td>
3624 <td>0</td>
3625 </tr>
3626 <tr>
3627 <td>0</td>
3628 <td>1</td>
3629 <td>1</td>
3630 </tr>
3631 <tr>
3632 <td>1</td>
3633 <td>0</td>
3634 <td>1</td>
3635 </tr>
3636 <tr>
3637 <td>1</td>
3638 <td>1</td>
3639 <td>0</td>
3640 </tr>
3641 </tbody>
3642</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3643
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3644<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3645<pre>
3646 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3647 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3648 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3649 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3650</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3651
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3652</div>
3653
3654<!-- ======================================================================= -->
3655<div class="doc_subsection">
3656 <a name="vectorops">Vector Operations</a>
3657</div>
3658
3659<div class="doc_text">
3660
3661<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3662 target-independent manner. These instructions cover the element-access and
3663 vector-specific operations needed to process vectors effectively. While LLVM
3664 does directly support these vector operations, many sophisticated algorithms
3665 will want to use target-specific intrinsics to take full advantage of a
3666 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3667
3668</div>
3669
3670<!-- _______________________________________________________________________ -->
3671<div class="doc_subsubsection">
3672 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3673</div>
3674
3675<div class="doc_text">
3676
3677<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3678<pre>
3679 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3680</pre>
3681
3682<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3683<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3684 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3685
3686
3687<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3688<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3689 of <a href="#t_vector">vector</a> type. The second operand is an index
3690 indicating the position from which to extract the element. The index may be
3691 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3692
3693<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3694<p>The result is a scalar of the same type as the element type of
3695 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3696 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3697 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3698
3699<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3700<pre>
3701 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3702</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3703
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3704</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3705
3706<!-- _______________________________________________________________________ -->
3707<div class="doc_subsubsection">
3708 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3709</div>
3710
3711<div class="doc_text">
3712
3713<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3714<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3715 &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]3716</pre>
3717
3718<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3719<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3720 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3721
3722<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3723<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3724 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3725 whose type must equal the element type of the first operand. The third
3726 operand is an index indicating the position at which to insert the value.
3727 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3728
3729<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3730<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3731 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3732 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3733 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3734
3735<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3736<pre>
3737 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3738</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3739
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3740</div>
3741
3742<!-- _______________________________________________________________________ -->
3743<div class="doc_subsubsection">
3744 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3745</div>
3746
3747<div class="doc_text">
3748
3749<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3750<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3751 &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]3752</pre>
3753
3754<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3755<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3756 from two input vectors, returning a vector with the same element type as the
3757 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3758
3759<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3760<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3761 with types that match each other. The third argument is a shuffle mask whose
3762 element type is always 'i32'. The result of the instruction is a vector
3763 whose length is the same as the shuffle mask and whose element type is the
3764 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3765
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3766<p>The shuffle mask operand is required to be a constant vector with either
3767 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3768
3769<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3770<p>The elements of the two input vectors are numbered from left to right across
3771 both of the vectors. The shuffle mask operand specifies, for each element of
3772 the result vector, which element of the two input vectors the result element
3773 gets. The element selector may be undef (meaning "don't care") and the
3774 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3775
3776<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3777<pre>
3778 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3779 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3780 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3781 &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.
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3782 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3783 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3784 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3785 &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]3786</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3787
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3788</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3789
3790<!-- ======================================================================= -->
3791<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3792 <a name="aggregateops">Aggregate Operations</a>
3793</div>
3794
3795<div class="doc_text">
3796
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3797<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3798
3799</div>
3800
3801<!-- _______________________________________________________________________ -->
3802<div class="doc_subsubsection">
3803 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3804</div>
3805
3806<div class="doc_text">
3807
3808<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3809<pre>
3810 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3811</pre>
3812
3813<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3814<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3815 or array element from an aggregate value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3816
3817<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3818<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3819 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3820 operands are constant indices to specify which value to extract in a similar
3821 manner as indices in a
3822 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3823
3824<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3825<p>The result is the value at the position in the aggregate specified by the
3826 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3827
3828<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3829<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3830 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3831</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3832
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3833</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3834
3835<!-- _______________________________________________________________________ -->
3836<div class="doc_subsubsection">
3837 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3838</div>
3839
3840<div class="doc_text">
3841
3842<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3843<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3844 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3845</pre>
3846
3847<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3848<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3849 array element in an aggregate.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3850
3851
3852<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3853<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3854 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3855 second operand is a first-class value to insert. The following operands are
3856 constant indices indicating the position at which to insert the value in a
3857 similar manner as indices in a
3858 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3859 value to insert must have the same type as the value identified by the
3860 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3861
3862<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3863<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3864 that of <tt>val</tt> except that the value at the position specified by the
3865 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3866
3867<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3868<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3869 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3870</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3871
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3872</div>
3873
3874
3875<!-- ======================================================================= -->
3876<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3877 <a name="memoryops">Memory Access and Addressing Operations</a>
3878</div>
3879
3880<div class="doc_text">
3881
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3882<p>A key design point of an SSA-based representation is how it represents
3883 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]3884 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3885 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3886
3887</div>
3888
3889<!-- _______________________________________________________________________ -->
3890<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3891 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3892</div>
3893
3894<div class="doc_text">
3895
3896<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3897<pre>
3898 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3899</pre>
3900
3901<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3902<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3903 currently executing function, to be automatically released when this function
3904 returns to its caller. The object is always allocated in the generic address
3905 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3906
3907<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3908<p>The '<tt>alloca</tt>' instruction
3909 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3910 runtime stack, returning a pointer of the appropriate type to the program.
3911 If "NumElements" is specified, it is the number of elements allocated,
3912 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3913 specified, the value result of the allocation is guaranteed to be aligned to
3914 at least that boundary. If not specified, or if zero, the target can choose
3915 to align the allocation on any convenient boundary compatible with the
3916 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3917
3918<p>'<tt>type</tt>' may be any sized type.</p>
3919
3920<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3921<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3922 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3923 memory is automatically released when the function returns. The
3924 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3925 variables that must have an address available. When the function returns
3926 (either with the <tt><a href="#i_ret">ret</a></tt>
3927 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3928 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3929
3930<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3931<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3932 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3933 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3934 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3935 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3936</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3937
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3938</div>
3939
3940<!-- _______________________________________________________________________ -->
3941<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3942Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3943
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3944<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3945
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3946<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3947<pre>
3948 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3949 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3950</pre>
3951
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3952<h5>Overview:</h5>
3953<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3954
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3955<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3956<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3957 from which to load. The pointer must point to
3958 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3959 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3960 number or order of execution of this <tt>load</tt> with other
3961 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3962 instructions. </p>
3963
3964<p>The optional constant "align" argument specifies the alignment of the
3965 operation (that is, the alignment of the memory address). A value of 0 or an
3966 omitted "align" argument means that the operation has the preferential
3967 alignment for the target. It is the responsibility of the code emitter to
3968 ensure that the alignment information is correct. Overestimating the
3969 alignment results in an undefined behavior. Underestimating the alignment may
3970 produce less efficient code. An alignment of 1 is always safe.</p>
3971
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3972<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3973<p>The location of memory pointed to is loaded. If the value being loaded is of
3974 scalar type then the number of bytes read does not exceed the minimum number
3975 of bytes needed to hold all bits of the type. For example, loading an
3976 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3977 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3978 is undefined if the value was not originally written using a store of the
3979 same type.</p>
3980
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3981<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3982<pre>
3983 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3984 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3985 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3986</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3987
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3988</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3989
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3990<!-- _______________________________________________________________________ -->
3991<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3992Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3993
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3994<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3995
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3996<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3997<pre>
3998 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3999 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
4000</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4001
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4002<h5>Overview:</h5>
4003<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4004
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4005<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4006<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4007 and an address at which to store it. The type of the
4008 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4009 the <a href="#t_firstclass">first class</a> type of the
4010 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4011 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4012 or order of execution of this <tt>store</tt> with other
4013 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4014 instructions.</p>
4015
4016<p>The optional constant "align" argument specifies the alignment of the
4017 operation (that is, the alignment of the memory address). A value of 0 or an
4018 omitted "align" argument means that the operation has the preferential
4019 alignment for the target. It is the responsibility of the code emitter to
4020 ensure that the alignment information is correct. Overestimating the
4021 alignment results in an undefined behavior. Underestimating the alignment may
4022 produce less efficient code. An alignment of 1 is always safe.</p>
4023
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4024<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4025<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4026 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4027 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4028 does not exceed the minimum number of bytes needed to hold all bits of the
4029 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4030 writing a value of a type like <tt>i20</tt> with a size that is not an
4031 integral number of bytes, it is unspecified what happens to the extra bits
4032 that do not belong to the type, but they will typically be overwritten.</p>
4033
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4034<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4035<pre>
4036 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4037 store i32 3, i32* %ptr <i>; yields {void}</i>
4038 %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]4039</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4040
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4041</div>
4042
4043<!-- _______________________________________________________________________ -->
4044<div class="doc_subsubsection">
4045 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4046</div>
4047
4048<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4049
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4050<h5>Syntax:</h5>
4051<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4052 &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]4053 &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]4054</pre>
4055
4056<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4057<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4058 subelement of an aggregate data structure. It performs address calculation
4059 only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4060
4061<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4062<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4063 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4064 elements of the aggregate object are indexed. The interpretation of each
4065 index is dependent on the type being indexed into. The first index always
4066 indexes the pointer value given as the first argument, the second index
4067 indexes a value of the type pointed to (not necessarily the value directly
4068 pointed to, since the first index can be non-zero), etc. The first type
4069 indexed into must be a pointer value, subsequent types can be arrays, vectors
4070 and structs. Note that subsequent types being indexed into can never be
4071 pointers, since that would require loading the pointer before continuing
4072 calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4073
4074<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4075 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4076 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4077 vector, integers of any width are allowed, and they are not required to be
4078 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4079
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4080<p>For example, let's consider a C code fragment and how it gets compiled to
4081 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4082
4083<div class="doc_code">
4084<pre>
4085struct RT {
4086 char A;
4087 int B[10][20];
4088 char C;
4089};
4090struct ST {
4091 int X;
4092 double Y;
4093 struct RT Z;
4094};
4095
4096int *foo(struct ST *s) {
4097 return &amp;s[1].Z.B[5][13];
4098}
4099</pre>
4100</div>
4101
4102<p>The LLVM code generated by the GCC frontend is:</p>
4103
4104<div class="doc_code">
4105<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4106%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4107%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4108
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4109define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4110entry:
4111 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4112 ret i32* %reg
4113}
4114</pre>
4115</div>
4116
4117<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4118<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]4119 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4120 }</tt>' type, a structure. The second index indexes into the third element
4121 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4122 i8 }</tt>' type, another structure. The third index indexes into the second
4123 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4124 array. The two dimensions of the array are subscripted into, yielding an
4125 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4126 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4127
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4128<p>Note that it is perfectly legal to index partially through a structure,
4129 returning a pointer to an inner element. Because of this, the LLVM code for
4130 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4131
4132<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4133 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4134 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4135 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4136 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4137 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4138 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4139 ret i32* %t5
4140 }
4141</pre>
4142
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4143<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4144 <tt>getelementptr</tt> is undefined if the base pointer is not an
4145 <i>in bounds</i> address of an allocated object, or if any of the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4146 that would be formed by successive addition of the offsets implied by the
4147 indices to the base address with infinitely precise arithmetic are not an
4148 <i>in bounds</i> address of that allocated object.
