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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / ce4265b24fa707a83b564c814a66d6f4ca7e76fe / . / docs / LangRef.html
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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>
34 <li><a href="#linkage_linkonce">'<tt>linkonce_odr</tt>' Linkage</a></li>
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>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]59 <li><a href="#t_floating">Floating Point Types</a></li>
60 <li><a href="#t_void">Void Type</a></li>
61 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]62 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]63 </ol>
64 </li>
65 <li><a href="#t_derived">Derived Types</a>
66 <ol>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]67 <li><a href="#t_integer">Integer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]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>
113 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
114 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
115 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
116 </ol>
117 </li>
118 <li><a href="#binaryops">Binary Operations</a>
119 <ol>
120 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]121 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]122 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]123 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]124 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]125 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]126 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
127 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
128 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
129 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
130 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
131 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
132 </ol>
133 </li>
134 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
135 <ol>
136 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
137 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
138 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
139 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
140 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
141 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
142 </ol>
143 </li>
144 <li><a href="#vectorops">Vector Operations</a>
145 <ol>
146 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
147 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
148 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
149 </ol>
150 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]151 <li><a href="#aggregateops">Aggregate Operations</a>
152 <ol>
153 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
154 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
155 </ol>
156 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]157 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
158 <ol>
159 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
160 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
161 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
162 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
163 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
164 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
165 </ol>
166 </li>
167 <li><a href="#convertops">Conversion Operations</a>
168 <ol>
169 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
170 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
171 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
172 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
173 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
174 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
175 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
176 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
177 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
178 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
179 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
180 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
181 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]182 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]183 <li><a href="#otherops">Other Operations</a>
184 <ol>
185 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
186 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
187 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
188 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
189 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
190 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
191 </ol>
192 </li>
193 </ol>
194 </li>
195 <li><a href="#intrinsics">Intrinsic Functions</a>
196 <ol>
197 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
198 <ol>
199 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
200 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
201 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
202 </ol>
203 </li>
204 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
205 <ol>
206 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
207 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
208 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
209 </ol>
210 </li>
211 <li><a href="#int_codegen">Code Generator Intrinsics</a>
212 <ol>
213 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
214 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
215 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
216 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
217 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
218 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
219 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
220 </ol>
221 </li>
222 <li><a href="#int_libc">Standard C Library Intrinsics</a>
223 <ol>
224 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
225 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
226 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
227 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
228 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]229 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
230 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
231 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]232 </ol>
233 </li>
234 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
235 <ol>
236 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
237 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
238 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
239 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]240 </ol>
241 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]242 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
243 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]244 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
245 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
246 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
247 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
248 <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]249 <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]250 </ol>
251 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]252 <li><a href="#int_debugger">Debugger intrinsics</a></li>
253 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]254 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]255 <ol>
256 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]257 </ol>
258 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]259 <li><a href="#int_atomics">Atomic intrinsics</a>
260 <ol>
261 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
262 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
263 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
264 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
265 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
266 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
267 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
268 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
269 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
270 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
271 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
272 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
273 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
274 </ol>
275 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]276 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]277 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]278 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]279 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]280 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]281 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]282 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]283 '<tt>llvm.trap</tt>' Intrinsic</a></li>
284 <li><a href="#int_stackprotector">
285 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]286 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]287 </li>
288 </ol>
289 </li>
290</ol>
291
292<div class="doc_author">
293 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
294 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
295</div>
296
297<!-- *********************************************************************** -->
298<div class="doc_section"> <a name="abstract">Abstract </a></div>
299<!-- *********************************************************************** -->
300
301<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]302
303<p>This document is a reference manual for the LLVM assembly language. LLVM is
304 a Static Single Assignment (SSA) based representation that provides type
305 safety, low-level operations, flexibility, and the capability of representing
306 'all' high-level languages cleanly. It is the common code representation
307 used throughout all phases of the LLVM compilation strategy.</p>
308
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]309</div>
310
311<!-- *********************************************************************** -->
312<div class="doc_section"> <a name="introduction">Introduction</a> </div>
313<!-- *********************************************************************** -->
314
315<div class="doc_text">
316
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]317<p>The LLVM code representation is designed to be used in three different forms:
318 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
319 for fast loading by a Just-In-Time compiler), and as a human readable
320 assembly language representation. This allows LLVM to provide a powerful
321 intermediate representation for efficient compiler transformations and
322 analysis, while providing a natural means to debug and visualize the
323 transformations. The three different forms of LLVM are all equivalent. This
324 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]325
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]326<p>The LLVM representation aims to be light-weight and low-level while being
327 expressive, typed, and extensible at the same time. It aims to be a
328 "universal IR" of sorts, by being at a low enough level that high-level ideas
329 may be cleanly mapped to it (similar to how microprocessors are "universal
330 IR's", allowing many source languages to be mapped to them). By providing
331 type information, LLVM can be used as the target of optimizations: for
332 example, through pointer analysis, it can be proven that a C automatic
333 variable is never accessed outside of the current function... allowing it to
334 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]335
336</div>
337
338<!-- _______________________________________________________________________ -->
339<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
340
341<div class="doc_text">
342
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]343<p>It is important to note that this document describes 'well formed' LLVM
344 assembly language. There is a difference between what the parser accepts and
345 what is considered 'well formed'. For example, the following instruction is
346 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]347
348<div class="doc_code">
349<pre>
350%x = <a href="#i_add">add</a> i32 1, %x
351</pre>
352</div>
353
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]354<p>...because the definition of <tt>%x</tt> does not dominate all of its
355 uses. The LLVM infrastructure provides a verification pass that may be used
356 to verify that an LLVM module is well formed. This pass is automatically run
357 by the parser after parsing input assembly and by the optimizer before it
358 outputs bitcode. The violations pointed out by the verifier pass indicate
359 bugs in transformation passes or input to the parser.</p>
360
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]361</div>
362
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]363<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]364
365<!-- *********************************************************************** -->
366<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
367<!-- *********************************************************************** -->
368
369<div class="doc_text">
370
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]371<p>LLVM identifiers come in two basic types: global and local. Global
372 identifiers (functions, global variables) begin with the <tt>'@'</tt>
373 character. Local identifiers (register names, types) begin with
374 the <tt>'%'</tt> character. Additionally, there are three different formats
375 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]376
377<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]378 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]379 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
380 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
381 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
382 other characters in their names can be surrounded with quotes. Special
383 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
384 ASCII code for the character in hexadecimal. In this way, any character
385 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]386
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]387 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]388 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]389
390 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]391 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]392</ol>
393
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]394<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]395 don't need to worry about name clashes with reserved words, and the set of
396 reserved words may be expanded in the future without penalty. Additionally,
397 unnamed identifiers allow a compiler to quickly come up with a temporary
398 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]399
400<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]401 languages. There are keywords for different opcodes
402 ('<tt><a href="#i_add">add</a></tt>',
403 '<tt><a href="#i_bitcast">bitcast</a></tt>',
404 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
405 ('<tt><a href="#t_void">void</a></tt>',
406 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
407 reserved words cannot conflict with variable names, because none of them
408 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]409
410<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]411 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]412
413<p>The easy way:</p>
414
415<div class="doc_code">
416<pre>
417%result = <a href="#i_mul">mul</a> i32 %X, 8
418</pre>
419</div>
420
421<p>After strength reduction:</p>
422
423<div class="doc_code">
424<pre>
425%result = <a href="#i_shl">shl</a> i32 %X, i8 3
426</pre>
427</div>
428
429<p>And the hard way:</p>
430
431<div class="doc_code">
432<pre>
433<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
434<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
435%result = <a href="#i_add">add</a> i32 %1, %1
436</pre>
437</div>
438
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]439<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
440 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]441
442<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]443 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]444 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]445
446 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]447 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]448
449 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]450</ol>
451
452<p>...and it also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]453 demonstrating instructions, we will follow an instruction with a comment that
454 defines the type and name of value produced. Comments are shown in italic
455 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]456
457</div>
458
459<!-- *********************************************************************** -->
460<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
461<!-- *********************************************************************** -->
462
463<!-- ======================================================================= -->
464<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
465</div>
466
467<div class="doc_text">
468
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]469<p>LLVM programs are composed of "Module"s, each of which is a translation unit
470 of the input programs. Each module consists of functions, global variables,
471 and symbol table entries. Modules may be combined together with the LLVM
472 linker, which merges function (and global variable) definitions, resolves
473 forward declarations, and merges symbol table entries. Here is an example of
474 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]475
476<div class="doc_code">
477<pre><i>; Declare the string constant as a global constant...</i>
478<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
479 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
480
481<i>; External declaration of the puts function</i>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]482<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]483
484<i>; Definition of main function</i>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]485define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]486 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]487 %cast210 = <a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]488 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]489
490 <i>; Call puts function to write out the string to stdout...</i>
491 <a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]492 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]493 <a
494 href="#i_ret">ret</a> i32 0<br>}<br>
495</pre>
496</div>
497
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]498<p>This example is made up of a <a href="#globalvars">global variable</a> named
499 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
500 a <a href="#functionstructure">function definition</a> for
501 "<tt>main</tt>".</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]502
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]503<p>In general, a module is made up of a list of global values, where both
504 functions and global variables are global values. Global values are
505 represented by a pointer to a memory location (in this case, a pointer to an
506 array of char, and a pointer to a function), and have one of the
507 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]508
509</div>
510
511<!-- ======================================================================= -->
512<div class="doc_subsection">
513 <a name="linkage">Linkage Types</a>
514</div>
515
516<div class="doc_text">
517
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]518<p>All Global Variables and Functions have one of the following types of
519 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]520
521<dl>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]522 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]523 <dd>Global values with private linkage are only directly accessible by objects
524 in the current module. In particular, linking code into a module with an
525 private global value may cause the private to be renamed as necessary to
526 avoid collisions. Because the symbol is private to the module, all
527 references can be updated. This doesn't show up in any symbol table in the
528 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]529
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]530 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt>: </dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]531 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattner06c1ecc2009-08-24 04:32:16 +0000[diff] [blame]532 removed by the linker after evaluation. Note that (unlike private
533 symbols) linker_private symbols are subject to coalescing by the linker:
534 weak symbols get merged and redefinitions are rejected. However, unlike
535 normal strong symbols, they are removed by the linker from the final
536 linked image (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]537
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]538 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]539 <dd>Similar to private, but the value shows as a local symbol
540 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
541 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]542
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]544 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]545 into the object file corresponding to the LLVM module. They exist to
546 allow inlining and other optimizations to take place given knowledge of
547 the definition of the global, which is known to be somewhere outside the
548 module. Globals with <tt>available_externally</tt> linkage are allowed to
549 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
550 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]551
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]552 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]553 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]554 the same name when linkage occurs. This is typically used to implement
555 inline functions, templates, or other code which must be generated in each
556 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
557 allowed to be discarded.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]558
559 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]560 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
561 <tt>linkonce</tt> linkage, except that unreferenced globals with
562 <tt>weak</tt> linkage may not be discarded. This is used for globals that
563 are declared "weak" in C source code.</dd>
564
565 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
566 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
567 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
568 global scope.
569 Symbols with "<tt>common</tt>" linkage are merged in the same way as
570 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]571 <tt>common</tt> symbols may not have an explicit section,
572 must have a zero initializer, and may not be marked '<a
573 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
574 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]575
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]576
577 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]578 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]579 pointer to array type. When two global variables with appending linkage
580 are linked together, the two global arrays are appended together. This is
581 the LLVM, typesafe, equivalent of having the system linker append together
582 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]583
584 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]585 <dd>The semantics of this linkage follow the ELF object file model: the symbol
586 is weak until linked, if not linked, the symbol becomes null instead of
587 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]588
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]589 <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]590 <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]591 <dd>Some languages allow differing globals to be merged, such as two functions
592 with different semantics. Other languages, such as <tt>C++</tt>, ensure
593 that only equivalent globals are ever merged (the "one definition rule" -
594 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
595 and <tt>weak_odr</tt> linkage types to indicate that the global will only
596 be merged with equivalent globals. These linkage types are otherwise the
597 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]598
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]599 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]600 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]601 visible, meaning that it participates in linkage and can be used to
602 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]603</dl>
604
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]605<p>The next two types of linkage are targeted for Microsoft Windows platform
606 only. They are designed to support importing (exporting) symbols from (to)
607 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]608
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]609<dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]610 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]611 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]612 or variable via a global pointer to a pointer that is set up by the DLL
613 exporting the symbol. On Microsoft Windows targets, the pointer name is
614 formed by combining <code>__imp_</code> and the function or variable
615 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]616
617 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]618 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]619 pointer to a pointer in a DLL, so that it can be referenced with the
620 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
621 name is formed by combining <code>__imp_</code> and the function or
622 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]623</dl>
624
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]625<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
626 another module defined a "<tt>.LC0</tt>" variable and was linked with this
627 one, one of the two would be renamed, preventing a collision. Since
628 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
629 declarations), they are accessible outside of the current module.</p>
630
631<p>It is illegal for a function <i>declaration</i> to have any linkage type
632 other than "externally visible", <tt>dllimport</tt>
633 or <tt>extern_weak</tt>.</p>
634
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]635<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]636 or <tt>weak_odr</tt> linkages.</p>
637
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]638</div>
639
640<!-- ======================================================================= -->
641<div class="doc_subsection">
642 <a name="callingconv">Calling Conventions</a>
643</div>
644
645<div class="doc_text">
646
647<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]648 and <a href="#i_invoke">invokes</a> can all have an optional calling
649 convention specified for the call. The calling convention of any pair of
650 dynamic caller/callee must match, or the behavior of the program is
651 undefined. The following calling conventions are supported by LLVM, and more
652 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]653
654<dl>
655 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]656 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]657 specified) matches the target C calling conventions. This calling
658 convention supports varargs function calls and tolerates some mismatch in
659 the declared prototype and implemented declaration of the function (as
660 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]661
662 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]663 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]664 (e.g. by passing things in registers). This calling convention allows the
665 target to use whatever tricks it wants to produce fast code for the
666 target, without having to conform to an externally specified ABI
667 (Application Binary Interface). Implementations of this convention should
668 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
669 optimization</a> to be supported. This calling convention does not
670 support varargs and requires the prototype of all callees to exactly match
671 the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]672
673 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]674 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]675 as possible under the assumption that the call is not commonly executed.