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4149 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4150 that point into the object, plus the address one byte past the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4151
4152<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4153 the base address with silently-wrapping two's complement arithmetic, and
4154 the result value of the <tt>getelementptr</tt> may be outside the object
4155 pointed to by the base pointer. The result value may not necessarily be
4156 used to access memory though, even if it happens to point into allocated
4157 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4158 section for more information.</p>
4159
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4160<p>The getelementptr instruction is often confusing. For some more insight into
4161 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4162
4163<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4164<pre>
4165 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4166 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4167 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4168 %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]4169 <i>; yields i8*:eptr</i>
4170 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4171 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4172 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4173</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4174
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4175</div>
4176
4177<!-- ======================================================================= -->
4178<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4179</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4180
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4181<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4182
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4183<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4184 which all take a single operand and a type. They perform various bit
4185 conversions on the operand.</p>
4186
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4187</div>
4188
4189<!-- _______________________________________________________________________ -->
4190<div class="doc_subsubsection">
4191 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4192</div>
4193<div class="doc_text">
4194
4195<h5>Syntax:</h5>
4196<pre>
4197 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4198</pre>
4199
4200<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4201<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4202 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4203
4204<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4205<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4206 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4207 size and type of the result, which must be
4208 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4209 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4210 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4211
4212<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4213<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4214 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4215 source size must be larger than the destination size, <tt>trunc</tt> cannot
4216 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4217
4218<h5>Example:</h5>
4219<pre>
4220 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4221 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4222 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
4223</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4224
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4225</div>
4226
4227<!-- _______________________________________________________________________ -->
4228<div class="doc_subsubsection">
4229 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4230</div>
4231<div class="doc_text">
4232
4233<h5>Syntax:</h5>
4234<pre>
4235 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4236</pre>
4237
4238<h5>Overview:</h5>
4239<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4240 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4241
4242
4243<h5>Arguments:</h5>
4244<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]4245 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4246 also be of <a href="#t_integer">integer</a> type. The bit size of the
4247 <tt>value</tt> must be smaller than the bit size of the destination type,
4248 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4249
4250<h5>Semantics:</h5>
4251<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]4252 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4253
4254<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4255
4256<h5>Example:</h5>
4257<pre>
4258 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4259 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4260</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4261
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4262</div>
4263
4264<!-- _______________________________________________________________________ -->
4265<div class="doc_subsubsection">
4266 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4267</div>
4268<div class="doc_text">
4269
4270<h5>Syntax:</h5>
4271<pre>
4272 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4273</pre>
4274
4275<h5>Overview:</h5>
4276<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4277
4278<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4279<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4280 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4281 also be of <a href="#t_integer">integer</a> type. The bit size of the
4282 <tt>value</tt> must be smaller than the bit size of the destination type,
4283 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4284
4285<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4286<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4287 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4288 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4289
4290<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4291
4292<h5>Example:</h5>
4293<pre>
4294 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4295 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4296</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4298</div>
4299
4300<!-- _______________________________________________________________________ -->
4301<div class="doc_subsubsection">
4302 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4303</div>
4304
4305<div class="doc_text">
4306
4307<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4308<pre>
4309 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4310</pre>
4311
4312<h5>Overview:</h5>
4313<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4314 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4315
4316<h5>Arguments:</h5>
4317<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4318 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4319 to cast it to. The size of <tt>value</tt> must be larger than the size of
4320 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4321 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4322
4323<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4324<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4325 <a href="#t_floating">floating point</a> type to a smaller
4326 <a href="#t_floating">floating point</a> type. If the value cannot fit
4327 within the destination type, <tt>ty2</tt>, then the results are
4328 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4329
4330<h5>Example:</h5>
4331<pre>
4332 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4333 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4334</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4335
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4336</div>
4337
4338<!-- _______________________________________________________________________ -->
4339<div class="doc_subsubsection">
4340 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4341</div>
4342<div class="doc_text">
4343
4344<h5>Syntax:</h5>
4345<pre>
4346 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4347</pre>
4348
4349<h5>Overview:</h5>
4350<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]4351 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4352
4353<h5>Arguments:</h5>
4354<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4355 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4356 a <a href="#t_floating">floating point</a> type to cast it to. The source
4357 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4358
4359<h5>Semantics:</h5>
4360<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4361 <a href="#t_floating">floating point</a> type to a larger
4362 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4363 used to make a <i>no-op cast</i> because it always changes bits. Use
4364 <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]4365
4366<h5>Example:</h5>
4367<pre>
4368 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4369 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4370</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4371
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4372</div>
4373
4374<!-- _______________________________________________________________________ -->
4375<div class="doc_subsubsection">
4376 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4377</div>
4378<div class="doc_text">
4379
4380<h5>Syntax:</h5>
4381<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4382 &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]4383</pre>
4384
4385<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4386<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4387 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4388
4389<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4390<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4391 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4392 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4393 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4394 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4395
4396<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4397<p>The '<tt>fptoui</tt>' instruction converts its
4398 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4399 towards zero) unsigned integer value. If the value cannot fit
4400 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4401
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4402<h5>Example:</h5>
4403<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4404 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4405 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4406 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4407</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4408
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4409</div>
4410
4411<!-- _______________________________________________________________________ -->
4412<div class="doc_subsubsection">
4413 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4414</div>
4415<div class="doc_text">
4416
4417<h5>Syntax:</h5>
4418<pre>
4419 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4420</pre>
4421
4422<h5>Overview:</h5>
4423<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4424 <a href="#t_floating">floating point</a> <tt>value</tt> to
4425 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4426
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4427<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4428<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4429 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4430 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4431 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4432 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4433
4434<h5>Semantics:</h5>
4435<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4436 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4437 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4438 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4439
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4440<h5>Example:</h5>
4441<pre>
4442 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4443 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4444 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4445</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4446
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4447</div>
4448
4449<!-- _______________________________________________________________________ -->
4450<div class="doc_subsubsection">
4451 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4452</div>
4453<div class="doc_text">
4454
4455<h5>Syntax:</h5>
4456<pre>
4457 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4458</pre>
4459
4460<h5>Overview:</h5>
4461<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4462 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4463
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4464<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4465<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]4466 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4467 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4468 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4469 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4470
4471<h5>Semantics:</h5>
4472<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4473 integer quantity and converts it to the corresponding floating point
4474 value. If the value cannot fit in the floating point value, the results are
4475 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4476
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4477<h5>Example:</h5>
4478<pre>
4479 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4480 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4481</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4482
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4483</div>
4484
4485<!-- _______________________________________________________________________ -->
4486<div class="doc_subsubsection">
4487 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4488</div>
4489<div class="doc_text">
4490
4491<h5>Syntax:</h5>
4492<pre>
4493 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4494</pre>
4495
4496<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4497<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4498 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4499
4500<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4501<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]4502 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4503 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4504 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4505 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4506
4507<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4508<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4509 quantity and converts it to the corresponding floating point value. If the
4510 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4511
4512<h5>Example:</h5>
4513<pre>
4514 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4515 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4516</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4517
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4518</div>
4519
4520<!-- _______________________________________________________________________ -->
4521<div class="doc_subsubsection">
4522 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4523</div>
4524<div class="doc_text">
4525
4526<h5>Syntax:</h5>
4527<pre>
4528 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4529</pre>
4530
4531<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4532<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4533 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4534
4535<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4536<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4537 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4538 <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]4539
4540<h5>Semantics:</h5>
4541<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4542 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4543 truncating or zero extending that value to the size of the integer type. If
4544 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4545 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4546 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4547 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4548
4549<h5>Example:</h5>
4550<pre>
4551 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4552 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4553</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4554
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4555</div>
4556
4557<!-- _______________________________________________________________________ -->
4558<div class="doc_subsubsection">
4559 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4560</div>
4561<div class="doc_text">
4562
4563<h5>Syntax:</h5>
4564<pre>
4565 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4566</pre>
4567