676 As such, these calls often preserve all registers so that the call does
677 not break any live ranges in the caller side. This calling convention
678 does not support varargs and requires the prototype of all callees to
679 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]680
681 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]682 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]683 target-specific calling conventions to be used. Target specific calling
684 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]685</dl>
686
687<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]688 support Pascal conventions or any other well-known target-independent
689 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]690
691</div>
692
693<!-- ======================================================================= -->
694<div class="doc_subsection">
695 <a name="visibility">Visibility Styles</a>
696</div>
697
698<div class="doc_text">
699
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]700<p>All Global Variables and Functions have one of the following visibility
701 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]702
703<dl>
704 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]705 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]706 that the declaration is visible to other modules and, in shared libraries,
707 means that the declared entity may be overridden. On Darwin, default
708 visibility means that the declaration is visible to other modules. Default
709 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]710
711 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]712 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]713 object if they are in the same shared object. Usually, hidden visibility
714 indicates that the symbol will not be placed into the dynamic symbol
715 table, so no other module (executable or shared library) can reference it
716 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]717
718 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]719 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]720 the dynamic symbol table, but that references within the defining module
721 will bind to the local symbol. That is, the symbol cannot be overridden by
722 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]723</dl>
724
725</div>
726
727<!-- ======================================================================= -->
728<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]729 <a name="namedtypes">Named Types</a>
730</div>
731
732<div class="doc_text">
733
734<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]735 it easier to read the IR and make the IR more condensed (particularly when
736 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]737
738<div class="doc_code">
739<pre>
740%mytype = type { %mytype*, i32 }
741</pre>
742</div>
743
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]744<p>You may give a name to any <a href="#typesystem">type</a> except
745 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
746 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]747
748<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]749 and that you can therefore specify multiple names for the same type. This
750 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
751 uses structural typing, the name is not part of the type. When printing out
752 LLVM IR, the printer will pick <em>one name</em> to render all types of a
753 particular shape. This means that if you have code where two different
754 source types end up having the same LLVM type, that the dumper will sometimes
755 print the "wrong" or unexpected type. This is an important design point and
756 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]757
758</div>
759
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]760<!-- ======================================================================= -->
761<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]762 <a name="globalvars">Global Variables</a>
763</div>
764
765<div class="doc_text">
766
767<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]768 instead of run-time. Global variables may optionally be initialized, may
769 have an explicit section to be placed in, and may have an optional explicit
770 alignment specified. A variable may be defined as "thread_local", which
771 means that it will not be shared by threads (each thread will have a
772 separated copy of the variable). A variable may be defined as a global
773 "constant," which indicates that the contents of the variable
774 will <b>never</b> be modified (enabling better optimization, allowing the
775 global data to be placed in the read-only section of an executable, etc).
776 Note that variables that need runtime initialization cannot be marked
777 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]778
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]779<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
780 constant, even if the final definition of the global is not. This capability
781 can be used to enable slightly better optimization of the program, but
782 requires the language definition to guarantee that optimizations based on the
783 'constantness' are valid for the translation units that do not include the
784 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]785
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]786<p>As SSA values, global variables define pointer values that are in scope
787 (i.e. they dominate) all basic blocks in the program. Global variables
788 always define a pointer to their "content" type because they describe a
789 region of memory, and all memory objects in LLVM are accessed through
790 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]791
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]792<p>A global variable may be declared to reside in a target-specific numbered
793 address space. For targets that support them, address spaces may affect how
794 optimizations are performed and/or what target instructions are used to
795 access the variable. The default address space is zero. The address space
796 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]797
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]798<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]799 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]800
801<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]802 the alignment is set to zero, the alignment of the global is set by the
803 target to whatever it feels convenient. If an explicit alignment is
804 specified, the global is forced to have at least that much alignment. All
805 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]806
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]807<p>For example, the following defines a global in a numbered address space with
808 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]809
810<div class="doc_code">
811<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]812@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]813</pre>
814</div>
815
816</div>
817
818
819<!-- ======================================================================= -->
820<div class="doc_subsection">
821 <a name="functionstructure">Functions</a>
822</div>
823
824<div class="doc_text">
825
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]826<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
827 optional <a href="#linkage">linkage type</a>, an optional
828 <a href="#visibility">visibility style</a>, an optional
829 <a href="#callingconv">calling convention</a>, a return type, an optional
830 <a href="#paramattrs">parameter attribute</a> for the return type, a function
831 name, a (possibly empty) argument list (each with optional
832 <a href="#paramattrs">parameter attributes</a>), optional
833 <a href="#fnattrs">function attributes</a>, an optional section, an optional
834 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
835 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]836
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]837<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
838 optional <a href="#linkage">linkage type</a>, an optional
839 <a href="#visibility">visibility style</a>, an optional
840 <a href="#callingconv">calling convention</a>, a return type, an optional
841 <a href="#paramattrs">parameter attribute</a> for the return type, a function
842 name, a possibly empty list of arguments, an optional alignment, and an
843 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]844
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]845<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]846 (Control Flow Graph) for the function. Each basic block may optionally start
847 with a label (giving the basic block a symbol table entry), contains a list
848 of instructions, and ends with a <a href="#terminators">terminator</a>
849 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]850
851<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]852 executed on entrance to the function, and it is not allowed to have
853 predecessor basic blocks (i.e. there can not be any branches to the entry
854 block of a function). Because the block can have no predecessors, it also
855 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]856
857<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]858 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]859
860<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]861 the alignment is set to zero, the alignment of the function is set by the
862 target to whatever it feels convenient. If an explicit alignment is
863 specified, the function is forced to have at least that much alignment. All
864 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]865
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]866<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]867<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]868<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]869define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]870 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
871 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
872 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
873 [<a href="#gc">gc</a>] { ... }
874</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]875</div>
876
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]877</div>
878
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]879<!-- ======================================================================= -->
880<div class="doc_subsection">
881 <a name="aliasstructure">Aliases</a>
882</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]883
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]884<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]885
886<p>Aliases act as "second name" for the aliasee value (which can be either
887 function, global variable, another alias or bitcast of global value). Aliases
888 may have an optional <a href="#linkage">linkage type</a>, and an
889 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]890
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]891<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]892<div class="doc_code">
893<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]894@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]895</pre>
896</div>
897
898</div>
899
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]900<!-- ======================================================================= -->
901<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]902
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]903<div class="doc_text">
904
905<p>The return type and each parameter of a function type may have a set of
906 <i>parameter attributes</i> associated with them. Parameter attributes are
907 used to communicate additional information about the result or parameters of
908 a function. Parameter attributes are considered to be part of the function,
909 not of the function type, so functions with different parameter attributes
910 can have the same function type.</p>
911
912<p>Parameter attributes are simple keywords that follow the type specified. If
913 multiple parameter attributes are needed, they are space separated. For
914 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]915
916<div class="doc_code">
917<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]918declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]919declare i32 @atoi(i8 zeroext)
920declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]921</pre>
922</div>
923
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]924<p>Note that any attributes for the function result (<tt>nounwind</tt>,
925 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]926
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]927<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]928
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]929<dl>
930 <dt><tt>zeroext</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]931 <dd>This indicates to the code generator that the parameter or return value
932 should be zero-extended to a 32-bit value by the caller (for a parameter)
933 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]934
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]935 <dt><tt>signext</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]936 <dd>This indicates to the code generator that the parameter or return value
937 should be sign-extended to a 32-bit value by the caller (for a parameter)
938 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]939
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]940 <dt><tt>inreg</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]941 <dd>This indicates that this parameter or return value should be treated in a
942 special target-dependent fashion during while emitting code for a function
943 call or return (usually, by putting it in a register as opposed to memory,
944 though some targets use it to distinguish between two different kinds of
945 registers). Use of this attribute is target-specific.</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><a name="byval">byval</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]948 <dd>This indicates that the pointer parameter should really be passed by value
949 to the function. The attribute implies that a hidden copy of the pointee
950 is made between the caller and the callee, so the callee is unable to
951 modify the value in the callee. This attribute is only valid on LLVM
952 pointer arguments. It is generally used to pass structs and arrays by
953 value, but is also valid on pointers to scalars. The copy is considered
954 to belong to the caller not the callee (for example,
955 <tt><a href="#readonly">readonly</a></tt> functions should not write to
956 <tt>byval</tt> parameters). This is not a valid attribute for return
957 values. The byval attribute also supports specifying an alignment with
958 the align attribute. This has a target-specific effect on the code
959 generator that usually indicates a desired alignment for the synthesized
960 stack slot.</dd>
961
962 <dt><tt>sret</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]963 <dd>This indicates that the pointer parameter specifies the address of a
964 structure that is the return value of the function in the source program.
965 This pointer must be guaranteed by the caller to be valid: loads and
966 stores to the structure may be assumed by the callee to not to trap. This
967 may only be applied to the first parameter. This is not a valid attribute
968 for return values. </dd>
969
970 <dt><tt>noalias</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]971 <dd>This indicates that the pointer does not alias any global or any other
972 parameter. The caller is responsible for ensuring that this is the
973 case. On a function return value, <tt>noalias</tt> additionally indicates
974 that the pointer does not alias any other pointers visible to the
975 caller. For further details, please see the discussion of the NoAlias
976 response in
977 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
978 analysis</a>.</dd>
979
980 <dt><tt>nocapture</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]981 <dd>This indicates that the callee does not make any copies of the pointer
982 that outlive the callee itself. This is not a valid attribute for return
983 values.</dd>
984
985 <dt><tt>nest</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]986 <dd>This indicates that the pointer parameter can be excised using the
987 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
988 attribute for return values.</dd>
989</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]990
991</div>
992
993<!-- ======================================================================= -->
994<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]995 <a name="gc">Garbage Collector Names</a>
996</div>
997
998<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]999
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1000<p>Each function may specify a garbage collector name, which is simply a
1001 string:</p>
1002
1003<div class="doc_code">
1004<pre>
1005define void @f() gc "name" { ...
1006</pre>
1007</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1008
1009<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1010 collector which will cause the compiler to alter its output in order to
1011 support the named garbage collection algorithm.</p>
1012
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1013</div>
1014
1015<!-- ======================================================================= -->
1016<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1017 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1018</div>
1019
1020<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1021
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1022<p>Function attributes are set to communicate additional information about a
1023 function. Function attributes are considered to be part of the function, not
1024 of the function type, so functions with different parameter attributes can
1025 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1026
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1027<p>Function attributes are simple keywords that follow the type specified. If
1028 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1029
1030<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1031<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1032define void @f() noinline { ... }
1033define void @f() alwaysinline { ... }
1034define void @f() alwaysinline optsize { ... }
1035define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1036</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1037</div>
1038
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1039<dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1040 <dt><tt>alwaysinline</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1041 <dd>This attribute indicates that the inliner should attempt to inline this
1042 function into callers whenever possible, ignoring any active inlining size
1043 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1044
Dale Johannesen7fd6b0f2009-08-26 01:08:21 +0000[diff] [blame]1045 <dt><tt>inlinehint</tt></dt>
1046 <dd>This attribute indicates that the source code contained a hint that inlining
1047 this function is desirable (such as the "inline" keyword in C/C++). It
1048 is just a hint; it imposes no requirements on the inliner.</dd>
1049
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1050 <dt><tt>noinline</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1051 <dd>This attribute indicates that the inliner should never inline this
1052 function in any situation. This attribute may not be used together with
1053 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1054
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1055 <dt><tt>optsize</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1056 <dd>This attribute suggests that optimization passes and code generator passes
1057 make choices that keep the code size of this function low, and otherwise
1058 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1059
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1060 <dt><tt>noreturn</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1061 <dd>This function attribute indicates that the function never returns
1062 normally. This produces undefined behavior at runtime if the function
1063 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1064
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1065 <dt><tt>nounwind</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1066 <dd>This function attribute indicates that the function never returns with an
1067 unwind or exceptional control flow. If the function does unwind, its
1068 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1069
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1070 <dt><tt>readnone</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1071 <dd>This attribute indicates that the function computes its result (or decides
1072 to unwind an exception) based strictly on its arguments, without
1073 dereferencing any pointer arguments or otherwise accessing any mutable
1074 state (e.g. memory, control registers, etc) visible to caller functions.
1075 It does not write through any pointer arguments
1076 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1077 changes any state visible to callers. This means that it cannot unwind
1078 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1079 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1080
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1081 <dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1082 <dd>This attribute indicates that the function does not write through any
1083 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1084 arguments) or otherwise modify any state (e.g. memory, control registers,
1085 etc) visible to caller functions. It may dereference pointer arguments
1086 and read state that may be set in the caller. A readonly function always
1087 returns the same value (or unwinds an exception identically) when called
1088 with the same set of arguments and global state. It cannot unwind an
1089 exception by calling the <tt>C++</tt> exception throwing methods, but may
1090 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1091
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1092 <dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1093 <dd>This attribute indicates that the function should emit a stack smashing
1094 protector. It is in the form of a "canary"&mdash;a random value placed on
1095 the stack before the local variables that's checked upon return from the
1096 function to see if it has been overwritten. A heuristic is used to
1097 determine if a function needs stack protectors or not.<br>
1098<br>
1099 If a function that has an <tt>ssp</tt> attribute is inlined into a
1100 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1101 function will have an <tt>ssp</tt> attribute.</dd>
1102
1103 <dt><tt>sspreq</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1104 <dd>This attribute indicates that the function should <em>always</em> emit a
1105 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1106 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1107<br>
1108 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1109 function that doesn't have an <tt>sspreq</tt> attribute or which has
1110 an <tt>ssp</tt> attribute, then the resulting function will have
1111 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1112
1113 <dt><tt>noredzone</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1114 <dd>This attribute indicates that the code generator should not use a red
1115 zone, even if the target-specific ABI normally permits it.</dd>
1116
1117 <dt><tt>noimplicitfloat</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1118 <dd>This attributes disables implicit floating point instructions.</dd>
1119
1120 <dt><tt>naked</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1121 <dd>This attribute disables prologue / epilogue emission for the function.
1122 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1123</dl>
1124
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1125</div>
1126
1127<!-- ======================================================================= -->
1128<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1129 <a name="moduleasm">Module-Level Inline Assembly</a>
1130</div>
1131
1132<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1133
1134<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1135 the GCC "file scope inline asm" blocks. These blocks are internally
1136 concatenated by LLVM and treated as a single unit, but may be separated in
1137 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1138
1139<div class="doc_code">
1140<pre>
1141module asm "inline asm code goes here"
1142module asm "more can go here"
1143</pre>
1144</div>
1145
1146<p>The strings can contain any character by escaping non-printable characters.