4568<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4569<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4570 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4571
4572<h5>Arguments:</h5>
4573<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4574 value to cast, and a type to cast it to, which must be a
4575 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4576
4577<h5>Semantics:</h5>
4578<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4579 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4580 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4581 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4582 than the size of a pointer then a zero extension is done. If they are the
4583 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4584
4585<h5>Example:</h5>
4586<pre>
4587 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4588 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4589 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4590</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4591
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4592</div>
4593
4594<!-- _______________________________________________________________________ -->
4595<div class="doc_subsubsection">
4596 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4597</div>
4598<div class="doc_text">
4599
4600<h5>Syntax:</h5>
4601<pre>
4602 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4603</pre>
4604
4605<h5>Overview:</h5>
4606<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4607 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4608
4609<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4610<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4611 non-aggregate first class value, and a type to cast it to, which must also be
4612 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4613 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4614 identical. If the source type is a pointer, the destination type must also be
4615 a pointer. This instruction supports bitwise conversion of vectors to
4616 integers and to vectors of other types (as long as they have the same
4617 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4618
4619<h5>Semantics:</h5>
4620<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4621 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4622 this conversion. The conversion is done as if the <tt>value</tt> had been
4623 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4624 be converted to other pointer types with this instruction. To convert
4625 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4626 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4627
4628<h5>Example:</h5>
4629<pre>
4630 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4631 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4632 %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]4633</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4634
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4635</div>
4636
4637<!-- ======================================================================= -->
4638<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4640<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4641
4642<p>The instructions in this category are the "miscellaneous" instructions, which
4643 defy better classification.</p>
4644
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4645</div>
4646
4647<!-- _______________________________________________________________________ -->
4648<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4649</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4650
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4651<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4652
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4653<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4654<pre>
4655 &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]4656</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4657
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4658<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4659<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4660 boolean values based on comparison of its two integer, integer vector, or
4661 pointer operands.</p>
4662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4663<h5>Arguments:</h5>
4664<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4665 the condition code indicating the kind of comparison to perform. It is not a
4666 value, just a keyword. The possible condition code are:</p>
4667
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4668<ol>
4669 <li><tt>eq</tt>: equal</li>
4670 <li><tt>ne</tt>: not equal </li>
4671 <li><tt>ugt</tt>: unsigned greater than</li>
4672 <li><tt>uge</tt>: unsigned greater or equal</li>
4673 <li><tt>ult</tt>: unsigned less than</li>
4674 <li><tt>ule</tt>: unsigned less or equal</li>
4675 <li><tt>sgt</tt>: signed greater than</li>
4676 <li><tt>sge</tt>: signed greater or equal</li>
4677 <li><tt>slt</tt>: signed less than</li>
4678 <li><tt>sle</tt>: signed less or equal</li>
4679</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4680
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4681<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4682 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4683 typed. They must also be identical types.</p>
4684
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4685<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4686<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4687 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4688 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]4689 result, as follows:</p>
4690
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4691<ol>
4692 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4693 <tt>false</tt> otherwise. No sign interpretation is necessary or
4694 performed.</li>
4695
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4696 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4697 <tt>false</tt> otherwise. No sign interpretation is necessary or
4698 performed.</li>
4699
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4700 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4701 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4702
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4703 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4704 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4705 to <tt>op2</tt>.</li>
4706
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4707 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4708 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4709
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4710 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4711 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4712
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4713 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4714 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4715
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4716 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4717 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4718 to <tt>op2</tt>.</li>
4719
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4720 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4721 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4722
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4723 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4724 <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]4725</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4726
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4727<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4728 values are compared as if they were integers.</p>
4729
4730<p>If the operands are integer vectors, then they are compared element by
4731 element. The result is an <tt>i1</tt> vector with the same number of elements
4732 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4733
4734<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4735<pre>
4736 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4737 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4738 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4739 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4740 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4741 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4742</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4743
4744<p>Note that the code generator does not yet support vector types with
4745 the <tt>icmp</tt> instruction.</p>
4746
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4747</div>
4748
4749<!-- _______________________________________________________________________ -->
4750<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4751</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4752
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4753<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4754
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4755<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4756<pre>
4757 &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]4758</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4759
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4760<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4761<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4762 values based on comparison of its operands.</p>
4763
4764<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]4765(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4766
4767<p>If the operands are floating point vectors, then the result type is a vector
4768 of boolean with the same number of elements as the operands being
4769 compared.</p>
4770
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4771<h5>Arguments:</h5>
4772<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4773 the condition code indicating the kind of comparison to perform. It is not a
4774 value, just a keyword. The possible condition code are:</p>
4775
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4776<ol>
4777 <li><tt>false</tt>: no comparison, always returns false</li>
4778 <li><tt>oeq</tt>: ordered and equal</li>
4779 <li><tt>ogt</tt>: ordered and greater than </li>
4780 <li><tt>oge</tt>: ordered and greater than or equal</li>
4781 <li><tt>olt</tt>: ordered and less than </li>
4782 <li><tt>ole</tt>: ordered and less than or equal</li>
4783 <li><tt>one</tt>: ordered and not equal</li>
4784 <li><tt>ord</tt>: ordered (no nans)</li>
4785 <li><tt>ueq</tt>: unordered or equal</li>
4786 <li><tt>ugt</tt>: unordered or greater than </li>
4787 <li><tt>uge</tt>: unordered or greater than or equal</li>
4788 <li><tt>ult</tt>: unordered or less than </li>
4789 <li><tt>ule</tt>: unordered or less than or equal</li>
4790 <li><tt>une</tt>: unordered or not equal</li>
4791 <li><tt>uno</tt>: unordered (either nans)</li>
4792 <li><tt>true</tt>: no comparison, always returns true</li>
4793</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4794
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4795<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4796 <i>unordered</i> means that either operand may be a QNAN.</p>
4797
4798<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4799 a <a href="#t_floating">floating point</a> type or
4800 a <a href="#t_vector">vector</a> of floating point type. They must have
4801 identical types.</p>
4802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4803<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4804<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4805 according to the condition code given as <tt>cond</tt>. If the operands are
4806 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4807 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4808 follows:</p>
4809
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4810<ol>
4811 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4812
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4813 <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]4814 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4815
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4816 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4817 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4818
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4819 <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]4820 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4821
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4822 <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]4823 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4824
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4825 <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]4826 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4827
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4828 <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]4829 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4830
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4831 <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]4832
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4833 <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]4834 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4835
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4836 <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]4837 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4838
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4839 <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]4840 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4841
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4842 <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]4843 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4844
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4845 <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]4846 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4847
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4848 <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]4849 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4850
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4851 <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]4852
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4853 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4854</ol>
4855
4856<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4857<pre>
4858 &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]4859 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4860 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4861 &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]4862</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4863
4864<p>Note that the code generator does not yet support vector types with
4865 the <tt>fcmp</tt> instruction.</p>
4866
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4867</div>
4868
4869<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4870<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4871 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4872</div>
4873
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4874<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4875
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4876<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4877<pre>
4878 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4879</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4880
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4881<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4882<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4883 SSA graph representing the function.</p>
4884
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4885<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4886<p>The type of the incoming values is specified with the first type field. After
4887 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4888 one pair for each predecessor basic block of the current block. Only values
4889 of <a href="#t_firstclass">first class</a> type may be used as the value
4890 arguments to the PHI node. Only labels may be used as the label
4891 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4892
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4893<p>There must be no non-phi instructions between the start of a basic block and
4894 the PHI instructions: i.e. PHI instructions must be first in a basic
4895 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4896
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4897<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4898 occur on the edge from the corresponding predecessor block to the current
4899 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4900 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4901
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4902<h5>Semantics:</h5>
4903<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4904 specified by the pair corresponding to the predecessor basic block that
4905 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4906
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4907<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4908<pre>
4909Loop: ; Infinite loop that counts from 0 on up...
4910 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4911 %nextindvar = add i32 %indvar, 1
4912 br label %Loop
4913</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4914
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4915</div>
4916
4917<!-- _______________________________________________________________________ -->
4918<div class="doc_subsubsection">
4919 <a name="i_select">'<tt>select</tt>' Instruction</a>
4920</div>
4921
4922<div class="doc_text">
4923
4924<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4925<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4926 &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>
4927
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4928 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4929</pre>
4930
4931<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4932<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4933 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4934
4935
4936<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4937<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4938 values indicating the condition, and two values of the
4939 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4940 vectors and the condition is a scalar, then entire vectors are selected, not
4941 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4942
4943<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4944<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4945 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4946
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4947<p>If the condition is a vector of i1, then the value arguments must be vectors
4948 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4949
4950<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4951<pre>
4952 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4953</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4954
4955<p>Note that the code generator does not yet support conditions
4956 with vector type.</p>
4957
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4958</div>
4959
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4960<!-- _______________________________________________________________________ -->
4961<div class="doc_subsubsection">
4962 <a name="i_call">'<tt>call</tt>' Instruction</a>
4963</div>
4964
4965<div class="doc_text">
4966
4967<h5>Syntax:</h5>
4968<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4969 &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]4970</pre>
4971
4972<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4973<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4974
4975<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4976<p>This instruction requires several arguments:</p>
4977
4978<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4979 <li>The optional "tail" marker indicates whether the callee function accesses
4980 any allocas or varargs in the caller. If the "tail" marker is present,
4981 the function call is eligible for tail call optimization. Note that calls
4982 may be marked "tail" even if they do not occur before
4983 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4984
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4985 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4986 convention</a> the call should use. If none is specified, the call
4987 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4988
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4989 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4990 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4991 '<tt>inreg</tt>' attributes are valid here.</li>
4992
4993 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
4994 type of the return value. Functions that return no value are marked
4995 <tt><a href="#t_void">void</a></tt>.</li>
4996
4997 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
4998 being invoked. The argument types must match the types implied by this
4999 signature. This type can be omitted if the function is not varargs and if
5000 the function type does not return a pointer to a function.</li>
5001
5002 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5003 be invoked. In most cases, this is a direct function invocation, but
5004 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5005 to function value.</li>
5006
5007 <li>'<tt>function args</tt>': argument list whose types match the function
5008 signature argument types. All arguments must be of
5009 <a href="#t_firstclass">first class</a> type. If the function signature
5010 indicates the function accepts a variable number of arguments, the extra
5011 arguments can be specified.</li>
5012
5013 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5014 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5015 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5016</ol>
5017
5018<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5019<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5020 a specified function, with its incoming arguments bound to the specified
5021 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5022 function, control flow continues with the instruction after the function
5023 call, and the return value of the function is bound to the result
5024 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5025
5026<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5027<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5028 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5029 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5030 %X = tail call i32 @foo() <i>; yields i32</i>
5031 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5032 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5033
5034 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5035 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5036 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5037 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5038 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5039 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5040</pre>
5041
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5042<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5043standard C99 library as being the C99 library functions, and may perform
5044optimizations or generate code for them under that assumption. This is
5045something we'd like to change in the future to provide better support for
5046freestanding environments and non-C-based langauges.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5047
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5048</div>
5049
5050<!-- _______________________________________________________________________ -->
5051<div class="doc_subsubsection">
5052 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5053</div>
5054
5055<div class="doc_text">
5056
5057<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5058<pre>
5059 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5060</pre>
5061
5062<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5063<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5064 the "variable argument" area of a function call. It is used to implement the
5065 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5066
5067<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5068<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5069 argument. It returns a value of the specified argument type and increments
5070 the <tt>va_list</tt> to point to the next argument. The actual type
5071 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5072
5073<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5074<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5075 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5076 to the next argument. For more information, see the variable argument
5077 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5078
5079<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]5080 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5081 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5082
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5083<p><tt>va_arg</tt> is an LLVM instruction instead of
5084 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5085 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5086
5087<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5088<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5089
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5090<p>Note that the code generator does not yet fully support va_arg on many
5091 targets. Also, it does not currently support va_arg with aggregate types on
5092 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5093
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5094</div>
5095
5096<!-- *********************************************************************** -->
5097<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5098<!-- *********************************************************************** -->
5099
5100<div class="doc_text">
5101
5102<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5103 well known names and semantics and are required to follow certain
5104 restrictions. Overall, these intrinsics represent an extension mechanism for
5105 the LLVM language that does not require changing all of the transformations
5106 in LLVM when adding to the language (or the bitcode reader/writer, the
5107 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5108
5109<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5110 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5111 begin with this prefix. Intrinsic functions must always be external
5112 functions: you cannot define the body of intrinsic functions. Intrinsic
5113 functions may only be used in call or invoke instructions: it is illegal to
5114 take the address of an intrinsic function. Additionally, because intrinsic
5115 functions are part of the LLVM language, it is required if any are added that
5116 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5117
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5118<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5119 family of functions that perform the same operation but on different data
5120 types. Because LLVM can represent over 8 million different integer types,
5121 overloading is used commonly to allow an intrinsic function to operate on any
5122 integer type. One or more of the argument types or the result type can be
5123 overloaded to accept any integer type. Argument types may also be defined as
5124 exactly matching a previous argument's type or the result type. This allows
5125 an intrinsic function which accepts multiple arguments, but needs all of them
5126 to be of the same type, to only be overloaded with respect to a single
5127 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5128
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5129<p>Overloaded intrinsics will have the names of its overloaded argument types
5130 encoded into its function name, each preceded by a period. Only those types
5131 which are overloaded result in a name suffix. Arguments whose type is matched
5132 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5133 can take an integer of any width and returns an integer of exactly the same
5134 integer width. This leads to a family of functions such as
5135 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5136 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5137 suffix is required. Because the argument's type is matched against the return
5138 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5139
5140<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5141 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5142
5143</div>
5144
5145<!-- ======================================================================= -->
5146<div class="doc_subsection">
5147 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5148</div>
5149
5150<div class="doc_text">
5151
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5152<p>Variable argument support is defined in LLVM with
5153 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5154 intrinsic functions. These functions are related to the similarly named
5155 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5156
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5157<p>All of these functions operate on arguments that use a target-specific value
5158 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5159 not define what this type is, so all transformations should be prepared to
5160 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5161
5162<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]5163 instruction and the variable argument handling intrinsic functions are
5164 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5165
5166<div class="doc_code">
5167<pre>
5168define i32 @test(i32 %X, ...) {
5169 ; Initialize variable argument processing
5170 %ap = alloca i8*
5171 %ap2 = bitcast i8** %ap to i8*
5172 call void @llvm.va_start(i8* %ap2)
5173
5174 ; Read a single integer argument
5175 %tmp = va_arg i8** %ap, i32
5176
5177 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5178 %aq = alloca i8*
5179 %aq2 = bitcast i8** %aq to i8*
5180 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5181 call void @llvm.va_end(i8* %aq2)
5182
5183 ; Stop processing of arguments.
5184 call void @llvm.va_end(i8* %ap2)
5185 ret i32 %tmp
5186}
5187
5188declare void @llvm.va_start(i8*)
5189declare void @llvm.va_copy(i8*, i8*)
5190declare void @llvm.va_end(i8*)
5191</pre>
5192</div>
5193
5194</div>
5195
5196<!-- _______________________________________________________________________ -->
5197<div class="doc_subsubsection">
5198 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5199</div>
5200
5201
5202<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5203
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5204<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5205<pre>
5206 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5207</pre>
5208
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5209<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5210<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5211 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]5212
5213<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5214<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]5215
5216<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5217<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]5218 macro available in C. In a target-dependent way, it initializes
5219 the <tt>va_list</tt> element to which the argument points, so that the next
5220 call to <tt>va_arg</tt> will produce the first variable argument passed to
5221 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5222 need to know the last argument of the function as the compiler can figure
5223 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5224
5225</div>
5226
5227<!-- _______________________________________________________________________ -->
5228<div class="doc_subsubsection">
5229 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5230</div>
5231
5232<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5233
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5234<h5>Syntax:</h5>
5235<pre>
5236 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5237</pre>
5238
5239<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5240<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5241 which has been initialized previously
5242 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5243 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5244
5245<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5246<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5247
5248<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5249<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]5250 macro available in C. In a target-dependent way, it destroys
5251 the <tt>va_list</tt> element to which the argument points. Calls
5252 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5253 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5254 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5255
5256</div>
5257
5258<!-- _______________________________________________________________________ -->
5259<div class="doc_subsubsection">
5260 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5261</div>
5262
5263<div class="doc_text">
5264
5265<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5266<pre>
5267 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5268</pre>
5269
5270<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5271<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5272 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5273
5274<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5275<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]5276 The second argument is a pointer to a <tt>va_list</tt> element to copy
5277 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5278
5279<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5280<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]5281 macro available in C. In a target-dependent way, it copies the
5282 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5283 element. This intrinsic is necessary because
5284 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5285 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5286
5287</div>
5288
5289<!-- ======================================================================= -->
5290<div class="doc_subsection">
5291 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5292</div>
5293
5294<div class="doc_text">
5295
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5296<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5297Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5298intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5299roots on the stack</a>, as well as garbage collector implementations that
5300require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5301barriers. Front-ends for type-safe garbage collected languages should generate
5302these intrinsics to make use of the LLVM garbage collectors. For more details,
5303see <a href="GarbageCollection.html">Accurate Garbage Collection with
5304LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5305
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5306<p>The garbage collection intrinsics only operate on objects in the generic
5307 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5308
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5309</div>
5310
5311<!-- _______________________________________________________________________ -->
5312<div class="doc_subsubsection">
5313 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5314</div>
5315
5316<div class="doc_text">
5317
5318<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5319<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5320 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5321</pre>
5322
5323<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5324<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]5325 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5326
5327<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5328<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5329 root pointer. The second pointer (which must be either a constant or a
5330 global value address) contains the meta-data to be associated with the
5331 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5332
5333<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5334<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]5335 location. At compile-time, the code generator generates information to allow
5336 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5337 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5338 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5339
5340</div>
5341
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5342<!-- _______________________________________________________________________ -->
5343<div class="doc_subsubsection">
5344 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5345</div>
5346
5347<div class="doc_text">
5348
5349<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5350<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5351 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5352</pre>
5353
5354<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5355<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5356 locations, allowing garbage collector implementations that require read
5357 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5358
5359<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5360<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]5361 allocated from the garbage collector. The first object is a pointer to the
5362 start of the referenced object, if needed by the language runtime (otherwise
5363 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5364
5365<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5366<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5367 instruction, but may be replaced with substantially more complex code by the
5368 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5369 may only be used in a function which <a href="#gc">specifies a GC
5370 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5371
5372</div>
5373
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5374<!-- _______________________________________________________________________ -->
5375<div class="doc_subsubsection">
5376 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5377</div>
5378
5379<div class="doc_text">
5380
5381<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5382<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5383 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5384</pre>
5385
5386<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5387<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5388 locations, allowing garbage collector implementations that require write
5389 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5390
5391<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5392<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]5393 object to store it to, and the third is the address of the field of Obj to
5394 store to. If the runtime does not require a pointer to the object, Obj may
5395 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5396
5397<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5398<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5399 instruction, but may be replaced with substantially more complex code by the
5400 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5401 may only be used in a function which <a href="#gc">specifies a GC
5402 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5403
5404</div>
5405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5406<!-- ======================================================================= -->
5407<div class="doc_subsection">
5408 <a name="int_codegen">Code Generator Intrinsics</a>
5409</div>
5410
5411<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5412
5413<p>These intrinsics are provided by LLVM to expose special features that may
5414 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5415
5416</div>
5417
5418<!-- _______________________________________________________________________ -->
5419<div class="doc_subsubsection">
5420 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5421</div>
5422
5423<div class="doc_text">
5424
5425<h5>Syntax:</h5>
5426<pre>
5427 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5428</pre>
5429
5430<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5431<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5432 target-specific value indicating the return address of the current function
5433 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5434
5435<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5436<p>The argument to this intrinsic indicates which function to return the address
5437 for. Zero indicates the calling function, one indicates its caller, etc.