1147 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]1148 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1149
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1150<p>The inline asm code is simply printed to the machine code .s file when
1151 assembly code is generated.</p>
1152
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1153</div>
1154
1155<!-- ======================================================================= -->
1156<div class="doc_subsection">
1157 <a name="datalayout">Data Layout</a>
1158</div>
1159
1160<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1161
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1162<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1163 data is to be laid out in memory. The syntax for the data layout is
1164 simply:</p>
1165
1166<div class="doc_code">
1167<pre>
1168target datalayout = "<i>layout specification</i>"
1169</pre>
1170</div>
1171
1172<p>The <i>layout specification</i> consists of a list of specifications
1173 separated by the minus sign character ('-'). Each specification starts with
1174 a letter and may include other information after the letter to define some
1175 aspect of the data layout. The specifications accepted are as follows:</p>
1176
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1177<dl>
1178 <dt><tt>E</tt></dt>
1179 <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]1180 bits with the most significance have the lowest address location.</dd>
1181
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1182 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1183 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1184 the bits with the least significance have the lowest address
1185 location.</dd>
1186
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1187 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1188 <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]1189 <i>preferred</i> alignments. All sizes are in bits. Specifying
1190 the <i>pref</i> alignment is optional. If omitted, the
1191 preceding <tt>:</tt> should be omitted too.</dd>
1192
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1193 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1194 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1195 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1196
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1197 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1198 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1199 <i>size</i>.</dd>
1200
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1201 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1202 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1203 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1204 (double).</dd>
1205
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1206 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1207 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1208 <i>size</i>.</dd>
1209
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1210 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1211 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1212 <i>size</i>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1213</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1214
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1215<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1216 default set of specifications which are then (possibly) overriden by the
1217 specifications in the <tt>datalayout</tt> keyword. The default specifications
1218 are given in this list:</p>
1219
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1220<ul>
1221 <li><tt>E</tt> - big endian</li>
1222 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1223 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1224 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1225 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1226 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1227 <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]1228 alignment of 64-bits</li>
1229 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1230 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1231 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1232 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1233 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1234 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1235</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1236
1237<p>When LLVM is determining the alignment for a given type, it uses the
1238 following rules:</p>
1239
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1240<ol>
1241 <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]1242 specification is used.</li>
1243
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1244 <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]1245 smallest integer type that is larger than the bitwidth of the sought type
1246 is used. If none of the specifications are larger than the bitwidth then
1247 the the largest integer type is used. For example, given the default
1248 specifications above, the i7 type will use the alignment of i8 (next
1249 largest) while both i65 and i256 will use the alignment of i64 (largest
1250 specified).</li>
1251
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1252 <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]1253 largest vector type that is smaller than the sought vector type will be
1254 used as a fall back. This happens because &lt;128 x double&gt; can be
1255 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1256</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1257
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1258</div>
1259
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1260<!-- ======================================================================= -->
1261<div class="doc_subsection">
1262 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1263</div>
1264
1265<div class="doc_text">
1266
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1267<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1268with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1269is undefined. Pointer values are associated with address ranges
1270according to the following rules:</p>
1271
1272<ul>
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1273 <li>A pointer value formed from a
1274 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1275 is associated with the addresses associated with the first operand
1276 of the <tt>getelementptr</tt>.</li>
1277 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1278 range of the variable's storage.</li>
1279 <li>The result value of an allocation instruction is associated with
1280 the address range of the allocated storage.</li>
1281 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1282 no address.</li>
1283 <li>A pointer value formed by an
1284 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1285 address ranges of all pointer values that contribute (directly or
1286 indirectly) to the computation of the pointer's value.</li>
1287 <li>The result value of a
1288 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1289 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1290 <li>An integer constant other than zero or a pointer value returned
1291 from a function not defined within LLVM may be associated with address
1292 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1293 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1294 allocated by mechanisms provided by LLVM.</li>
1295 </ul>
1296
1297<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1298<tt><a href="#i_load">load</a></tt> merely indicates the size and
1299alignment of the memory from which to load, as well as the
1300interpretation of the value. The first operand of a
1301<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1302and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1303
1304<p>Consequently, type-based alias analysis, aka TBAA, aka
1305<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1306LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1307additional information which specialized optimization passes may use
1308to implement type-based alias analysis.</p>
1309
1310</div>
1311
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1312<!-- *********************************************************************** -->
1313<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1314<!-- *********************************************************************** -->
1315
1316<div class="doc_text">
1317
1318<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1319 intermediate representation. Being typed enables a number of optimizations
1320 to be performed on the intermediate representation directly, without having
1321 to do extra analyses on the side before the transformation. A strong type
1322 system makes it easier to read the generated code and enables novel analyses
1323 and transformations that are not feasible to perform on normal three address
1324 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1325
1326</div>
1327
1328<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1329<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1330Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1331
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1332<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1333
1334<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1335
1336<table border="1" cellspacing="0" cellpadding="4">
1337 <tbody>
1338 <tr><th>Classification</th><th>Types</th></tr>
1339 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1340 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1341 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1342 </tr>
1343 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1344 <td><a href="#t_floating">floating point</a></td>
1345 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1346 </tr>
1347 <tr>
1348 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1349 <td><a href="#t_integer">integer</a>,
1350 <a href="#t_floating">floating point</a>,
1351 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1352 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1353 <a href="#t_struct">structure</a>,
1354 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1355 <a href="#t_label">label</a>,
1356 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1357 </td>
1358 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1359 <tr>
1360 <td><a href="#t_primitive">primitive</a></td>
1361 <td><a href="#t_label">label</a>,
1362 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1363 <a href="#t_floating">floating point</a>,
1364 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1365 </tr>
1366 <tr>
1367 <td><a href="#t_derived">derived</a></td>
1368 <td><a href="#t_integer">integer</a>,
1369 <a href="#t_array">array</a>,
1370 <a href="#t_function">function</a>,
1371 <a href="#t_pointer">pointer</a>,
1372 <a href="#t_struct">structure</a>,
1373 <a href="#t_pstruct">packed structure</a>,
1374 <a href="#t_vector">vector</a>,
1375 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1376 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1377 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1378 </tbody>
1379</table>
1380
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1381<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1382 important. Values of these types are the only ones which can be produced by
1383 instructions, passed as arguments, or used as operands to instructions.</p>
1384
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1385</div>
1386
1387<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1388<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1389
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1390<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1391
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1392<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1393 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1394
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1395</div>
1396
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1397<!-- _______________________________________________________________________ -->
1398<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1399
1400<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1401
1402<table>
1403 <tbody>
1404 <tr><th>Type</th><th>Description</th></tr>
1405 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1406 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1407 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1408 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1409 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1410 </tbody>
1411</table>
1412
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1413</div>
1414
1415<!-- _______________________________________________________________________ -->
1416<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1417
1418<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1419
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1420<h5>Overview:</h5>
1421<p>The void type does not represent any value and has no size.</p>
1422
1423<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1424<pre>
1425 void
1426</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1427
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1428</div>
1429
1430<!-- _______________________________________________________________________ -->
1431<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1432
1433<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1434
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1435<h5>Overview:</h5>
1436<p>The label type represents code labels.</p>
1437
1438<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1439<pre>
1440 label
1441</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1442
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1443</div>
1444
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1445<!-- _______________________________________________________________________ -->
1446<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1447
1448<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1449
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1450<h5>Overview:</h5>
1451<p>The metadata type represents embedded metadata. The only derived type that
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1452 may contain metadata is <tt>metadata*</tt> or a function type that returns or
1453 takes metadata typed parameters, but not pointer to metadata types.</p>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1454
1455<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1456<pre>
1457 metadata
1458</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1459
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1460</div>
1461
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1462
1463<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1464<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1465
1466<div class="doc_text">
1467
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1468<p>The real power in LLVM comes from the derived types in the system. This is
1469 what allows a programmer to represent arrays, functions, pointers, and other
1470 useful types. Note that these derived types may be recursive: For example,
1471 it is possible to have a two dimensional array.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1472
1473</div>
1474
1475<!-- _______________________________________________________________________ -->
1476<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1477
1478<div class="doc_text">
1479
1480<h5>Overview:</h5>
1481<p>The integer type is a very simple derived type that simply specifies an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1482 arbitrary bit width for the integer type desired. Any bit width from 1 bit to
1483 2^23-1 (about 8 million) can be specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1484
1485<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1486<pre>
1487 iN
1488</pre>
1489
1490<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1491 value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1492
1493<h5>Examples:</h5>
1494<table class="layout">
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1495 <tr class="layout">
1496 <td class="left"><tt>i1</tt></td>
1497 <td class="left">a single-bit integer.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1498 </tr>
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1499 <tr class="layout">
1500 <td class="left"><tt>i32</tt></td>
1501 <td class="left">a 32-bit integer.</td>
1502 </tr>
1503 <tr class="layout">
1504 <td class="left"><tt>i1942652</tt></td>
1505 <td class="left">a really big integer of over 1 million bits.</td>
1506 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1507</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1508
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1509<p>Note that the code generator does not yet support large integer types to be
1510 used as function return types. The specific limit on how large a return type
1511 the code generator can currently handle is target-dependent; currently it's
1512 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1513
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1514</div>
1515
1516<!-- _______________________________________________________________________ -->
1517<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1518
1519<div class="doc_text">
1520
1521<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1522<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1523 sequentially in memory. The array type requires a size (number of elements)
1524 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1525
1526<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1527<pre>
1528 [&lt;# elements&gt; x &lt;elementtype&gt;]
1529</pre>
1530
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1531<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1532 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1533
1534<h5>Examples:</h5>
1535<table class="layout">
1536 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1537 <td class="left"><tt>[40 x i32]</tt></td>
1538 <td class="left">Array of 40 32-bit integer values.</td>
1539 </tr>
1540 <tr class="layout">
1541 <td class="left"><tt>[41 x i32]</tt></td>
1542 <td class="left">Array of 41 32-bit integer values.</td>
1543 </tr>
1544 <tr class="layout">
1545 <td class="left"><tt>[4 x i8]</tt></td>
1546 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1547 </tr>
1548</table>
1549<p>Here are some examples of multidimensional arrays:</p>
1550<table class="layout">
1551 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1552 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1553 <td class="left">3x4 array of 32-bit integer values.</td>
1554 </tr>
1555 <tr class="layout">
1556 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1557 <td class="left">12x10 array of single precision floating point values.</td>
1558 </tr>
1559 <tr class="layout">
1560 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1561 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1562 </tr>
1563</table>
1564
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1565<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1566 length array. Normally, accesses past the end of an array are undefined in
1567 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1568 a special case, however, zero length arrays are recognized to be variable
1569 length. This allows implementation of 'pascal style arrays' with the LLVM
1570 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1571
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1572<p>Note that the code generator does not yet support large aggregate types to be
1573 used as function return types. The specific limit on how large an aggregate
1574 return type the code generator can currently handle is target-dependent, and
1575 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1576
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1577</div>
1578
1579<!-- _______________________________________________________________________ -->
1580<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1581
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1582<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1583
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1584<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1585<p>The function type can be thought of as a function signature. It consists of
1586 a return type and a list of formal parameter types. The return type of a
1587 function type is a scalar type, a void type, or a struct type. If the return
1588 type is a struct type then all struct elements must be of first class types,
1589 and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1590
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1591<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1592<pre>
1593 &lt;returntype list&gt; (&lt;parameter list&gt;)
1594</pre>
1595
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1596<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]1597 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1598 which indicates that the function takes a variable number of arguments.
1599 Variable argument functions can access their arguments with
1600 the <a href="#int_varargs">variable argument handling intrinsic</a>
1601 functions. '<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1602 <a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1604<h5>Examples:</h5>
1605<table class="layout">
1606 <tr class="layout">
1607 <td class="left"><tt>i32 (i32)</tt></td>
1608 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1609 </td>
1610 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1611 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1612 </tt></td>
1613 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1614 an <tt>i16</tt> that should be sign extended and a
1615 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1616 <tt>float</tt>.
1617 </td>
1618 </tr><tr class="layout">
1619 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1620 <td class="left">A vararg function that takes at least one
1621 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1622 which returns an integer. This is the signature for <tt>printf</tt> in
1623 LLVM.
1624 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1625 </tr><tr class="layout">
1626 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1627 <td class="left">A function taking an <tt>i32</tt>, returning two
1628 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1629 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1630 </tr>
1631</table>
1632
1633</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1634
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1635<!-- _______________________________________________________________________ -->
1636<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1637
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1638<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1640<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1641<p>The structure type is used to represent a collection of data members together
1642 in memory. The packing of the field types is defined to match the ABI of the
1643 underlying processor. The elements of a structure may be any type that has a
1644 size.</p>
1645
1646<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1647 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1648 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1650<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1651<pre>
1652 { &lt;type list&gt; }
1653</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1654
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1655<h5>Examples:</h5>
1656<table class="layout">
1657 <tr class="layout">
1658 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1659 <td class="left">A triple of three <tt>i32</tt> values</td>
1660 </tr><tr class="layout">
1661 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1662 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1663 second element is a <a href="#t_pointer">pointer</a> to a
1664 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1665 an <tt>i32</tt>.</td>
1666 </tr>
1667</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1668
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1669<p>Note that the code generator does not yet support large aggregate types to be
1670 used as function return types. The specific limit on how large an aggregate
1671 return type the code generator can currently handle is target-dependent, and
1672 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1673
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1674</div>
1675
1676<!-- _______________________________________________________________________ -->
1677<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1678</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1679
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1680<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1681
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1682<h5>Overview:</h5>
1683<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1684 together in memory. There is no padding between fields. Further, the
1685 alignment of a packed structure is 1 byte. The elements of a packed
1686 structure may be any type that has a size.</p>
1687
1688<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1689 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1690 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1691
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1692<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1693<pre>
1694 &lt; { &lt;type list&gt; } &gt;
1695</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1696
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1697<h5>Examples:</h5>
1698<table class="layout">
1699 <tr class="layout">
1700 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1701 <td class="left">A triple of three <tt>i32</tt> values</td>
1702 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1703 <td class="left">
1704<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1705 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1706 second element is a <a href="#t_pointer">pointer</a> to a
1707 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1708 an <tt>i32</tt>.</td>
1709 </tr>
1710</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1711
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1712</div>
1713
1714<!-- _______________________________________________________________________ -->
1715<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1716
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1717<div class="doc_text">
1718
1719<h5>Overview:</h5>
1720<p>As in many languages, the pointer type represents a pointer or reference to
1721 another object, which must live in memory. Pointer types may have an optional
1722 address space attribute defining the target-specific numbered address space
1723 where the pointed-to object resides. The default address space is zero.</p>
1724
1725<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1726 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1727
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1728<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1729<pre>
1730 &lt;type&gt; *
1731</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1732
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1733<h5>Examples:</h5>
1734<table class="layout">
1735 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1736 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1737 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1738 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1739 </tr>
1740 <tr class="layout">
1741 <td class="left"><tt>i32 (i32 *) *</tt></td>
1742 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1743 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1744 <tt>i32</tt>.</td>
1745 </tr>
1746 <tr class="layout">
1747 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1748 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1749 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1750 </tr>
1751</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1752
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1753</div>
1754
1755<!-- _______________________________________________________________________ -->
1756<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1757
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1758<div class="doc_text">
1759
1760<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1761<p>A vector type is a simple derived type that represents a vector of elements.