5438 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5439
5440<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5441<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5442 indicating the return address of the specified call frame, or zero if it
5443 cannot be identified. The value returned by this intrinsic is likely to be
5444 incorrect or 0 for arguments other than zero, so it should only be used for
5445 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5446
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5447<p>Note that calling this intrinsic does not prevent function inlining or other
5448 aggressive transformations, so the value returned may not be that of the
5449 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5450
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5451</div>
5452
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5453<!-- _______________________________________________________________________ -->
5454<div class="doc_subsubsection">
5455 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5456</div>
5457
5458<div class="doc_text">
5459
5460<h5>Syntax:</h5>
5461<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5462 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5463</pre>
5464
5465<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5466<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5467 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5468
5469<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5470<p>The argument to this intrinsic indicates which function to return the frame
5471 pointer for. Zero indicates the calling function, one indicates its caller,
5472 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5473
5474<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5475<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5476 indicating the frame address of the specified call frame, or zero if it
5477 cannot be identified. The value returned by this intrinsic is likely to be
5478 incorrect or 0 for arguments other than zero, so it should only be used for
5479 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5480
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5481<p>Note that calling this intrinsic does not prevent function inlining or other
5482 aggressive transformations, so the value returned may not be that of the
5483 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5484
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5485</div>
5486
5487<!-- _______________________________________________________________________ -->
5488<div class="doc_subsubsection">
5489 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5490</div>
5491
5492<div class="doc_text">
5493
5494<h5>Syntax:</h5>
5495<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5496 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5497</pre>
5498
5499<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5500<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5501 of the function stack, for use
5502 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5503 useful for implementing language features like scoped automatic variable
5504 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5505
5506<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5507<p>This intrinsic returns a opaque pointer value that can be passed
5508 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5509 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5510 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5511 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5512 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5513 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5514
5515</div>
5516
5517<!-- _______________________________________________________________________ -->
5518<div class="doc_subsubsection">
5519 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5520</div>
5521
5522<div class="doc_text">
5523
5524<h5>Syntax:</h5>
5525<pre>
5526 declare void @llvm.stackrestore(i8 * %ptr)
5527</pre>
5528
5529<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5530<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5531 the function stack to the state it was in when the
5532 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5533 executed. This is useful for implementing language features like scoped
5534 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5535
5536<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5537<p>See the description
5538 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5539
5540</div>
5541
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5542<!-- _______________________________________________________________________ -->
5543<div class="doc_subsubsection">
5544 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5545</div>
5546
5547<div class="doc_text">
5548
5549<h5>Syntax:</h5>
5550<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5551 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]5552</pre>
5553
5554<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5555<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5556 insert a prefetch instruction if supported; otherwise, it is a noop.
5557 Prefetches have no effect on the behavior of the program but can change its
5558 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5559
5560<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5561<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5562 specifier determining if the fetch should be for a read (0) or write (1),
5563 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5564 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5565 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5566
5567<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5568<p>This intrinsic does not modify the behavior of the program. In particular,
5569 prefetches cannot trap and do not produce a value. On targets that support
5570 this intrinsic, the prefetch can provide hints to the processor cache for
5571 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5572
5573</div>
5574
5575<!-- _______________________________________________________________________ -->
5576<div class="doc_subsubsection">
5577 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5578</div>
5579
5580<div class="doc_text">
5581
5582<h5>Syntax:</h5>
5583<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5584 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5585</pre>
5586
5587<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5588<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5589 Counter (PC) in a region of code to simulators and other tools. The method
5590 is target specific, but it is expected that the marker will use exported
5591 symbols to transmit the PC of the marker. The marker makes no guarantees
5592 that it will remain with any specific instruction after optimizations. It is
5593 possible that the presence of a marker will inhibit optimizations. The
5594 intended use is to be inserted after optimizations to allow correlations of
5595 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5596
5597<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5598<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5599
5600<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5601<p>This intrinsic does not modify the behavior of the program. Backends that do
5602 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5603
5604</div>
5605
5606<!-- _______________________________________________________________________ -->
5607<div class="doc_subsubsection">
5608 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5609</div>
5610
5611<div class="doc_text">
5612
5613<h5>Syntax:</h5>
5614<pre>
5615 declare i64 @llvm.readcyclecounter( )
5616</pre>
5617
5618<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5619<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5620 counter register (or similar low latency, high accuracy clocks) on those
5621 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5622 should map to RPCC. As the backing counters overflow quickly (on the order
5623 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5624
5625<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5626<p>When directly supported, reading the cycle counter should not modify any
5627 memory. Implementations are allowed to either return a application specific
5628 value or a system wide value. On backends without support, this is lowered
5629 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5630
5631</div>
5632
5633<!-- ======================================================================= -->
5634<div class="doc_subsection">
5635 <a name="int_libc">Standard C Library Intrinsics</a>
5636</div>
5637
5638<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5639
5640<p>LLVM provides intrinsics for a few important standard C library functions.
5641 These intrinsics allow source-language front-ends to pass information about
5642 the alignment of the pointer arguments to the code generator, providing
5643 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5644
5645</div>
5646
5647<!-- _______________________________________________________________________ -->
5648<div class="doc_subsubsection">
5649 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5650</div>
5651
5652<div class="doc_text">
5653
5654<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5655<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5656 integer bit width. Not all targets support all bit widths however.</p>
5657
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5658<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5659 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5660 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5661 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5662 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5663 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5664 i32 &lt;len&gt;, i32 &lt;align&gt;)
5665 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5666 i64 &lt;len&gt;, i32 &lt;align&gt;)
5667</pre>
5668
5669<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5670<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5671 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5672
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5673<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5674 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5675
5676<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5677<p>The first argument is a pointer to the destination, the second is a pointer
5678 to the source. The third argument is an integer argument specifying the
5679 number of bytes to copy, and the fourth argument is the alignment of the
5680 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5681
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5682<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5683 then the caller guarantees that both the source and destination pointers are
5684 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5685
5686<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5687<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5688 source location to the destination location, which are not allowed to
5689 overlap. It copies "len" bytes of memory over. If the argument is known to
5690 be aligned to some boundary, this can be specified as the fourth argument,
5691 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5692
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5693</div>
5694
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5695<!-- _______________________________________________________________________ -->
5696<div class="doc_subsubsection">
5697 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5698</div>
5699
5700<div class="doc_text">
5701
5702<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5703<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5704 width. Not all targets support all bit widths however.</p>
5705
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5706<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5707 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5708 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5709 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5710 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5711 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5712 i32 &lt;len&gt;, i32 &lt;align&gt;)
5713 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5714 i64 &lt;len&gt;, i32 &lt;align&gt;)
5715</pre>
5716
5717<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5718<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5719 source location to the destination location. It is similar to the
5720 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5721 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5722
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5723<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5724 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5725
5726<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5727<p>The first argument is a pointer to the destination, the second is a pointer
5728 to the source. The third argument is an integer argument specifying the
5729 number of bytes to copy, and the fourth argument is the alignment of the
5730 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5731
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5732<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5733 then the caller guarantees that the source and destination pointers are
5734 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5735
5736<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5737<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5738 source location to the destination location, which may overlap. It copies
5739 "len" bytes of memory over. If the argument is known to be aligned to some
5740 boundary, this can be specified as the fourth argument, otherwise it should
5741 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5742
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5743</div>
5744
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5745<!-- _______________________________________________________________________ -->
5746<div class="doc_subsubsection">
5747 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5748</div>
5749
5750<div class="doc_text">
5751
5752<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5753<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5754 width. Not all targets support all bit widths however.</p>
5755
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5756<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5757 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5758 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5759 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5760 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5761 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5762 i32 &lt;len&gt;, i32 &lt;align&gt;)
5763 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5764 i64 &lt;len&gt;, i32 &lt;align&gt;)
5765</pre>
5766
5767<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5768<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5769 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5770
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5771<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5772 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5773
5774<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5775<p>The first argument is a pointer to the destination to fill, the second is the
5776 byte value to fill it with, the third argument is an integer argument
5777 specifying the number of bytes to fill, and the fourth argument is the known
5778 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5779
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5780<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5781 then the caller guarantees that the destination pointer is aligned to that
5782 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5783
5784<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5785<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5786 at the destination location. If the argument is known to be aligned to some
5787 boundary, this can be specified as the fourth argument, otherwise it should
5788 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5789
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5790</div>
5791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5792<!-- _______________________________________________________________________ -->
5793<div class="doc_subsubsection">
5794 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5795</div>
5796
5797<div class="doc_text">
5798
5799<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5800<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5801 floating point or vector of floating point type. Not all targets support all
5802 types however.</p>
5803
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5804<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5805 declare float @llvm.sqrt.f32(float %Val)
5806 declare double @llvm.sqrt.f64(double %Val)
5807 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5808 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5809 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5810</pre>
5811
5812<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5813<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5814 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5815 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5816 behavior for negative numbers other than -0.0 (which allows for better
5817 optimization, because there is no need to worry about errno being
5818 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]5819
5820<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5821<p>The argument and return value are floating point numbers of the same
5822 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5823
5824<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5825<p>This function returns the sqrt of the specified operand if it is a
5826 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5827
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5828</div>
5829
5830<!-- _______________________________________________________________________ -->
5831<div class="doc_subsubsection">
5832 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5833</div>
5834
5835<div class="doc_text">
5836
5837<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5838<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5839 floating point or vector of floating point type. Not all targets support all
5840 types however.</p>
5841
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5842<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5843 declare float @llvm.powi.f32(float %Val, i32 %power)
5844 declare double @llvm.powi.f64(double %Val, i32 %power)
5845 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5846 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5847 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5848</pre>
5849
5850<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5851<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5852 specified (positive or negative) power. The order of evaluation of
5853 multiplications is not defined. When a vector of floating point type is
5854 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5855
5856<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5857<p>The second argument is an integer power, and the first is a value to raise to
5858 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5859
5860<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5861<p>This function returns the first value raised to the second power with an
5862 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5863
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5864</div>
5865
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5866<!-- _______________________________________________________________________ -->
5867<div class="doc_subsubsection">
5868 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5869</div>
5870
5871<div class="doc_text">
5872
5873<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5874<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5875 floating point or vector of floating point type. Not all targets support all
5876 types however.</p>
5877
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5878<pre>
5879 declare float @llvm.sin.f32(float %Val)
5880 declare double @llvm.sin.f64(double %Val)
5881 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5882 declare fp128 @llvm.sin.f128(fp128 %Val)
5883 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5884</pre>
5885
5886<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5887<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5888
5889<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5890<p>The argument and return value are floating point numbers of the same
5891 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5892
5893<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5894<p>This function returns the sine of the specified operand, returning the same
5895 values as the libm <tt>sin</tt> functions would, and handles error conditions
5896 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5897
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5898</div>
5899
5900<!-- _______________________________________________________________________ -->
5901<div class="doc_subsubsection">
5902 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5903</div>
5904
5905<div class="doc_text">
5906
5907<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5908<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5909 floating point or vector of floating point type. Not all targets support all
5910 types however.</p>
5911
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5912<pre>
5913 declare float @llvm.cos.f32(float %Val)
5914 declare double @llvm.cos.f64(double %Val)
5915 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5916 declare fp128 @llvm.cos.f128(fp128 %Val)
5917 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5918</pre>
5919
5920<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5921<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5922
5923<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5924<p>The argument and return value are floating point numbers of the same
5925 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5926
5927<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5928<p>This function returns the cosine of the specified operand, returning the same
5929 values as the libm <tt>cos</tt> functions would, and handles error conditions
5930 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5931
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5932</div>
5933
5934<!-- _______________________________________________________________________ -->
5935<div class="doc_subsubsection">
5936 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5937</div>
5938
5939<div class="doc_text">
5940
5941<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5942<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5943 floating point or vector of floating point type. Not all targets support all
5944 types however.</p>
5945
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5946<pre>
5947 declare float @llvm.pow.f32(float %Val, float %Power)
5948 declare double @llvm.pow.f64(double %Val, double %Power)
5949 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5950 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5951 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5952</pre>
5953
5954<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5955<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5956 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5957
5958<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5959<p>The second argument is a floating point power, and the first is a value to
5960 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5961
5962<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5963<p>This function returns the first value raised to the second power, returning
5964 the same values as the libm <tt>pow</tt> functions would, and handles error
5965 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5966
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5967</div>
5968
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5969<!-- ======================================================================= -->
5970<div class="doc_subsection">
5971 <a name="int_manip">Bit Manipulation Intrinsics</a>
5972</div>
5973
5974<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5975
5976<p>LLVM provides intrinsics for a few important bit manipulation operations.
5977 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5978
5979</div>
5980
5981<!-- _______________________________________________________________________ -->
5982<div class="doc_subsubsection">
5983 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5984</div>
5985
5986<div class="doc_text">
5987
5988<h5>Syntax:</h5>
5989<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5990 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5991
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5992<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5993 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5994 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5995 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5996</pre>
5997
5998<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5999<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6000 values with an even number of bytes (positive multiple of 16 bits). These
6001 are useful for performing operations on data that is not in the target's
6002 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6003
6004<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6005<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6006 and low byte of the input i16 swapped. Similarly,
6007 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6008 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6009 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6010 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6011 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6012 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6013
6014</div>
6015
6016<!-- _______________________________________________________________________ -->
6017<div class="doc_subsubsection">
6018 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6019</div>
6020
6021<div class="doc_text">
6022
6023<h5>Syntax:</h5>
6024<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]6025 width. Not all targets support all bit widths however.</p>
6026
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6027<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6028 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6029 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6030 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6031 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6032 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6033</pre>
6034
6035<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6036<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6037 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6038
6039<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6040<p>The only argument is the value to be counted. The argument may be of any
6041 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6042
6043<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6044<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]6045
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6046</div>
6047
6048<!-- _______________________________________________________________________ -->
6049<div class="doc_subsubsection">
6050 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6051</div>
6052
6053<div class="doc_text">
6054
6055<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6056<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6057 integer bit width. Not all targets support all bit widths however.</p>
6058
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6059<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6060 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6061 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6062 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6063 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6064 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6065</pre>
6066
6067<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6068<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6069 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6070
6071<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6072<p>The only argument is the value to be counted. The argument may be of any
6073 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6074
6075<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6076<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6077 zeros in a variable. If the src == 0 then the result is the size in bits of
6078 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6079
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6080</div>
6081
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6082<!-- _______________________________________________________________________ -->
6083<div class="doc_subsubsection">
6084 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6085</div>
6086
6087<div class="doc_text">
6088
6089<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6090<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6091 integer bit width. Not all targets support all bit widths however.</p>
6092
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6093<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6094 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6095 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6096 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6097 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6098 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6099</pre>
6100
6101<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6102<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6103 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6104
6105<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6106<p>The only argument is the value to be counted. The argument may be of any
6107 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6108
6109<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6110<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6111 zeros in a variable. If the src == 0 then the result is the size in bits of
6112 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6113
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6114</div>
6115
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6116<!-- ======================================================================= -->
6117<div class="doc_subsection">
6118 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6119</div>
6120
6121<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6122
6123<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6124
6125</div>
6126
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6127<!-- _______________________________________________________________________ -->
6128<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6129 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6130</div>
6131
6132<div class="doc_text">
6133
6134<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6135<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]6136 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6137
6138<pre>
6139 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6140 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6141 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6142</pre>
6143
6144<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6145<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6146 a signed addition of the two arguments, and indicate whether an overflow
6147 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6148
6149<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6150<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]6151 be of integer types of any bit width, but they must have the same bit
6152 width. The second element of the result structure must be of
6153 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6154 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6155
6156<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6157<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6158 a signed addition of the two variables. They return a structure &mdash; the
6159 first element of which is the signed summation, and the second element of
6160 which is a bit specifying if the signed summation resulted in an
6161 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6162
6163<h5>Examples:</h5>
6164<pre>
6165 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6166 %sum = extractvalue {i32, i1} %res, 0
6167 %obit = extractvalue {i32, i1} %res, 1
6168 br i1 %obit, label %overflow, label %normal
6169</pre>
6170
6171</div>
6172
6173<!-- _______________________________________________________________________ -->
6174<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6175 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6176</div>
6177
6178<div class="doc_text">
6179
6180<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6181<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]6182 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6183
6184<pre>
6185 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6186 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6187 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6188</pre>
6189
6190<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6191<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6192 an unsigned addition of the two arguments, and indicate whether a carry
6193 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6194
6195<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6196<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]6197 be of integer types of any bit width, but they must have the same bit
6198 width. The second element of the result structure must be of
6199 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6200 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6201
6202<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6203<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6204 an unsigned addition of the two arguments. They return a structure &mdash;
6205 the first element of which is the sum, and the second element of which is a
6206 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6207
6208<h5>Examples:</h5>
6209<pre>
6210 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6211 %sum = extractvalue {i32, i1} %res, 0
6212 %obit = extractvalue {i32, i1} %res, 1
6213 br i1 %obit, label %carry, label %normal
6214</pre>
6215
6216</div>
6217
6218<!-- _______________________________________________________________________ -->
6219<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6220 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6221</div>
6222
6223<div class="doc_text">
6224
6225<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6226<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]6227 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6228
6229<pre>
6230 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6231 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6232 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6233</pre>
6234
6235<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6236<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6237 a signed subtraction of the two arguments, and indicate whether an overflow
6238 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6239
6240<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6241<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]6242 be of integer types of any bit width, but they must have the same bit
6243 width. The second element of the result structure must be of
6244 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6245 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6246
6247<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6248<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6249 a signed subtraction of the two arguments. They return a structure &mdash;
6250 the first element of which is the subtraction, and the second element of
6251 which is a bit specifying if the signed subtraction resulted in an
6252 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6253
6254<h5>Examples:</h5>
6255<pre>
6256 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6257 %sum = extractvalue {i32, i1} %res, 0
6258 %obit = extractvalue {i32, i1} %res, 1
6259 br i1 %obit, label %overflow, label %normal
6260</pre>
6261
6262</div>
6263
6264<!-- _______________________________________________________________________ -->
6265<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6266 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6267</div>
6268
6269<div class="doc_text">
6270
6271<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6272<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]6273 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6274
6275<pre>
6276 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6277 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6278 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6279</pre>
6280
6281<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6282<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6283 an unsigned subtraction of the two arguments, and indicate whether an
6284 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6285
6286<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6287<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]6288 be of integer types of any bit width, but they must have the same bit
6289 width. The second element of the result structure must be of
6290 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6291 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6292
6293<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6294<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6295 an unsigned subtraction of the two arguments. They return a structure &mdash;
6296 the first element of which is the subtraction, and the second element of
6297 which is a bit specifying if the unsigned subtraction resulted in an
6298 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6299
6300<h5>Examples:</h5>
6301<pre>
6302 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6303 %sum = extractvalue {i32, i1} %res, 0
6304 %obit = extractvalue {i32, i1} %res, 1
6305 br i1 %obit, label %overflow, label %normal
6306</pre>
6307
6308</div>
6309
6310<!-- _______________________________________________________________________ -->
6311<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6312 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6313</div>
6314
6315<div class="doc_text">
6316
6317<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6318<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]6319 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6320
6321<pre>
6322 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6323 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6324 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6325</pre>
6326
6327<h5>Overview:</h5>
6328
6329<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6330 a signed multiplication of the two arguments, and indicate whether an
6331 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6332
6333<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6334<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]6335 be of integer types of any bit width, but they must have the same bit
6336 width. The second element of the result structure must be of
6337 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6338 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6339
6340<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6341<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6342 a signed multiplication of the two arguments. They return a structure &mdash;
6343 the first element of which is the multiplication, and the second element of
6344 which is a bit specifying if the signed multiplication resulted in an
6345 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6346
6347<h5>Examples:</h5>
6348<pre>
6349 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6350 %sum = extractvalue {i32, i1} %res, 0
6351 %obit = extractvalue {i32, i1} %res, 1
6352 br i1 %obit, label %overflow, label %normal
6353</pre>
6354
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6355</div>
6356
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6357<!-- _______________________________________________________________________ -->
6358<div class="doc_subsubsection">
6359 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6360</div>
6361
6362<div class="doc_text">
6363
6364<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6365<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]6366 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6367
6368<pre>
6369 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6370 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6371 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6372</pre>
6373
6374<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6375<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6376 a unsigned multiplication of the two arguments, and indicate whether an
6377 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6378
6379<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6380<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]6381 be of integer types of any bit width, but they must have the same bit
6382 width. The second element of the result structure must be of
6383 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6384 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6385
6386<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6387<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6388 an unsigned multiplication of the two arguments. They return a structure
6389 &mdash; the first element of which is the multiplication, and the second
6390 element of which is a bit specifying if the unsigned multiplication resulted
6391 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6392
6393<h5>Examples:</h5>
6394<pre>
6395 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6396 %sum = extractvalue {i32, i1} %res, 0
6397 %obit = extractvalue {i32, i1} %res, 1
6398 br i1 %obit, label %overflow, label %normal
6399</pre>
6400
6401</div>
6402
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6403<!-- ======================================================================= -->
6404<div class="doc_subsection">
6405 <a name="int_debugger">Debugger Intrinsics</a>
6406</div>
6407
6408<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6409
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6410<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6411 prefix), are described in
6412 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6413 Level Debugging</a> document.</p>
6414
6415</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6416
6417<!-- ======================================================================= -->
6418<div class="doc_subsection">
6419 <a name="int_eh">Exception Handling Intrinsics</a>
6420</div>
6421
6422<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6423
6424<p>The LLVM exception handling intrinsics (which all start with
6425 <tt>llvm.eh.</tt> prefix), are described in
6426 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6427 Handling</a> document.</p>
6428
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6429</div>
6430
6431<!-- ======================================================================= -->
6432<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6433 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6434</div>
6435
6436<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6437
6438<p>This intrinsic makes it possible to excise one parameter, marked with
6439 the <tt>nest</tt> attribute, from a function. The result is a callable
6440 function pointer lacking the nest parameter - the caller does not need to
6441 provide a value for it. Instead, the value to use is stored in advance in a
6442 "trampoline", a block of memory usually allocated on the stack, which also
6443 contains code to splice the nest value into the argument list. This is used
6444 to implement the GCC nested function address extension.</p>
6445
6446<p>For example, if the function is
6447 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6448 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6449 follows:</p>
6450
6451<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6452<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6453 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6454 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6455 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6456 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6457</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6458</div>
6459
6460<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6461 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6462
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6463</div>
6464
6465<!-- _______________________________________________________________________ -->
6466<div class="doc_subsubsection">
6467 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6468</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6469
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6470<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6471
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6472<h5>Syntax:</h5>
6473<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6474 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]6475</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6476
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6477<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6478<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6479 function pointer suitable for executing it.</p>
6480
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6481<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6482<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6483 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6484 sufficiently aligned block of memory; this memory is written to by the
6485 intrinsic. Note that the size and the alignment are target-specific - LLVM
6486 currently provides no portable way of determining them, so a front-end that
6487 generates this intrinsic needs to have some target-specific knowledge.