1762 Vector types are used when multiple primitive data are operated in parallel
1763 using a single instruction (SIMD). A vector type requires a size (number of
1764 elements) and an underlying primitive data type. Vectors must have a power
1765 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1766 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1767
1768<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1769<pre>
1770 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1771</pre>
1772
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1773<p>The number of elements is a constant integer value; elementtype may be any
1774 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1775
1776<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1777<table class="layout">
1778 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1779 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1780 <td class="left">Vector of 4 32-bit integer values.</td>
1781 </tr>
1782 <tr class="layout">
1783 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1784 <td class="left">Vector of 8 32-bit floating-point values.</td>
1785 </tr>
1786 <tr class="layout">
1787 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1788 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1789 </tr>
1790</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1791
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1792<p>Note that the code generator does not yet support large vector types to be
1793 used as function return types. The specific limit on how large a vector
1794 return type codegen can currently handle is target-dependent; currently it's
1795 often a few times longer than a hardware vector register.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1796
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1797</div>
1798
1799<!-- _______________________________________________________________________ -->
1800<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1801<div class="doc_text">
1802
1803<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1804<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1805 corresponds (for example) to the C notion of a forward declared structure
1806 type. In LLVM, opaque types can eventually be resolved to any type (not just
1807 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1808
1809<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1810<pre>
1811 opaque
1812</pre>
1813
1814<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1815<table class="layout">
1816 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1817 <td class="left"><tt>opaque</tt></td>
1818 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1819 </tr>
1820</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1821
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1822</div>
1823
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1824<!-- ======================================================================= -->
1825<div class="doc_subsection">
1826 <a name="t_uprefs">Type Up-references</a>
1827</div>
1828
1829<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1830
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1831<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1832<p>An "up reference" allows you to refer to a lexically enclosing type without
1833 requiring it to have a name. For instance, a structure declaration may
1834 contain a pointer to any of the types it is lexically a member of. Example
1835 of up references (with their equivalent as named type declarations)
1836 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1837
1838<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1839 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1840 { \2 }* %y = type { %y }*
1841 \1* %z = type %z*
1842</pre>
1843
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1844<p>An up reference is needed by the asmprinter for printing out cyclic types
1845 when there is no declared name for a type in the cycle. Because the
1846 asmprinter does not want to print out an infinite type string, it needs a
1847 syntax to handle recursive types that have no names (all names are optional
1848 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1849
1850<h5>Syntax:</h5>
1851<pre>
1852 \&lt;level&gt;
1853</pre>
1854
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1855<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]1856
1857<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1858<table class="layout">
1859 <tr class="layout">
1860 <td class="left"><tt>\1*</tt></td>
1861 <td class="left">Self-referential pointer.</td>
1862 </tr>
1863 <tr class="layout">
1864 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1865 <td class="left">Recursive structure where the upref refers to the out-most
1866 structure.</td>
1867 </tr>
1868</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1869
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1870</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1871
1872<!-- *********************************************************************** -->
1873<div class="doc_section"> <a name="constants">Constants</a> </div>
1874<!-- *********************************************************************** -->
1875
1876<div class="doc_text">
1877
1878<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1879 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1880
1881</div>
1882
1883<!-- ======================================================================= -->
1884<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1885
1886<div class="doc_text">
1887
1888<dl>
1889 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1890 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1891 constants of the <tt><a href="#t_primitive">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1892
1893 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1894 <dd>Standard integers (such as '4') are constants of
1895 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1896 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1897
1898 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1899 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1900 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1901 notation (see below). The assembler requires the exact decimal value of a
1902 floating-point constant. For example, the assembler accepts 1.25 but
1903 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1904 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1905
1906 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1907 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1908 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1909</dl>
1910
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1911<p>The one non-intuitive notation for constants is the hexadecimal form of
1912 floating point constants. For example, the form '<tt>double
1913 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1914 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1915 constants are required (and the only time that they are generated by the
1916 disassembler) is when a floating point constant must be emitted but it cannot
1917 be represented as a decimal floating point number in a reasonable number of
1918 digits. For example, NaN's, infinities, and other special values are
1919 represented in their IEEE hexadecimal format so that assembly and disassembly
1920 do not cause any bits to change in the constants.</p>
1921
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1922<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1923 represented using the 16-digit form shown above (which matches the IEEE754
1924 representation for double); float values must, however, be exactly
1925 representable as IEE754 single precision. Hexadecimal format is always used
1926 for long double, and there are three forms of long double. The 80-bit format
1927 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1928 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1929 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1930 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1931 currently supported target uses this format. Long doubles will only work if
1932 they match the long double format on your target. All hexadecimal formats
1933 are big-endian (sign bit at the left).</p>
1934
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1935</div>
1936
1937<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1938<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]1939<a name="aggregateconstants"></a> <!-- old anchor -->
1940<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1941</div>
1942
1943<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1944
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1945<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1946 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1947
1948<dl>
1949 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1950 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1951 type definitions (a comma separated list of elements, surrounded by braces
1952 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1953 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1954 Structure constants must have <a href="#t_struct">structure type</a>, and
1955 the number and types of elements must match those specified by the
1956 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1957
1958 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1959 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1960 definitions (a comma separated list of elements, surrounded by square
1961 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1962 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1963 the number and types of elements must match those specified by the
1964 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1965
1966 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1967 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1968 definitions (a comma separated list of elements, surrounded by
1969 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1970 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1971 have <a href="#t_vector">vector type</a>, and the number and types of
1972 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1973
1974 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1975 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1976 value to zero of <em>any</em> type, including scalar and aggregate types.
1977 This is often used to avoid having to print large zero initializers
1978 (e.g. for large arrays) and is always exactly equivalent to using explicit
1979 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1980
1981 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]1982 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1983 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1984 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1985 be interpreted as part of the instruction stream, metadata is a place to
1986 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1987</dl>
1988
1989</div>
1990
1991<!-- ======================================================================= -->
1992<div class="doc_subsection">
1993 <a name="globalconstants">Global Variable and Function Addresses</a>
1994</div>
1995
1996<div class="doc_text">
1997
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1998<p>The addresses of <a href="#globalvars">global variables</a>
1999 and <a href="#functionstructure">functions</a> are always implicitly valid
2000 (link-time) constants. These constants are explicitly referenced when
2001 the <a href="#identifiers">identifier for the global</a> is used and always
2002 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2003 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2004
2005<div class="doc_code">
2006<pre>
2007@X = global i32 17
2008@Y = global i32 42
2009@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2010</pre>
2011</div>
2012
2013</div>
2014
2015<!-- ======================================================================= -->
2016<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2017<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2018
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2019<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
2020 indicates that the user of the value may recieve an unspecified bit-pattern.
2021 Undefined values may be of any type (other than label or void) and be used
2022 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2023
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2024<p>Undefined values are useful, because it indicates to the compiler that the
2025 program is well defined no matter what value is used. This gives the
2026 compiler more freedom to optimize. Here are some examples of (potentially
2027 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2028
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2029
2030<div class="doc_code">
2031<pre>
2032 %A = add %X, undef
2033 %B = sub %X, undef
2034 %C = xor %X, undef
2035Safe:
2036 %A = undef
2037 %B = undef
2038 %C = undef
2039</pre>
2040</div>
2041
2042<p>This is safe because all of the output bits are affected by the undef bits.
2043Any output bit can have a zero or one depending on the input bits.</p>
2044
2045<div class="doc_code">
2046<pre>
2047 %A = or %X, undef
2048 %B = and %X, undef
2049Safe:
2050 %A = -1
2051 %B = 0
2052Unsafe:
2053 %A = undef
2054 %B = undef
2055</pre>
2056</div>
2057
2058<p>These logical operations have bits that are not always affected by the input.
2059For example, if "%X" has a zero bit, then the output of the 'and' operation will
2060always be a zero, no matter what the corresponding bit from the undef is. As
2061such, it is unsafe to optimizer or assume that the result of the and is undef.
2062However, it is safe to assume that all bits of the undef are 0, and optimize the
2063and to 0. Likewise, it is safe to assume that all the bits of the undef operand
2064to the or could be set, allowing the or to be folded to -1.</p>
2065
2066<div class="doc_code">
2067<pre>
2068 %A = select undef, %X, %Y
2069 %B = select undef, 42, %Y
2070 %C = select %X, %Y, undef
2071Safe:
2072 %A = %X (or %Y)
2073 %B = 42 (or %Y)
2074 %C = %Y
2075Unsafe:
2076 %A = undef
2077 %B = undef
2078 %C = undef
2079</pre>
2080</div>
2081
2082<p>This set of examples show that undefined select (and conditional branch)
2083conditions can go "either way" but they have to come from one of the two
2084operands. In the %A example, if %X and %Y were both known to have a clear low
2085bit, then %A would have to have a cleared low bit. However, in the %C example,
2086the optimizer is allowed to assume that the undef operand could be the same as
2087%Y, allowing the whole select to be eliminated.</p>
2088
2089
2090<div class="doc_code">
2091<pre>
2092 %A = xor undef, undef
2093
2094 %B = undef
2095 %C = xor %B, %B
2096
2097 %D = undef
2098 %E = icmp lt %D, 4
2099 %F = icmp gte %D, 4
2100
2101Safe:
2102 %A = undef
2103 %B = undef
2104 %C = undef
2105 %D = undef
2106 %E = undef
2107 %F = undef
2108</pre>
2109</div>
2110
2111<p>This example points out that two undef operands are not necessarily the same.
2112This can be surprising to people (and also matches C semantics) where they
2113assume that "X^X" is always zero, even if X is undef. This isn't true for a
2114number of reasons, but the short answer is that an undef "variable" can
2115arbitrarily change its value over its "live range". This is true because the
2116"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2117logically read from arbitrary registers that happen to be around when needed,
2118so the value is not neccesarily consistent over time. In fact, %A and %C need
2119to have the same semantics of the core LLVM "replace all uses with" concept
2120would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2121
2122<div class="doc_code">
2123<pre>
2124 %A = fdiv undef, %X
2125 %B = fdiv %X, undef
2126Safe:
2127 %A = undef
2128b: unreachable
2129</pre>
2130</div>
2131
2132<p>These examples show the crucial difference between an <em>undefined
2133value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2134allowed to have an arbitrary bit-pattern. This means that the %A operation
2135can be constant folded to undef because the undef could be an SNaN, and fdiv is
2136not (currently) defined on SNaN's. However, in the second example, we can make
2137a more aggressive assumption: because the undef is allowed to be an arbitrary
2138value, we are allowed to assume that it could be zero. Since a divide by zero
2139is has <em>undefined behavior</em>, we are allowed to assume that the operation
2140does not execute at all. This allows us to delete the divide and all code after
2141it: since the undefined operation "can't happen", the optimizer can assume that
2142it occurs in dead code.