6488 The <tt>func</tt> argument must hold a function bitcast to
6489 an <tt>i8*</tt>.</p>
6490
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6491<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6492<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6493 dependent code, turning it into a function. A pointer to this function is
6494 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6495 function pointer type</a> before being called. The new function's signature
6496 is the same as that of <tt>func</tt> with any arguments marked with
6497 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6498 is allowed, and it must be of pointer type. Calling the new function is
6499 equivalent to calling <tt>func</tt> with the same argument list, but
6500 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6501 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6502 by <tt>tramp</tt> is modified, then the effect of any later call to the
6503 returned function pointer is undefined.</p>
6504
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6505</div>
6506
6507<!-- ======================================================================= -->
6508<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6509 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6510</div>
6511
6512<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6513
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6514<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6515 hardware constructs for atomic operations and memory synchronization. This
6516 provides an interface to the hardware, not an interface to the programmer. It
6517 is aimed at a low enough level to allow any programming models or APIs
6518 (Application Programming Interfaces) which need atomic behaviors to map
6519 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6520 hardware provides a "universal IR" for source languages, it also provides a
6521 starting point for developing a "universal" atomic operation and
6522 synchronization IR.</p>
6523
6524<p>These do <em>not</em> form an API such as high-level threading libraries,
6525 software transaction memory systems, atomic primitives, and intrinsic
6526 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6527 application libraries. The hardware interface provided by LLVM should allow
6528 a clean implementation of all of these APIs and parallel programming models.
6529 No one model or paradigm should be selected above others unless the hardware
6530 itself ubiquitously does so.</p>
6531
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6532</div>
6533
6534<!-- _______________________________________________________________________ -->
6535<div class="doc_subsubsection">
6536 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6537</div>
6538<div class="doc_text">
6539<h5>Syntax:</h5>
6540<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6541 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]6542</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6543
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6544<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6545<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6546 specific pairs of memory access types.</p>
6547
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6548<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6549<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6550 The first four arguments enables a specific barrier as listed below. The
6551 fith argument specifies that the barrier applies to io or device or uncached
6552 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6553
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6554<ul>
6555 <li><tt>ll</tt>: load-load barrier</li>
6556 <li><tt>ls</tt>: load-store barrier</li>
6557 <li><tt>sl</tt>: store-load barrier</li>
6558 <li><tt>ss</tt>: store-store barrier</li>
6559 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6560</ul>
6561
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6562<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6563<p>This intrinsic causes the system to enforce some ordering constraints upon
6564 the loads and stores of the program. This barrier does not
6565 indicate <em>when</em> any events will occur, it only enforces
6566 an <em>order</em> in which they occur. For any of the specified pairs of load
6567 and store operations (f.ex. load-load, or store-load), all of the first
6568 operations preceding the barrier will complete before any of the second
6569 operations succeeding the barrier begin. Specifically the semantics for each
6570 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6571
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6572<ul>
6573 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6574 after the barrier begins.</li>
6575 <li><tt>ls</tt>: All loads before the barrier must complete before any
6576 store after the barrier begins.</li>
6577 <li><tt>ss</tt>: All stores before the barrier must complete before any
6578 store after the barrier begins.</li>
6579 <li><tt>sl</tt>: All stores before the barrier must complete before any
6580 load after the barrier begins.</li>
6581</ul>
6582
6583<p>These semantics are applied with a logical "and" behavior when more than one
6584 is enabled in a single memory barrier intrinsic.</p>
6585
6586<p>Backends may implement stronger barriers than those requested when they do
6587 not support as fine grained a barrier as requested. Some architectures do
6588 not need all types of barriers and on such architectures, these become
6589 noops.</p>
6590
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6591<h5>Example:</h5>
6592<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6593%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6594%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6595 store i32 4, %ptr
6596
6597%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6598 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6599 <i>; guarantee the above finishes</i>
6600 store i32 8, %ptr <i>; before this begins</i>
6601</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6602
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6603</div>
6604
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6605<!-- _______________________________________________________________________ -->
6606<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6607 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6608</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6609
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6610<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6611
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6612<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6613<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6614 any integer bit width and for different address spaces. Not all targets
6615 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6616
6617<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6618 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6619 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6620 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6621 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]6622</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6623
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6624<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6625<p>This loads a value in memory and compares it to a given value. If they are
6626 equal, it stores a new value into the memory.</p>
6627
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6628<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6629<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6630 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6631 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6632 this integer type. While any bit width integer may be used, targets may only
6633 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6634
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6635<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6636<p>This entire intrinsic must be executed atomically. It first loads the value
6637 in memory pointed to by <tt>ptr</tt> and compares it with the
6638 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6639 memory. The loaded value is yielded in all cases. This provides the
6640 equivalent of an atomic compare-and-swap operation within the SSA
6641 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6642
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6643<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6644<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6645%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6646%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6647 store i32 4, %ptr
6648
6649%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6650%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6651 <i>; yields {i32}:result1 = 4</i>
6652%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6653%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6654
6655%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6656%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6657 <i>; yields {i32}:result2 = 8</i>
6658%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6659
6660%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6661</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6662
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6663</div>
6664
6665<!-- _______________________________________________________________________ -->
6666<div class="doc_subsubsection">
6667 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6668</div>
6669<div class="doc_text">
6670<h5>Syntax:</h5>
6671
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6672<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6673 integer bit width. Not all targets support all bit widths however.</p>
6674
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6675<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6676 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6677 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6678 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6679 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]6680</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6681
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6682<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6683<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6684 the value from memory. It then stores the value in <tt>val</tt> in the memory
6685 at <tt>ptr</tt>.</p>
6686
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6687<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6688<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6689 the <tt>val</tt> argument and the result must be integers of the same bit
6690 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6691 integer type. The targets may only lower integer representations they
6692 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6693
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6694<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6695<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6696 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6697 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6698
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6699<h5>Examples:</h5>
6700<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6701%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6702%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6703 store i32 4, %ptr
6704
6705%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6706%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6707 <i>; yields {i32}:result1 = 4</i>
6708%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6709%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6710
6711%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6712%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6713 <i>; yields {i32}:result2 = 8</i>
6714
6715%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6716%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6717</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6718
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6719</div>
6720
6721<!-- _______________________________________________________________________ -->
6722<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6723 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6724
6725</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6726
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6727<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6728
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6729<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6730<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6731 any integer bit width. Not all targets support all bit widths however.</p>
6732
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6733<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6734 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6735 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6736 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6737 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]6738</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6739
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6740<h5>Overview:</h5>
6741<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6742 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6743
6744<h5>Arguments:</h5>
6745<p>The intrinsic takes two arguments, the first a pointer to an integer value
6746 and the second an integer value. The result is also an integer value. These
6747 integer types can have any bit width, but they must all have the same bit
6748 width. The targets may only lower integer representations they support.</p>
6749
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6750<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6751<p>This intrinsic does a series of operations atomically. It first loads the
6752 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6753 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]6754
6755<h5>Examples:</h5>
6756<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6757%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6758%ptr = bitcast i8* %mallocP to i32*
6759 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6760%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6761 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6762%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6763 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6764%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6765 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6766%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6767</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6768
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6769</div>
6770
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6771<!-- _______________________________________________________________________ -->
6772<div class="doc_subsubsection">
6773 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6774
6775</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6776
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6777<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6778
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6779<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6780<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6781 any integer bit width and for different address spaces. Not all targets
6782 support all bit widths however.</p>
6783
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6784<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6785 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6786 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6787 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6788 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]6789</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6790
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6791<h5>Overview:</h5>
6792<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6793 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6794
6795<h5>Arguments:</h5>
6796<p>The intrinsic takes two arguments, the first a pointer to an integer value
6797 and the second an integer value. The result is also an integer value. These
6798 integer types can have any bit width, but they must all have the same bit
6799 width. The targets may only lower integer representations they support.</p>
6800
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6801<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6802<p>This intrinsic does a series of operations atomically. It first loads the
6803 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6804 result to <tt>ptr</tt>. It yields the original value stored
6805 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6806
6807<h5>Examples:</h5>
6808<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6809%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6810%ptr = bitcast i8* %mallocP to i32*
6811 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6812%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6813 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6814%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6815 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6816%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6817 <i>; yields {i32}:result3 = 2</i>
6818%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6819</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6820
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6821</div>
6822
6823<!-- _______________________________________________________________________ -->
6824<div class="doc_subsubsection">
6825 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6826 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6827 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6828 <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]6829</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6830
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6831<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6832
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6833<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6834<p>These are overloaded intrinsics. You can
6835 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6836 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6837 bit width and for different address spaces. Not all targets support all bit
6838 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6839
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6840<pre>