2143</p>
2144
2145<div class="doc_code">
2146<pre>
2147a: store undef -> %X
2148b: store %X -> undef
2149Safe:
2150a: &lt;deleted&gt;
2151b: unreachable
2152</pre>
2153</div>
2154
2155<p>These examples reiterate the fdiv example: a store "of" an undefined value
2156can be assumed to not have any effect: we can assume that the value is
2157overwritten with bits that happen to match what was already there. However, a
2158store "to" an undefined location could clobber arbitrary memory, therefore, it
2159has undefined behavior.</p>
2160
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2161</div>
2162
2163<!-- ======================================================================= -->
2164<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2165</div>
2166
2167<div class="doc_text">
2168
2169<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2170 to be used as constants. Constant expressions may be of
2171 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2172 operation that does not have side effects (e.g. load and call are not
2173 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2174
2175<dl>
2176 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2177 <dd>Truncate a constant to another type. The bit size of CST must be larger
2178 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2179
2180 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2181 <dd>Zero extend a constant to another type. The bit size of CST must be
2182 smaller or equal to the bit size of TYPE. Both types must be
2183 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2184
2185 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2186 <dd>Sign extend a constant to another type. The bit size of CST must be
2187 smaller or equal to the bit size of TYPE. Both types must be
2188 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2189
2190 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2191 <dd>Truncate a floating point constant to another floating point type. The
2192 size of CST must be larger than the size of TYPE. Both types must be
2193 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2194
2195 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2196 <dd>Floating point extend a constant to another type. The size of CST must be
2197 smaller or equal to the size of TYPE. Both types must be floating
2198 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2199
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2200 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2201 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2202 constant. TYPE must be a scalar or vector integer type. CST must be of
2203 scalar or vector floating point type. Both CST and TYPE must be scalars,
2204 or vectors of the same number of elements. If the value won't fit in the
2205 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2206
2207 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2208 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2209 constant. TYPE must be a scalar or vector integer type. CST must be of
2210 scalar or vector floating point type. Both CST and TYPE must be scalars,
2211 or vectors of the same number of elements. If the value won't fit in the
2212 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2213
2214 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2215 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2216 constant. TYPE must be a scalar or vector floating point type. CST must be
2217 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2218 vectors of the same number of elements. If the value won't fit in the
2219 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2220
2221 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2222 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2223 constant. TYPE must be a scalar or vector floating point type. CST must be
2224 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2225 vectors of the same number of elements. If the value won't fit in the
2226 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2227
2228 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2229 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2230 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2231 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2232 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2233
2234 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2235 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2236 type. CST must be of integer type. The CST value is zero extended,
2237 truncated, or unchanged to make it fit in a pointer size. This one is
2238 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2239
2240 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2241 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2242 are the same as those for the <a href="#i_bitcast">bitcast
2243 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2244
2245 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2246 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2247 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2248 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2249 instruction, the index list may have zero or more indexes, which are
2250 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2251
2252 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2253 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2254
2255 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2256 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2257
2258 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2259 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2260
2261 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2262 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2263 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2264
2265 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2266 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2267 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2268
2269 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2270 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2271 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2272
2273 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2274 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2275 be any of the <a href="#binaryops">binary</a>
2276 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2277 on operands are the same as those for the corresponding instruction
2278 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2279</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2280
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2281</div>
2282
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2283<!-- ======================================================================= -->
2284<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2285</div>
2286
2287<div class="doc_text">
2288
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2289<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2290 stream without affecting the behaviour of the program. There are two
2291 metadata primitives, strings and nodes. All metadata has the
2292 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2293 point ('<tt>!</tt>').</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2294
2295<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2296 any character by escaping non-printable characters with "\xx" where "xx" is
2297 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2298
2299<p>Metadata nodes are represented with notation similar to structure constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2300 (a comma separated list of elements, surrounded by braces and preceeded by an
2301 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2302 10}</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2303
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2304<p>A metadata node will attempt to track changes to the values it holds. In the
2305 event that a value is deleted, it will be replaced with a typeless
2306 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2307
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2308<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2309 the program that isn't available in the instructions, or that isn't easily
2310 computable. Similarly, the code generator may expect a certain metadata
2311 format to be used to express debugging information.</p>
2312
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2313</div>
2314
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2315<!-- *********************************************************************** -->
2316<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2317<!-- *********************************************************************** -->
2318
2319<!-- ======================================================================= -->
2320<div class="doc_subsection">
2321<a name="inlineasm">Inline Assembler Expressions</a>
2322</div>
2323
2324<div class="doc_text">
2325
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2326<p>LLVM supports inline assembler expressions (as opposed
2327 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2328 a special value. This value represents the inline assembler as a string
2329 (containing the instructions to emit), a list of operand constraints (stored
2330 as a string), and a flag that indicates whether or not the inline asm
2331 expression has side effects. An example inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2332
2333<div class="doc_code">
2334<pre>
2335i32 (i32) asm "bswap $0", "=r,r"
2336</pre>
2337</div>
2338
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2339<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2340 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2341 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2342
2343<div class="doc_code">
2344<pre>
2345%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2346</pre>
2347</div>
2348
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2349<p>Inline asms with side effects not visible in the constraint list must be
2350 marked as having side effects. This is done through the use of the
2351 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2352
2353<div class="doc_code">
2354<pre>
2355call void asm sideeffect "eieio", ""()
2356</pre>
2357</div>
2358
2359<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2360 documented here. Constraints on what can be done (e.g. duplication, moving,
2361 etc need to be documented). This is probably best done by reference to
2362 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2363
2364</div>
2365
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2366
2367<!-- *********************************************************************** -->
2368<div class="doc_section">
2369 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2370</div>
2371<!-- *********************************************************************** -->
2372
2373<p>LLVM has a number of "magic" global variables that contain data that affect
2374code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2375of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2376section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2377by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2378
2379<!-- ======================================================================= -->
2380<div class="doc_subsection">
2381<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2382</div>
2383
2384<div class="doc_text">
2385
2386<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2387href="#linkage_appending">appending linkage</a>. This array contains a list of
2388pointers to global variables and functions which may optionally have a pointer
2389cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2390
2391<pre>
2392 @X = global i8 4
2393 @Y = global i32 123
2394
2395 @llvm.used = appending global [2 x i8*] [
2396 i8* @X,
2397 i8* bitcast (i32* @Y to i8*)
2398 ], section "llvm.metadata"
2399</pre>
2400
2401<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2402compiler, assembler, and linker are required to treat the symbol as if there is
2403a reference to the global that it cannot see. For example, if a variable has
2404internal linkage and no references other than that from the <tt>@llvm.used</tt>
2405list, it cannot be deleted. This is commonly used to represent references from
2406inline asms and other things the compiler cannot "see", and corresponds to
2407"attribute((used))" in GNU C.</p>
2408
2409<p>On some targets, the code generator must emit a directive to the assembler or
2410object file to prevent the assembler and linker from molesting the symbol.</p>
2411
2412</div>
2413
2414<!-- ======================================================================= -->
2415<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2416<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2417</div>
2418
2419<div class="doc_text">
2420
2421<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2422<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2423touching the symbol. On targets that support it, this allows an intelligent
2424linker to optimize references to the symbol without being impeded as it would be
2425by <tt>@llvm.used</tt>.</p>
2426
2427<p>This is a rare construct that should only be used in rare circumstances, and
2428should not be exposed to source languages.</p>
2429
2430</div>
2431
2432<!-- ======================================================================= -->
2433<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2434<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2435</div>
2436
2437<div class="doc_text">
2438
2439<p>TODO: Describe this.</p>
2440
2441</div>
2442
2443<!-- ======================================================================= -->
2444<div class="doc_subsection">
2445<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2446</div>
2447
2448<div class="doc_text">
2449
2450<p>TODO: Describe this.</p>
2451
2452</div>
2453
2454
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2455<!-- *********************************************************************** -->
2456<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2457<!-- *********************************************************************** -->
2458
2459<div class="doc_text">
2460
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2461<p>The LLVM instruction set consists of several different classifications of
2462 instructions: <a href="#terminators">terminator
2463 instructions</a>, <a href="#binaryops">binary instructions</a>,
2464 <a href="#bitwiseops">bitwise binary instructions</a>,
2465 <a href="#memoryops">memory instructions</a>, and
2466 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2467
2468</div>
2469
2470<!-- ======================================================================= -->
2471<div class="doc_subsection"> <a name="terminators">Terminator
2472Instructions</a> </div>
2473
2474<div class="doc_text">
2475
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2476<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2477 in a program ends with a "Terminator" instruction, which indicates which
2478 block should be executed after the current block is finished. These
2479 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2480 control flow, not values (the one exception being the
2481 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2482
2483<p>There are six different terminator instructions: the
2484 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2485 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2486 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
2487 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2488 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2489 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2490
2491</div>
2492
2493<!-- _______________________________________________________________________ -->
2494<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2495Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2496
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2497<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2498
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2499<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2500<pre>
2501 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]2502 ret void <i>; Return from void function</i>
2503</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2504
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2505<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2506<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2507 a value) from a function back to the caller.</p>
2508
2509<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2510 value and then causes control flow, and one that just causes control flow to
2511 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2512
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2513<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2514<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2515 return value. The type of the return value must be a
2516 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2517
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2518<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2519 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2520 value or a return value with a type that does not match its type, or if it
2521 has a void return type and contains a '<tt>ret</tt>' instruction with a
2522 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2524<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2525<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2526 the calling function's context. If the caller is a
2527 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2528 instruction after the call. If the caller was an
2529 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2530 the beginning of the "normal" destination block. If the instruction returns
2531 a value, that value shall set the call or invoke instruction's return
2532 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2533
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2534<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2535<pre>
2536 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2537 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2538 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]2539</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2540
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2541<p>Note that the code generator does not yet fully support large
2542 return values. The specific sizes that are currently supported are
2543 dependent on the target. For integers, on 32-bit targets the limit
2544 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2545 For aggregate types, the current limits are dependent on the element
2546 types; for example targets are often limited to 2 total integer
2547 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2548
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2549</div>
2550<!-- _______________________________________________________________________ -->
2551<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2552
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2553<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2554
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2555<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2556<pre>
2557 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]2558</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2559
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2560<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2561<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2562 different basic block in the current function. There are two forms of this
2563 instruction, corresponding to a conditional branch and an unconditional
2564 branch.</p>
2565
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2566<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2567<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2568 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2569 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2570 target.</p>
2571
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2572<h5>Semantics:</h5>
2573<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2574 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2575 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2576 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2577
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2578<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2579<pre>
2580Test:
2581 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2582 br i1 %cond, label %IfEqual, label %IfUnequal
2583IfEqual:
2584 <a href="#i_ret">ret</a> i32 1
2585IfUnequal:
2586 <a href="#i_ret">ret</a> i32 0
2587</pre>
2588
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2589</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2590
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2591<!-- _______________________________________________________________________ -->
2592<div class="doc_subsubsection">
2593 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2594</div>
2595
2596<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2597
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2598<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2599<pre>
2600 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2601</pre>
2602
2603<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2604<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]2605 several different places. It is a generalization of the '<tt>br</tt>'
2606 instruction, allowing a branch to occur to one of many possible
2607 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2608
2609<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2610<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2611 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2612 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2613 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2614
2615<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2616<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2617 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2618 is searched for the given value. If the value is found, control flow is
2619 transfered to the corresponding destination; otherwise, control flow is
2620 transfered to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2621
2622<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2623<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2624 <tt>switch</tt> instruction, this instruction may be code generated in
2625 different ways. For example, it could be generated as a series of chained
2626 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2627
2628<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2629<pre>
2630 <i>; Emulate a conditional br instruction</i>
2631 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2632 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2633
2634 <i>; Emulate an unconditional br instruction</i>
2635 switch i32 0, label %dest [ ]
2636
2637 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2638 switch i32 %val, label %otherwise [ i32 0, label %onzero
2639 i32 1, label %onone
2640 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2641</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2642
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2643</div>
2644
2645<!-- _______________________________________________________________________ -->
2646<div class="doc_subsubsection">
2647 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2648</div>
2649
2650<div class="doc_text">
2651
2652<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2653<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2654 &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]2655 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2656</pre>
2657
2658<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2659<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2660 function, with the possibility of control flow transfer to either the
2661 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2662 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2663 control flow will return to the "normal" label. If the callee (or any
2664 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2665 instruction, control is interrupted and continued at the dynamically nearest
2666 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2667
2668<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2669<p>This instruction requires several arguments:</p>
2670
2671<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2672 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2673 convention</a> the call should use. If none is specified, the call
2674 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2675
2676 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2677 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2678 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2679
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2680 <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]2681 function value being invoked. In most cases, this is a direct function
2682 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2683 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2684
2685 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2686 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2687
2688 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2689 signature argument types. If the function signature indicates the
2690 function accepts a variable number of arguments, the extra arguments can
2691 be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2692
2693 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2694 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2695
2696 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2697 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2698
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2699 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2700 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2701 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2702</ol>
2703
2704<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2705<p>This instruction is designed to operate as a standard
2706 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2707 primary difference is that it establishes an association with a label, which
2708 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2709
2710<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2711 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2712 exception. Additionally, this is important for implementation of
2713 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2714
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2715<p>For the purposes of the SSA form, the definition of the value returned by the
2716 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2717 block to the "normal" label. If the callee unwinds then no return value is
2718 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2719
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2720<h5>Example:</h5>
2721<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2722 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2723 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2724 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2725 unwind label %TestCleanup <i>; {i32}:retval set</i>
2726</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2727
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2728</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2729
2730<!-- _______________________________________________________________________ -->
2731
2732<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2733Instruction</a> </div>
2734
2735<div class="doc_text">
2736
2737<h5>Syntax:</h5>
2738<pre>
2739 unwind
2740</pre>
2741
2742<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2743<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2744 at the first callee in the dynamic call stack which used
2745 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2746 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2747
2748<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2749<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2750 immediately halt. The dynamic call stack is then searched for the
2751 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2752 Once found, execution continues at the "exceptional" destination block
2753 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2754 instruction in the dynamic call chain, undefined behavior results.</p>
2755
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2756</div>
2757
2758<!-- _______________________________________________________________________ -->
2759
2760<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2761Instruction</a> </div>
2762
2763<div class="doc_text">
2764
2765<h5>Syntax:</h5>
2766<pre>
2767 unreachable
2768</pre>
2769
2770<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2771<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2772 instruction is used to inform the optimizer that a particular portion of the
2773 code is not reachable. This can be used to indicate that the code after a
2774 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2775
2776<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2777<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2778
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2779</div>
2780
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2781<!-- ======================================================================= -->
2782<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2783
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2784<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2785
2786<p>Binary operators are used to do most of the computation in a program. They
2787 require two operands of the same type, execute an operation on them, and
2788 produce a single value. The operands might represent multiple data, as is
2789 the case with the <a href="#t_vector">vector</a> data type. The result value
2790 has the same type as its operands.</p>
2791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2792<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2793
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2794</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2795
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2796<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2797<div class="doc_subsubsection">
2798 <a name="i_add">'<tt>add</tt>' Instruction</a>
2799</div>
2800
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2801<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2803<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2804<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2805 &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]2806 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2807 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2808 &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]2809</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2810
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2811<h5>Overview:</h5>
2812<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2813
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2814<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2815<p>The two arguments to the '<tt>add</tt>' instruction must
2816 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2817 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2818
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2819<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2820<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2821
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2822<p>If the sum has unsigned overflow, the result returned is the mathematical
2823 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]2824
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2825<p>Because LLVM integers use a two's complement representation, this instruction
2826 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2827
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2828<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2829 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2830 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2831 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2832
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2833<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2834<pre>
2835 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2836</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2838</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2839
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2840<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2841<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2842 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2843</div>
2844
2845<div class="doc_text">
2846
2847<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2848<pre>
2849 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2850</pre>
2851
2852<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2853<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2854
2855<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2856<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2857 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2858 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2859
2860<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2861<p>The value produced is the floating point sum of the two operands.</p>
2862
2863<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2864<pre>
2865 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2866</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2867
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2868</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2869
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2870<!-- _______________________________________________________________________ -->
2871<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2872 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2873</div>
2874
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2875<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2876
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2877<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2878<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2879 &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]2880 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2881 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2882 &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]2883</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2884
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2885<h5>Overview:</h5>
2886<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2887 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2888
2889<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2890 '<tt>neg</tt>' instruction present in most other intermediate
2891 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2892
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2893<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2894<p>The two arguments to the '<tt>sub</tt>' instruction must
2895 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2896 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2897
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2898<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2899<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2900
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2901<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2902 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2903 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2904
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2905<p>Because LLVM integers use a two's complement representation, this instruction
2906 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2907
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2908<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2909 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2910 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2911 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2912
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2913<h5>Example:</h5>
2914<pre>
2915 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2916 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2917</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2918
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2919</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2920
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2921<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2922<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2923 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2924</div>
2925
2926<div class="doc_text">
2927
2928<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2929<pre>
2930 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2931</pre>
2932
2933<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2934<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2935 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2936
2937<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2938 '<tt>fneg</tt>' instruction present in most other intermediate
2939 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2940
2941<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2942<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2943 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2944 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2945
2946<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2947<p>The value produced is the floating point difference of the two operands.</p>
2948
2949<h5>Example:</h5>
2950<pre>
2951 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2952 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2953</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2954
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2955</div>
2956
2957<!-- _______________________________________________________________________ -->
2958<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2959 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2960</div>
2961
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2962<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2963
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2964<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2965<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2966 &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]2967 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2968 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2969 &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]2970</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2971
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2972<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2973<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2974
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2975<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2976<p>The two arguments to the '<tt>mul</tt>' instruction must
2977 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2978 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2979
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2980<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2981<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2982
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2983<p>If the result of the multiplication has unsigned overflow, the result
2984 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
2985 width of the result.</p>
2986
2987<p>Because LLVM integers use a two's complement representation, and the result
2988 is the same width as the operands, this instruction returns the correct
2989 result for both signed and unsigned integers. If a full product
2990 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
2991 be sign-extended or zero-extended as appropriate to the width of the full
2992 product.</p>
2993
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2994<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2995 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2996 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
2997 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2998
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2999<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3000<pre>
3001 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3002</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3003
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3004</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3005
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3006<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3007<div class="doc_subsubsection">
3008 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3009</div>
3010
3011<div class="doc_text">
3012
3013<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3014<pre>
3015 &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]3016</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3017
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3018<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3019<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3020
3021<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3022<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3023 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3024 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3025
3026<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3027<p>The value produced is the floating point product of the two operands.</p>
3028
3029<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3030<pre>
3031 &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]3032</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3033
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3034</div>
3035
3036<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3037<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3038</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3039
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3040<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3041
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3042<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3043<pre>
3044 &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]3045</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3046
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3047<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3048<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3049
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3050<h5>Arguments:</h5>
3051<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3052 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3053 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3054
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3055<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3056<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3057
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3058<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3059 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3060
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3061<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3062
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3063<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3064<pre>
3065 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3066</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3067
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3068</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3069
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3070<!-- _______________________________________________________________________ -->
3071<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3072</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3073
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3074<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3075
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3076<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3077<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3078 &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]3079 &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]3080</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3081
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3082<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3083<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3084
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3085<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3086<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3087 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3088 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3089
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3090<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3091<p>The value produced is the signed integer quotient of the two operands rounded
3092 towards zero.</p>
3093
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3094<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3095 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3096
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3097<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3098 undefined behavior; this is a rare case, but can occur, for example, by doing
3099 a 32-bit division of -2147483648 by -1.</p>
3100
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3101<p>If the <tt>exact</tt> keyword is present, the result value of the
3102 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3103 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3104
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3105<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3106<pre>
3107 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3108</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3109
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3110</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3111
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3112<!-- _______________________________________________________________________ -->
3113<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3114Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3115
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3116<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3117
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3118<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3119<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3120 &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]3121</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3122
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3123<h5>Overview:</h5>
3124<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3125
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3126<h5>Arguments:</h5>
3127<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3128 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3129 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3130
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3131<h5>Semantics:</h5>
3132<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3133
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3134<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3135<pre>
3136 &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]3137</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3138
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3139</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3140
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3141<!-- _______________________________________________________________________ -->
3142<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3143</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3144
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3145<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3146
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3147<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3148<pre>
3149 &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]3150</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3151
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3152<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3153<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3154 division of its two arguments.</p>
3155
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3156<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3157<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3158 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3159 values. Both arguments must have identical types.</p>
3160
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3161<h5>Semantics:</h5>
3162<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3163 This instruction always performs an unsigned division to get the
3164 remainder.</p>
3165
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3166<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3167 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3168
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3169<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3170
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3171<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3172<pre>
3173 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3174</pre>
3175
3176</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3177
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3178<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3179<div class="doc_subsubsection">
3180 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3181</div>
3182
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3183<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3184
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3185<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3186<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3187 &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]3188</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3189
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3190<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3191<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3192 division of its two operands. This instruction can also take
3193 <a href="#t_vector">vector</a> versions of the values in which case the
3194 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3195
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3196<h5>Arguments:</h5>
3197<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3198 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3199 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3200
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3201<h5>Semantics:</h5>
3202<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3203 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3204 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3205 a value. For more information about the difference,
3206 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3207 Math Forum</a>. For a table of how this is implemented in various languages,
3208 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3209 Wikipedia: modulo operation</a>.</p>
3210
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3211<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3212 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3213
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3214<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3215 Overflow also leads to undefined behavior; this is a rare case, but can
3216 occur, for example, by taking the remainder of a 32-bit division of
3217 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3218 lets srem be implemented using instructions that return both the result of
3219 the division and the remainder.)</p>
3220
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3221<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3222<pre>
3223 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3224</pre>
3225
3226</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3228<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3229<div class="doc_subsubsection">
3230 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3231
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3232<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3233
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3234<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3235<pre>
3236 &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]3237</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3238
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3239<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3240<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3241 its two operands.</p>
3242
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3243<h5>Arguments:</h5>
3244<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3245 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3246 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3247
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3248<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3249<p>This instruction returns the <i>remainder</i> of a division. The remainder
3250 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3251
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3252<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3253<pre>
3254 &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]3255</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3256
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3257</div>
3258
3259<!-- ======================================================================= -->
3260<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3261Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3262
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3263<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3264
3265<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3266 program. They are generally very efficient instructions and can commonly be
3267 strength reduced from other instructions. They require two operands of the
3268 same type, execute an operation on them, and produce a single value. The
3269 resulting value is the same type as its operands.</p>
3270
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3271</div>
3272
3273<!-- _______________________________________________________________________ -->
3274<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3275Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3276
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3277<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3279<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3280<pre>
3281 &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]3282</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3283
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3284<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3285<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3286 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3287
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3288<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3289<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3290 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3291 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3292
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3293<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3294<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3295 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3296 is (statically or dynamically) negative or equal to or larger than the number
3297 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3298 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3299 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3300
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3301<h5>Example:</h5>
3302<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3303 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3304 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3305 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3306 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3307 &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]3308</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3309
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3310</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3311
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3312<!-- _______________________________________________________________________ -->
3313<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3314Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3315
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3316<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3317
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3318<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3319<pre>
3320 &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]3321</pre>
3322
3323<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3324<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3325 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3326
3327<h5>Arguments:</h5>
3328<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3329 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3330 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3331
3332<h5>Semantics:</h5>
3333<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3334 significant bits of the result will be filled with zero bits after the shift.
3335 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3336 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3337 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3338 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3339
3340<h5>Example:</h5>
3341<pre>
3342 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3343 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3344 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3345 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3346 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3347 &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]3348</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3349
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3350</div>
3351
3352<!-- _______________________________________________________________________ -->
3353<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3354Instruction</a> </div>
3355<div class="doc_text">
3356
3357<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3358<pre>
3359 &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]3360</pre>
3361
3362<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3363<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3364 operand shifted to the right a specified number of bits with sign
3365 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3366
3367<h5>Arguments:</h5>
3368<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3369 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3370 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3371
3372<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3373<p>This instruction always performs an arithmetic shift right operation, The
3374 most significant bits of the result will be filled with the sign bit
3375 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3376 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3377 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3378 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3379
3380<h5>Example:</h5>
3381<pre>
3382 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3383 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3384 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3385 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3386 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3387 &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]3388</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3390</div>
3391
3392<!-- _______________________________________________________________________ -->
3393<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3394Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3395
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3396<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3397
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3398<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3399<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3400 &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]3401</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3402
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3403<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3404<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3405 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3406
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3407<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3408<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3409 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3410 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3411
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3412<h5>Semantics:</h5>
3413<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3414
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3415<table border="1" cellspacing="0" cellpadding="4">
3416 <tbody>
3417 <tr>
3418 <td>In0</td>
3419 <td>In1</td>
3420 <td>Out</td>
3421 </tr>
3422 <tr>
3423 <td>0</td>
3424 <td>0</td>
3425 <td>0</td>
3426 </tr>
3427 <tr>
3428 <td>0</td>
3429 <td>1</td>
3430 <td>0</td>
3431 </tr>
3432 <tr>
3433 <td>1</td>
3434 <td>0</td>
3435 <td>0</td>
3436 </tr>
3437 <tr>
3438 <td>1</td>
3439 <td>1</td>
3440 <td>1</td>
3441 </tr>
3442 </tbody>
3443</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3444
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3445<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3446<pre>
3447 &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]3448 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3449 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3450</pre>
3451</div>
3452<!-- _______________________________________________________________________ -->
3453<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3454
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3455<div class="doc_text">
3456
3457<h5>Syntax:</h5>
3458<pre>
3459 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3460</pre>
3461
3462<h5>Overview:</h5>
3463<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3464 two operands.</p>
3465
3466<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3467<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3468 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3469 values. Both arguments must have identical types.</p>
3470
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3471<h5>Semantics:</h5>
3472<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3473
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3474<table border="1" cellspacing="0" cellpadding="4">
3475 <tbody>
3476 <tr>
3477 <td>In0</td>
3478 <td>In1</td>
3479 <td>Out</td>
3480 </tr>
3481 <tr>
3482 <td>0</td>
3483 <td>0</td>
3484 <td>0</td>
3485 </tr>
3486 <tr>
3487 <td>0</td>
3488 <td>1</td>
3489 <td>1</td>
3490 </tr>
3491 <tr>
3492 <td>1</td>
3493 <td>0</td>
3494 <td>1</td>
3495 </tr>
3496 <tr>
3497 <td>1</td>
3498 <td>1</td>
3499 <td>1</td>
3500 </tr>
3501 </tbody>
3502</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3503
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3504<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3505<pre>
3506 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3507 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3508 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3509</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3510
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3511</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3512
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3513<!-- _______________________________________________________________________ -->
3514<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3515Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3516
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3517<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3518
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3519<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3520<pre>
3521 &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]3522</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3524<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3525<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3526 its two operands. The <tt>xor</tt> is used to implement the "one's
3527 complement" operation, which is the "~" operator in C.</p>
3528
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3529<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3530<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3531 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3532 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3533
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3534<h5>Semantics:</h5>
3535<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3536
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3537<table border="1" cellspacing="0" cellpadding="4">
3538 <tbody>
3539 <tr>
3540 <td>In0</td>
3541 <td>In1</td>
3542 <td>Out</td>
3543 </tr>
3544 <tr>
3545 <td>0</td>
3546 <td>0</td>
3547 <td>0</td>
3548 </tr>
3549 <tr>
3550 <td>0</td>
3551 <td>1</td>
3552 <td>1</td>
3553 </tr>
3554 <tr>
3555 <td>1</td>
3556 <td>0</td>
3557 <td>1</td>
3558 </tr>
3559 <tr>
3560 <td>1</td>
3561 <td>1</td>
3562 <td>0</td>
3563 </tr>
3564 </tbody>
3565</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3566
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3567<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3568<pre>
3569 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3570 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3571 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3572 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3573</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3574
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3575</div>
3576
3577<!-- ======================================================================= -->
3578<div class="doc_subsection">
3579 <a name="vectorops">Vector Operations</a>
3580</div>
3581
3582<div class="doc_text">
3583
3584<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3585 target-independent manner. These instructions cover the element-access and
3586 vector-specific operations needed to process vectors effectively. While LLVM
3587 does directly support these vector operations, many sophisticated algorithms
3588 will want to use target-specific intrinsics to take full advantage of a
3589 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3590
3591</div>
3592
3593<!-- _______________________________________________________________________ -->
3594<div class="doc_subsubsection">
3595 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3596</div>
3597
3598<div class="doc_text">
3599
3600<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3601<pre>
3602 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3603</pre>
3604
3605<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3606<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3607 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3608
3609
3610<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3611<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3612 of <a href="#t_vector">vector</a> type. The second operand is an index
3613 indicating the position from which to extract the element. The index may be
3614 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3615
3616<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3617<p>The result is a scalar of the same type as the element type of
3618 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3619 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3620 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3621
3622<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3623<pre>
3624 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3625</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3626
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3627</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3628
3629<!-- _______________________________________________________________________ -->
3630<div class="doc_subsubsection">
3631 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3632</div>
3633
3634<div class="doc_text">
3635
3636<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3637<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3638 &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]3639</pre>
3640
3641<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3642<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3643 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3644
3645<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3646<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3647 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3648 whose type must equal the element type of the first operand. The third
3649 operand is an index indicating the position at which to insert the value.
3650 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3651
3652<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3653<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3654 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3655 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3656 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3657
3658<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3659<pre>
3660 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3661</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3663</div>
3664
3665<!-- _______________________________________________________________________ -->
3666<div class="doc_subsubsection">
3667 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3668</div>
3669
3670<div class="doc_text">
3671
3672<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3673<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3674 &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]3675</pre>
3676
3677<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3678<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3679 from two input vectors, returning a vector with the same element type as the
3680 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3681
3682<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3683<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3684 with types that match each other. The third argument is a shuffle mask whose
3685 element type is always 'i32'. The result of the instruction is a vector
3686 whose length is the same as the shuffle mask and whose element type is the
3687 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3688
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3689<p>The shuffle mask operand is required to be a constant vector with either
3690 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3691
3692<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3693<p>The elements of the two input vectors are numbered from left to right across
3694 both of the vectors. The shuffle mask operand specifies, for each element of
3695 the result vector, which element of the two input vectors the result element
3696 gets. The element selector may be undef (meaning "don't care") and the
3697 second operand may be undef if performing a shuffle from only one vector.</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 = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3702 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3703 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3704 &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]3705 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3706 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3707 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3708 &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]3709</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3710
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3711</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3712
3713<!-- ======================================================================= -->
3714<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3715 <a name="aggregateops">Aggregate Operations</a>
3716</div>
3717
3718<div class="doc_text">
3719
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3720<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3721
3722</div>
3723
3724<!-- _______________________________________________________________________ -->
3725<div class="doc_subsubsection">
3726 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3727</div>
3728
3729<div class="doc_text">
3730
3731<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3732<pre>
3733 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3734</pre>
3735
3736<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3737<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3738 or array element from an aggregate value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3739
3740<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3741<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3742 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3743 operands are constant indices to specify which value to extract in a similar
3744 manner as indices in a
3745 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3746
3747<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3748<p>The result is the value at the position in the aggregate specified by the
3749 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3750
3751<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3752<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3753 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3754</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3755
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3756</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3757
3758<!-- _______________________________________________________________________ -->
3759<div class="doc_subsubsection">
3760 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3761</div>
3762
3763<div class="doc_text">
3764
3765<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3766<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3767 &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]3768</pre>
3769
3770<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3771<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3772 array element in an aggregate.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3773
3774
3775<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3776<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3777 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3778 second operand is a first-class value to insert. The following operands are
3779 constant indices indicating the position at which to insert the value in a
3780 similar manner as indices in a
3781 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3782 value to insert must have the same type as the value identified by the
3783 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3784
3785<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3786<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3787 that of <tt>val</tt> except that the value at the position specified by the
3788 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3789
3790<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3791<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3792 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3793</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3794
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3795</div>
3796
3797
3798<!-- ======================================================================= -->
3799<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3800 <a name="memoryops">Memory Access and Addressing Operations</a>
3801</div>
3802
3803<div class="doc_text">
3804
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3805<p>A key design point of an SSA-based representation is how it represents
3806 memory. In LLVM, no memory locations are in SSA form, which makes things
3807 very simple. This section describes how to read, write, allocate, and free
3808 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3809
3810</div>
3811
3812<!-- _______________________________________________________________________ -->
3813<div class="doc_subsubsection">
3814 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3815</div>
3816
3817<div class="doc_text">
3818
3819<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3820<pre>
3821 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3822</pre>
3823
3824<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3825<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3826 returns a pointer to it. The object is always allocated in the generic
3827 address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3828
3829<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3830<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3831 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3832 system and returns a pointer of the appropriate type to the program. If
3833 "NumElements" is specified, it is the number of elements allocated, otherwise
3834 "NumElements" is defaulted to be one. If a constant alignment is specified,
3835 the value result of the allocation is guaranteed to be aligned to at least
3836 that boundary. If not specified, or if zero, the target can choose to align
3837 the allocation on any convenient boundary compatible with the type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3838
3839<p>'<tt>type</tt>' must be a sized type.</p>
3840
3841<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3842<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3843 pointer is returned. The result of a zero byte allocation is undefined. The
3844 result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3845
3846<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3847<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3848 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3849
3850 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3851 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3852 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3853 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3854 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3855</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3856
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3857<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3858
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3859</div>
3860
3861<!-- _______________________________________________________________________ -->
3862<div class="doc_subsubsection">
3863 <a name="i_free">'<tt>free</tt>' Instruction</a>
3864</div>
3865
3866<div class="doc_text">
3867
3868<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3869<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3870 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3871</pre>
3872
3873<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3874<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3875 to be reallocated in the future.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3876
3877<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3878<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3879 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3880
3881<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3882<p>Access to the memory pointed to by the pointer is no longer defined after
3883 this instruction executes. If the pointer is null, the operation is a
3884 noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3885
3886<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3887<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3888 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3889 free [4 x i8]* %array
3890</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3891
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3892</div>
3893
3894<!-- _______________________________________________________________________ -->
3895<div class="doc_subsubsection">
3896 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3897</div>
3898
3899<div class="doc_text">
3900
3901<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3902<pre>
3903 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3904</pre>
3905
3906<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3907<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3908 currently executing function, to be automatically released when this function
3909 returns to its caller. The object is always allocated in the generic address
3910 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3911
3912<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3913<p>The '<tt>alloca</tt>' instruction
3914 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3915 runtime stack, returning a pointer of the appropriate type to the program.