6841 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6842 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6843 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6844 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]6845</pre>
6846
6847<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6848 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6849 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6850 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6851 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]6852</pre>
6853
6854<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6855 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6856 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6857 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6858 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]6859</pre>
6860
6861<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6862 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6863 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6864 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6865 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]6866</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6867
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6868<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6869<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6870 the value stored in memory at <tt>ptr</tt>. It yields the original value
6871 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6872
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6873<h5>Arguments:</h5>
6874<p>These intrinsics take two arguments, the first a pointer to an integer value
6875 and the second an integer value. The result is also an integer value. These
6876 integer types can have any bit width, but they must all have the same bit
6877 width. The targets may only lower integer representations they support.</p>
6878
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6879<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6880<p>These intrinsics does a series of operations atomically. They first load the
6881 value stored at <tt>ptr</tt>. They then do the bitwise
6882 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6883 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6884
6885<h5>Examples:</h5>
6886<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6887%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6888%ptr = bitcast i8* %mallocP to i32*
6889 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6890%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6891 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6892%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6893 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6894%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6895 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6896%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6897 <i>; yields {i32}:result3 = FF</i>
6898%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6899</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6900
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6901</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6902
6903<!-- _______________________________________________________________________ -->
6904<div class="doc_subsubsection">
6905 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6906 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6907 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6908 <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]6909</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6910
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6911<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6912
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6913<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6914<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6915 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6916 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6917 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6918
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6919<pre>
6920 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6921 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6922 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6923 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]6924</pre>
6925
6926<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6927 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6928 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6929 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6930 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]6931</pre>
6932
6933<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6934 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6935 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6936 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6937 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]6938</pre>
6939
6940<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6941 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6942 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6943 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6944 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]6945</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6946
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6947<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6948<p>These intrinsics takes the signed or unsigned minimum or maximum of
6949 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6950 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6951
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6952<h5>Arguments:</h5>
6953<p>These intrinsics take two arguments, the first a pointer to an integer value
6954 and the second an integer value. The result is also an integer value. These
6955 integer types can have any bit width, but they must all have the same bit
6956 width. The targets may only lower integer representations they support.</p>
6957
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6958<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6959<p>These intrinsics does a series of operations atomically. They first load the
6960 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6961 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6962 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6963
6964<h5>Examples:</h5>
6965<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6966%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6967%ptr = bitcast i8* %mallocP to i32*
6968 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6969%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6970 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6971%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6972 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6973%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6974 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6975%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6976 <i>; yields {i32}:result3 = 8</i>
6977%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6978</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6979
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6980</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6981
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]6982
6983<!-- ======================================================================= -->
6984<div class="doc_subsection">
6985 <a name="int_memorymarkers">Memory Use Markers</a>
6986</div>
6987
6988<div class="doc_text">
6989
6990<p>This class of intrinsics exists to information about the lifetime of memory
6991 objects and ranges where variables are immutable.</p>
6992
6993</div>
6994
6995<!-- _______________________________________________________________________ -->
6996<div class="doc_subsubsection">
6997 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
6998</div>
6999
7000<div class="doc_text">
7001
7002<h5>Syntax:</h5>
7003<pre>
7004 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7005</pre>
7006
7007<h5>Overview:</h5>
7008<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7009 object's lifetime.</p>
7010
7011<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7012<p>The first argument is a constant integer representing the size of the
7013 object, or -1 if it is variable sized. The second argument is a pointer to
7014 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7015
7016<h5>Semantics:</h5>
7017<p>This intrinsic indicates that before this point in the code, the value of the
7018 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]7019 never be used and has an undefined value. A load from the pointer that
7020 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7021 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7022
7023</div>
7024
7025<!-- _______________________________________________________________________ -->
7026<div class="doc_subsubsection">
7027 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7028</div>
7029
7030<div class="doc_text">
7031
7032<h5>Syntax:</h5>
7033<pre>
7034 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7035</pre>
7036
7037<h5>Overview:</h5>
7038<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7039 object's lifetime.</p>
7040
7041<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7042<p>The first argument is a constant integer representing the size of the
7043 object, or -1 if it is variable sized. The second argument is a pointer to
7044 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7045
7046<h5>Semantics:</h5>
7047<p>This intrinsic indicates that after this point in the code, the value of the
7048 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7049 never be used and has an undefined value. Any stores into the memory object
7050 following this intrinsic may be removed as dead.
7051
7052</div>
7053
7054<!-- _______________________________________________________________________ -->
7055<div class="doc_subsubsection">
7056 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7057</div>
7058
7059<div class="doc_text">
7060
7061<h5>Syntax:</h5>
7062<pre>
7063 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7064</pre>
7065
7066<h5>Overview:</h5>
7067<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7068 a memory object will not change.</p>
7069
7070<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7071<p>The first argument is a constant integer representing the size of the
7072 object, or -1 if it is variable sized. The second argument is a pointer to
7073 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7074
7075<h5>Semantics:</h5>
7076<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7077 the return value, the referenced memory location is constant and
7078 unchanging.</p>
7079
7080</div>
7081
7082<!-- _______________________________________________________________________ -->
7083<div class="doc_subsubsection">
7084 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7085</div>
7086
7087<div class="doc_text">
7088
7089<h5>Syntax:</h5>
7090<pre>
7091 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7092</pre>
7093
7094<h5>Overview:</h5>
7095<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7096 a memory object are mutable.</p>
7097
7098<h5>Arguments:</h5>
7099<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7100 The second argument is a constant integer representing the size of the
7101 object, or -1 if it is variable sized and the third argument is a pointer
7102 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7103
7104<h5>Semantics:</h5>
7105<p>This intrinsic indicates that the memory is mutable again.</p>
7106
7107</div>
7108
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7109<!-- ======================================================================= -->
7110<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7111 <a name="int_general">General Intrinsics</a>
7112</div>
7113
7114<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7115
7116<p>This class of intrinsics is designed to be generic and has no specific
7117 purpose.</p>
7118
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7119</div>
7120
7121<!-- _______________________________________________________________________ -->
7122<div class="doc_subsubsection">
7123 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7124</div>
7125
7126<div class="doc_text">
7127
7128<h5>Syntax:</h5>
7129<pre>
7130 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7131</pre>
7132
7133<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7134<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7135
7136<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7137<p>The first argument is a pointer to a value, the second is a pointer to a
7138 global string, the third is a pointer to a global string which is the source
7139 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7140
7141<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7142<p>This intrinsic allows annotation of local variables with arbitrary strings.
7143 This can be useful for special purpose optimizations that want to look for
7144 these annotations. These have no other defined use, they are ignored by code
7145 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7146
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7147</div>
7148
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7149<!-- _______________________________________________________________________ -->
7150<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7151 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7152</div>
7153
7154<div class="doc_text">
7155
7156<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7157<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7158 any integer bit width.</p>
7159
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7160<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7161 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7162 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7163 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7164 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7165 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]7166</pre>
7167
7168<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7169<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7170
7171<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7172<p>The first argument is an integer value (result of some expression), the
7173 second is a pointer to a global string, the third is a pointer to a global
7174 string which is the source file name, and the last argument is the line
7175 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7176
7177<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7178<p>This intrinsic allows annotations to be put on arbitrary expressions with
7179 arbitrary strings. This can be useful for special purpose optimizations that
7180 want to look for these annotations. These have no other defined use, they
7181 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7182
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7183</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7184
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7185<!-- _______________________________________________________________________ -->
7186<div class="doc_subsubsection">
7187 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7188</div>
7189
7190<div class="doc_text">
7191
7192<h5>Syntax:</h5>
7193<pre>
7194 declare void @llvm.trap()
7195</pre>
7196
7197<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7198<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7199
7200<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7201<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7202
7203<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7204<p>This intrinsics is lowered to the target dependent trap instruction. If the
7205 target does not have a trap instruction, this intrinsic will be lowered to
7206 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7207
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7208</div>
7209
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7210<!-- _______________________________________________________________________ -->
7211<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7212 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7213</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7214
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7215<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7216
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7217<h5>Syntax:</h5>
7218<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7219 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7220</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7221
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7222<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7223<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7224 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7225 ensure that it is placed on the stack before local variables.</p>
7226
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7227<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7228<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7229 arguments. The first argument is the value loaded from the stack
7230 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7231 that has enough space to hold the value of the guard.</p>
7232
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7233<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7234<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7235 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7236 stack. This is to ensure that if a local variable on the stack is
7237 overwritten, it will destroy the value of the guard. When the function exits,
7238 the guard on the stack is checked against the original guard. If they're
7239 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7240 function.</p>
7241
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7242</div>
7243
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7244<!-- *********************************************************************** -->
7245<hr>
7246<address>
7247 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7248 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7249 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7250 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]7251
7252 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7253 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7254 Last modified: $Date$
7255</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7256
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7257</body>
7258</html>