3916 If "NumElements" is specified, it is the number of elements allocated,
3917 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3918 specified, the value result of the allocation is guaranteed to be aligned to
3919 at least that boundary. If not specified, or if zero, the target can choose
3920 to align the allocation on any convenient boundary compatible with the
3921 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3922
3923<p>'<tt>type</tt>' may be any sized type.</p>
3924
3925<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3926<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3927 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3928 memory is automatically released when the function returns. The
3929 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3930 variables that must have an address available. When the function returns
3931 (either with the <tt><a href="#i_ret">ret</a></tt>
3932 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3933 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3934
3935<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3936<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3937 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3938 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3939 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3940 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3941</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3942
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3943</div>
3944
3945<!-- _______________________________________________________________________ -->
3946<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3947Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3948
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3949<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3950
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3951<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3952<pre>
3953 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3954 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3955</pre>
3956
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3957<h5>Overview:</h5>
3958<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3959
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3960<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3961<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3962 from which to load. The pointer must point to
3963 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3964 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3965 number or order of execution of this <tt>load</tt> with other
3966 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3967 instructions. </p>
3968
3969<p>The optional constant "align" argument specifies the alignment of the
3970 operation (that is, the alignment of the memory address). A value of 0 or an
3971 omitted "align" argument means that the operation has the preferential
3972 alignment for the target. It is the responsibility of the code emitter to
3973 ensure that the alignment information is correct. Overestimating the
3974 alignment results in an undefined behavior. Underestimating the alignment may
3975 produce less efficient code. An alignment of 1 is always safe.</p>
3976
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3977<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3978<p>The location of memory pointed to is loaded. If the value being loaded is of
3979 scalar type then the number of bytes read does not exceed the minimum number
3980 of bytes needed to hold all bits of the type. For example, loading an
3981 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3982 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3983 is undefined if the value was not originally written using a store of the
3984 same type.</p>
3985
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3986<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3987<pre>
3988 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3989 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3990 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3991</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3992
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3993</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3994
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3995<!-- _______________________________________________________________________ -->
3996<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3997Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3998
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3999<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4000
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4001<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4002<pre>
4003 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]4004 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
4005</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4006
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4007<h5>Overview:</h5>
4008<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4009
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4010<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4011<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4012 and an address at which to store it. The type of the
4013 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4014 the <a href="#t_firstclass">first class</a> type of the
4015 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4016 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4017 or order of execution of this <tt>store</tt> with other
4018 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4019 instructions.</p>
4020
4021<p>The optional constant "align" argument specifies the alignment of the
4022 operation (that is, the alignment of the memory address). A value of 0 or an
4023 omitted "align" argument means that the operation has the preferential
4024 alignment for the target. It is the responsibility of the code emitter to
4025 ensure that the alignment information is correct. Overestimating the
4026 alignment results in an undefined behavior. Underestimating the alignment may
4027 produce less efficient code. An alignment of 1 is always safe.</p>
4028
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4029<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4030<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4031 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4032 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4033 does not exceed the minimum number of bytes needed to hold all bits of the
4034 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4035 writing a value of a type like <tt>i20</tt> with a size that is not an
4036 integral number of bytes, it is unspecified what happens to the extra bits
4037 that do not belong to the type, but they will typically be overwritten.</p>
4038
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4039<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4040<pre>
4041 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4042 store i32 3, i32* %ptr <i>; yields {void}</i>
4043 %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]4044</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4045
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4046</div>
4047
4048<!-- _______________________________________________________________________ -->
4049<div class="doc_subsubsection">
4050 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4051</div>
4052
4053<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4054
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4055<h5>Syntax:</h5>
4056<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4057 &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]4058 &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]4059</pre>
4060
4061<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4062<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4063 subelement of an aggregate data structure. It performs address calculation
4064 only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4065
4066<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4067<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4068 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4069 elements of the aggregate object are indexed. The interpretation of each
4070 index is dependent on the type being indexed into. The first index always
4071 indexes the pointer value given as the first argument, the second index
4072 indexes a value of the type pointed to (not necessarily the value directly
4073 pointed to, since the first index can be non-zero), etc. The first type
4074 indexed into must be a pointer value, subsequent types can be arrays, vectors
4075 and structs. Note that subsequent types being indexed into can never be
4076 pointers, since that would require loading the pointer before continuing
4077 calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4078
4079<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]4080 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4081 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4082 vector, integers of any width are allowed, and they are not required to be
4083 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4084
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4085<p>For example, let's consider a C code fragment and how it gets compiled to
4086 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4087
4088<div class="doc_code">
4089<pre>
4090struct RT {
4091 char A;
4092 int B[10][20];
4093 char C;
4094};
4095struct ST {
4096 int X;
4097 double Y;
4098 struct RT Z;
4099};
4100
4101int *foo(struct ST *s) {
4102 return &amp;s[1].Z.B[5][13];
4103}
4104</pre>
4105</div>
4106
4107<p>The LLVM code generated by the GCC frontend is:</p>
4108
4109<div class="doc_code">
4110<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4111%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4112%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4113
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4114define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4115entry:
4116 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4117 ret i32* %reg
4118}
4119</pre>
4120</div>
4121
4122<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4123<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]4124 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4125 }</tt>' type, a structure. The second index indexes into the third element
4126 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4127 i8 }</tt>' type, another structure. The third index indexes into the second
4128 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4129 array. The two dimensions of the array are subscripted into, yielding an
4130 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4131 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4132
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4133<p>Note that it is perfectly legal to index partially through a structure,
4134 returning a pointer to an inner element. Because of this, the LLVM code for
4135 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4136
4137<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4138 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4139 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4140 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4141 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4142 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4143 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4144 ret i32* %t5
4145 }
4146</pre>
4147
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4148<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4149 <tt>getelementptr</tt> is undefined if the base pointer is not an
4150 <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]4151 that would be formed by successive addition of the offsets implied by the
4152 indices to the base address with infinitely precise arithmetic are not an
4153 <i>in bounds</i> address of that allocated object.
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4154 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4155 that point into the object, plus the address one byte past the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4156
4157<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4158 the base address with silently-wrapping two's complement arithmetic, and
4159 the result value of the <tt>getelementptr</tt> may be outside the object
4160 pointed to by the base pointer. The result value may not necessarily be
4161 used to access memory though, even if it happens to point into allocated
4162 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4163 section for more information.</p>
4164
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4165<p>The getelementptr instruction is often confusing. For some more insight into
4166 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4167
4168<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4169<pre>
4170 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4171 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4172 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4173 %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]4174 <i>; yields i8*:eptr</i>
4175 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4176 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4177 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4178</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4179
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4180</div>
4181
4182<!-- ======================================================================= -->
4183<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4184</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4185
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4186<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4187
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4188<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4189 which all take a single operand and a type. They perform various bit
4190 conversions on the operand.</p>
4191
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4192</div>
4193
4194<!-- _______________________________________________________________________ -->
4195<div class="doc_subsubsection">
4196 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4197</div>
4198<div class="doc_text">
4199
4200<h5>Syntax:</h5>
4201<pre>
4202 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4203</pre>
4204
4205<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4206<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4207 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4208
4209<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4210<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4211 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4212 size and type of the result, which must be
4213 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4214 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4215 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4216
4217<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4218<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4219 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4220 source size must be larger than the destination size, <tt>trunc</tt> cannot
4221 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4222
4223<h5>Example:</h5>
4224<pre>
4225 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4226 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4227 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
4228</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4229
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4230</div>
4231
4232<!-- _______________________________________________________________________ -->
4233<div class="doc_subsubsection">
4234 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4235</div>
4236<div class="doc_text">
4237
4238<h5>Syntax:</h5>
4239<pre>
4240 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4241</pre>
4242
4243<h5>Overview:</h5>
4244<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4245 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4246
4247
4248<h5>Arguments:</h5>
4249<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]4250 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4251 also be of <a href="#t_integer">integer</a> type. The bit size of the
4252 <tt>value</tt> must be smaller than the bit size of the destination type,
4253 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4254
4255<h5>Semantics:</h5>
4256<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]4257 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4258
4259<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4260
4261<h5>Example:</h5>
4262<pre>
4263 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4264 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4265</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4266
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4267</div>
4268
4269<!-- _______________________________________________________________________ -->
4270<div class="doc_subsubsection">
4271 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4272</div>
4273<div class="doc_text">
4274
4275<h5>Syntax:</h5>
4276<pre>
4277 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4278</pre>
4279
4280<h5>Overview:</h5>
4281<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4282
4283<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4284<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4285 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4286 also be of <a href="#t_integer">integer</a> type. The bit size of the
4287 <tt>value</tt> must be smaller than the bit size of the destination type,
4288 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4289
4290<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4291<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4292 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4293 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4294
4295<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4296
4297<h5>Example:</h5>
4298<pre>
4299 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4300 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4301</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4302
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4303</div>
4304
4305<!-- _______________________________________________________________________ -->
4306<div class="doc_subsubsection">
4307 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4308</div>
4309
4310<div class="doc_text">
4311
4312<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4313<pre>
4314 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4315</pre>
4316
4317<h5>Overview:</h5>
4318<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4319 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4320
4321<h5>Arguments:</h5>
4322<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4323 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4324 to cast it to. The size of <tt>value</tt> must be larger than the size of
4325 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4326 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4327
4328<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4329<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4330 <a href="#t_floating">floating point</a> type to a smaller
4331 <a href="#t_floating">floating point</a> type. If the value cannot fit
4332 within the destination type, <tt>ty2</tt>, then the results are
4333 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4334
4335<h5>Example:</h5>
4336<pre>
4337 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4338 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4339</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4340
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4341</div>
4342
4343<!-- _______________________________________________________________________ -->
4344<div class="doc_subsubsection">
4345 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4346</div>
4347<div class="doc_text">
4348
4349<h5>Syntax:</h5>
4350<pre>
4351 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4352</pre>
4353
4354<h5>Overview:</h5>
4355<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]4356 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4357
4358<h5>Arguments:</h5>
4359<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4360 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4361 a <a href="#t_floating">floating point</a> type to cast it to. The source
4362 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4363
4364<h5>Semantics:</h5>
4365<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4366 <a href="#t_floating">floating point</a> type to a larger
4367 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4368 used to make a <i>no-op cast</i> because it always changes bits. Use
4369 <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]4370
4371<h5>Example:</h5>
4372<pre>
4373 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4374 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4375</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4376
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4377</div>
4378
4379<!-- _______________________________________________________________________ -->
4380<div class="doc_subsubsection">
4381 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4382</div>
4383<div class="doc_text">
4384
4385<h5>Syntax:</h5>
4386<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4387 &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]4388</pre>
4389
4390<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4391<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4392 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4393
4394<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4395<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4396 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4397 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4398 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4399 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4400
4401<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4402<p>The '<tt>fptoui</tt>' instruction converts its
4403 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4404 towards zero) unsigned integer value. If the value cannot fit
4405 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4406
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4407<h5>Example:</h5>
4408<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4409 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4410 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4411 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4412</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4413
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4414</div>
4415
4416<!-- _______________________________________________________________________ -->
4417<div class="doc_subsubsection">
4418 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4419</div>
4420<div class="doc_text">
4421
4422<h5>Syntax:</h5>
4423<pre>
4424 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4425</pre>
4426
4427<h5>Overview:</h5>
4428<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4429 <a href="#t_floating">floating point</a> <tt>value</tt> to
4430 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4431
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4432<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4433<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4434 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4435 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4436 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4437 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4438
4439<h5>Semantics:</h5>
4440<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4441 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4442 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4443 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4444
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4445<h5>Example:</h5>
4446<pre>
4447 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4448 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4449 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4450</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4451
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4452</div>
4453
4454<!-- _______________________________________________________________________ -->
4455<div class="doc_subsubsection">
4456 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4457</div>
4458<div class="doc_text">
4459
4460<h5>Syntax:</h5>
4461<pre>
4462 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4463</pre>
4464
4465<h5>Overview:</h5>
4466<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4467 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4468
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4469<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4470<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]4471 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4472 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4473 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4474 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4475
4476<h5>Semantics:</h5>
4477<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4478 integer quantity and converts it to the corresponding floating point
4479 value. If the value cannot fit in the floating point value, the results are
4480 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4481
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4482<h5>Example:</h5>
4483<pre>
4484 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4485 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4486</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4487
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4488</div>
4489
4490<!-- _______________________________________________________________________ -->
4491<div class="doc_subsubsection">
4492 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4493</div>
4494<div class="doc_text">
4495
4496<h5>Syntax:</h5>
4497<pre>
4498 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4499</pre>
4500
4501<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4502<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4503 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4504
4505<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4506<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]4507 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4508 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4509 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4510 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4511
4512<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4513<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4514 quantity and converts it to the corresponding floating point value. If the
4515 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4516
4517<h5>Example:</h5>
4518<pre>
4519 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4520 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4521</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4522
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4523</div>
4524
4525<!-- _______________________________________________________________________ -->
4526<div class="doc_subsubsection">
4527 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4528</div>
4529<div class="doc_text">
4530
4531<h5>Syntax:</h5>
4532<pre>
4533 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4534</pre>
4535
4536<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4537<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4538 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4539
4540<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4541<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4542 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4543 <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]4544
4545<h5>Semantics:</h5>
4546<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4547 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4548 truncating or zero extending that value to the size of the integer type. If
4549 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4550 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4551 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4552 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4553
4554<h5>Example:</h5>
4555<pre>
4556 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4557 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4558</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4559
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4560</div>
4561
4562<!-- _______________________________________________________________________ -->
4563<div class="doc_subsubsection">
4564 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4565</div>
4566<div class="doc_text">
4567
4568<h5>Syntax:</h5>
4569<pre>
4570 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4571</pre>
4572
4573<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4574<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4575 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4576
4577<h5>Arguments:</h5>
4578<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4579 value to cast, and a type to cast it to, which must be a
4580 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4581
4582<h5>Semantics:</h5>
4583<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4584 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4585 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4586 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4587 than the size of a pointer then a zero extension is done. If they are the
4588 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4589
4590<h5>Example:</h5>
4591<pre>
4592 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4593 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4594 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4595</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4596
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4597</div>
4598
4599<!-- _______________________________________________________________________ -->
4600<div class="doc_subsubsection">
4601 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4602</div>
4603<div class="doc_text">
4604
4605<h5>Syntax:</h5>
4606<pre>
4607 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4608</pre>
4609
4610<h5>Overview:</h5>
4611<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4612 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4613
4614<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4615<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4616 non-aggregate first class value, and a type to cast it to, which must also be
4617 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4618 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4619 identical. If the source type is a pointer, the destination type must also be
4620 a pointer. This instruction supports bitwise conversion of vectors to
4621 integers and to vectors of other types (as long as they have the same
4622 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4623
4624<h5>Semantics:</h5>
4625<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4626 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4627 this conversion. The conversion is done as if the <tt>value</tt> had been
4628 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4629 be converted to other pointer types with this instruction. To convert
4630 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4631 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4632
4633<h5>Example:</h5>
4634<pre>
4635 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4636 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4637 %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]4638</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4640</div>
4641
4642<!-- ======================================================================= -->
4643<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4644
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4645<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4646
4647<p>The instructions in this category are the "miscellaneous" instructions, which
4648 defy better classification.</p>
4649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4650</div>
4651
4652<!-- _______________________________________________________________________ -->
4653<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4654</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4655
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4656<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4657
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4658<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4659<pre>
4660 &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]4661</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4663<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4664<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4665 boolean values based on comparison of its two integer, integer vector, or
4666 pointer operands.</p>
4667
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4668<h5>Arguments:</h5>
4669<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4670 the condition code indicating the kind of comparison to perform. It is not a
4671 value, just a keyword. The possible condition code are:</p>
4672
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4673<ol>
4674 <li><tt>eq</tt>: equal</li>
4675 <li><tt>ne</tt>: not equal </li>
4676 <li><tt>ugt</tt>: unsigned greater than</li>
4677 <li><tt>uge</tt>: unsigned greater or equal</li>
4678 <li><tt>ult</tt>: unsigned less than</li>
4679 <li><tt>ule</tt>: unsigned less or equal</li>
4680 <li><tt>sgt</tt>: signed greater than</li>
4681 <li><tt>sge</tt>: signed greater or equal</li>
4682 <li><tt>slt</tt>: signed less than</li>
4683 <li><tt>sle</tt>: signed less or equal</li>
4684</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4685
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4686<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4687 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4688 typed. They must also be identical types.</p>
4689
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4690<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4691<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4692 condition code given as <tt>cond</tt>. The comparison performed always yields
4693 either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt>
4694 result, as follows:</p>
4695
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4696<ol>
4697 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4698 <tt>false</tt> otherwise. No sign interpretation is necessary or
4699 performed.</li>
4700
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4701 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4702 <tt>false</tt> otherwise. No sign interpretation is necessary or
4703 performed.</li>
4704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4705 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4706 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4707
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4708 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4709 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4710 to <tt>op2</tt>.</li>
4711
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4712 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4713 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4714
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4715 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4716 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4717
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4718 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4719 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4720
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4721 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4722 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4723 to <tt>op2</tt>.</li>
4724
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4725 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4726 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4727
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4728 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4729 <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]4730</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4731
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4732<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4733 values are compared as if they were integers.</p>
4734
4735<p>If the operands are integer vectors, then they are compared element by
4736 element. The result is an <tt>i1</tt> vector with the same number of elements
4737 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4738
4739<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4740<pre>
4741 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4742 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4743 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4744 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4745 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4746 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4747</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4748
4749<p>Note that the code generator does not yet support vector types with
4750 the <tt>icmp</tt> instruction.</p>
4751
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4752</div>
4753
4754<!-- _______________________________________________________________________ -->
4755<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4756</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4757
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4758<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4759
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4760<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4761<pre>
4762 &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]4763</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4764
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4765<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4766<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4767 values based on comparison of its operands.</p>
4768
4769<p>If the operands are floating point scalars, then the result type is a boolean
4770(<a href="#t_primitive"><tt>i1</tt></a>).</p>
4771
4772<p>If the operands are floating point vectors, then the result type is a vector
4773 of boolean with the same number of elements as the operands being
4774 compared.</p>
4775
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4776<h5>Arguments:</h5>
4777<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4778 the condition code indicating the kind of comparison to perform. It is not a
4779 value, just a keyword. The possible condition code are:</p>
4780
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4781<ol>
4782 <li><tt>false</tt>: no comparison, always returns false</li>
4783 <li><tt>oeq</tt>: ordered and equal</li>
4784 <li><tt>ogt</tt>: ordered and greater than </li>
4785 <li><tt>oge</tt>: ordered and greater than or equal</li>
4786 <li><tt>olt</tt>: ordered and less than </li>
4787 <li><tt>ole</tt>: ordered and less than or equal</li>
4788 <li><tt>one</tt>: ordered and not equal</li>
4789 <li><tt>ord</tt>: ordered (no nans)</li>
4790 <li><tt>ueq</tt>: unordered or equal</li>
4791 <li><tt>ugt</tt>: unordered or greater than </li>
4792 <li><tt>uge</tt>: unordered or greater than or equal</li>
4793 <li><tt>ult</tt>: unordered or less than </li>
4794 <li><tt>ule</tt>: unordered or less than or equal</li>
4795 <li><tt>une</tt>: unordered or not equal</li>
4796 <li><tt>uno</tt>: unordered (either nans)</li>
4797 <li><tt>true</tt>: no comparison, always returns true</li>
4798</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4799
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4800<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4801 <i>unordered</i> means that either operand may be a QNAN.</p>
4802
4803<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4804 a <a href="#t_floating">floating point</a> type or
4805 a <a href="#t_vector">vector</a> of floating point type. They must have
4806 identical types.</p>
4807
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4808<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4809<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4810 according to the condition code given as <tt>cond</tt>. If the operands are
4811 vectors, then the vectors are compared element by element. Each comparison
4812 performed always yields an <a href="#t_primitive">i1</a> result, as
4813 follows:</p>
4814
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4815<ol>
4816 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4817
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4818 <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]4819 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4820
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4821 <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]4822 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4823
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4824 <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]4825 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4826
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4827 <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]4828 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4829
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4830 <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]4831 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4832
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4833 <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]4834 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4835
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4836 <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]4837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4838 <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]4839 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4840
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4841 <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]4842 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4843
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4844 <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]4845 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4846
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4847 <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]4848 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4849
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4850 <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]4851 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4852
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4853 <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]4854 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4855
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4856 <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]4857
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4858 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4859</ol>
4860
4861<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4862<pre>
4863 &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]4864 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4865 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4866 &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]4867</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4868
4869<p>Note that the code generator does not yet support vector types with
4870 the <tt>fcmp</tt> instruction.</p>
4871
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4872</div>
4873
4874<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4875<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4876 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4877</div>
4878
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4879<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4880
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4881<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4882<pre>
4883 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4884</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4885
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4886<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4887<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4888 SSA graph representing the function.</p>
4889
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4890<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4891<p>The type of the incoming values is specified with the first type field. After
4892 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4893 one pair for each predecessor basic block of the current block. Only values
4894 of <a href="#t_firstclass">first class</a> type may be used as the value
4895 arguments to the PHI node. Only labels may be used as the label
4896 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4897
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4898<p>There must be no non-phi instructions between the start of a basic block and
4899 the PHI instructions: i.e. PHI instructions must be first in a basic
4900 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4901
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4902<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4903 occur on the edge from the corresponding predecessor block to the current
4904 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4905 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4906
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4907<h5>Semantics:</h5>
4908<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4909 specified by the pair corresponding to the predecessor basic block that
4910 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4911
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4912<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4913<pre>
4914Loop: ; Infinite loop that counts from 0 on up...
4915 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4916 %nextindvar = add i32 %indvar, 1
4917 br label %Loop
4918</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4919
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4920</div>
4921
4922<!-- _______________________________________________________________________ -->
4923<div class="doc_subsubsection">
4924 <a name="i_select">'<tt>select</tt>' Instruction</a>
4925</div>
4926
4927<div class="doc_text">
4928
4929<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4930<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4931 &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>
4932
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4933 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4934</pre>
4935
4936<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4937<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4938 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4939
4940
4941<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4942<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4943 values indicating the condition, and two values of the
4944 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4945 vectors and the condition is a scalar, then entire vectors are selected, not
4946 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4947
4948<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4949<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4950 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4951
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4952<p>If the condition is a vector of i1, then the value arguments must be vectors
4953 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4954
4955<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4956<pre>
4957 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4958</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4959
4960<p>Note that the code generator does not yet support conditions
4961 with vector type.</p>
4962
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4963</div>
4964
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4965<!-- _______________________________________________________________________ -->
4966<div class="doc_subsubsection">
4967 <a name="i_call">'<tt>call</tt>' Instruction</a>
4968</div>
4969
4970<div class="doc_text">
4971
4972<h5>Syntax:</h5>
4973<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4974 &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]4975</pre>
4976
4977<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4978<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4979
4980<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4981<p>This instruction requires several arguments:</p>
4982
4983<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4984 <li>The optional "tail" marker indicates whether the callee function accesses
4985 any allocas or varargs in the caller. If the "tail" marker is present,
4986 the function call is eligible for tail call optimization. Note that calls
4987 may be marked "tail" even if they do not occur before
4988 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4989
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4990 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4991 convention</a> the call should use. If none is specified, the call
4992 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4993
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4994 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4995 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4996 '<tt>inreg</tt>' attributes are valid here.</li>
4997
4998 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
4999 type of the return value. Functions that return no value are marked
5000 <tt><a href="#t_void">void</a></tt>.</li>
5001
5002 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5003 being invoked. The argument types must match the types implied by this
5004 signature. This type can be omitted if the function is not varargs and if
5005 the function type does not return a pointer to a function.</li>
5006
5007 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5008 be invoked. In most cases, this is a direct function invocation, but
5009 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5010 to function value.</li>
5011
5012 <li>'<tt>function args</tt>': argument list whose types match the function
5013 signature argument types. All arguments must be of
5014 <a href="#t_firstclass">first class</a> type. If the function signature
5015 indicates the function accepts a variable number of arguments, the extra
5016 arguments can be specified.</li>
5017
5018 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5019 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5020 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5021</ol>
5022
5023<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5024<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5025 a specified function, with its incoming arguments bound to the specified
5026 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5027 function, control flow continues with the instruction after the function
5028 call, and the return value of the function is bound to the result
5029 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5030
5031<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5032<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5033 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5034 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5035 %X = tail call i32 @foo() <i>; yields i32</i>
5036 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5037 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5038
5039 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5040 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5041 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5042 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5043 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5044 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5045</pre>
5046
5047</div>
5048
5049<!-- _______________________________________________________________________ -->
5050<div class="doc_subsubsection">
5051 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5052</div>
5053
5054<div class="doc_text">
5055
5056<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5057<pre>
5058 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5059</pre>
5060
5061<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5062<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5063 the "variable argument" area of a function call. It is used to implement the
5064 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5065
5066<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5067<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5068 argument. It returns a value of the specified argument type and increments
5069 the <tt>va_list</tt> to point to the next argument. The actual type
5070 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5071
5072<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5073<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5074 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5075 to the next argument. For more information, see the variable argument
5076 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5077
5078<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]5079 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5080 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5081
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5082<p><tt>va_arg</tt> is an LLVM instruction instead of
5083 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5084 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5085
5086<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5087<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5088
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5089<p>Note that the code generator does not yet fully support va_arg on many
5090 targets. Also, it does not currently support va_arg with aggregate types on
5091 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5092
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5093</div>
5094
5095<!-- *********************************************************************** -->
5096<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5097<!-- *********************************************************************** -->
5098
5099<div class="doc_text">
5100
5101<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5102 well known names and semantics and are required to follow certain
5103 restrictions. Overall, these intrinsics represent an extension mechanism for
5104 the LLVM language that does not require changing all of the transformations
5105 in LLVM when adding to the language (or the bitcode reader/writer, the
5106 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5107
5108<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5109 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5110 begin with this prefix. Intrinsic functions must always be external
5111 functions: you cannot define the body of intrinsic functions. Intrinsic
5112 functions may only be used in call or invoke instructions: it is illegal to
5113 take the address of an intrinsic function. Additionally, because intrinsic
5114 functions are part of the LLVM language, it is required if any are added that
5115 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5116
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5117<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5118 family of functions that perform the same operation but on different data
5119 types. Because LLVM can represent over 8 million different integer types,
5120 overloading is used commonly to allow an intrinsic function to operate on any
5121 integer type. One or more of the argument types or the result type can be
5122 overloaded to accept any integer type. Argument types may also be defined as
5123 exactly matching a previous argument's type or the result type. This allows
5124 an intrinsic function which accepts multiple arguments, but needs all of them
5125 to be of the same type, to only be overloaded with respect to a single
5126 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5127
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5128<p>Overloaded intrinsics will have the names of its overloaded argument types
5129 encoded into its function name, each preceded by a period. Only those types
5130 which are overloaded result in a name suffix. Arguments whose type is matched
5131 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5132 can take an integer of any width and returns an integer of exactly the same
5133 integer width. This leads to a family of functions such as
5134 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5135 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5136 suffix is required. Because the argument's type is matched against the return
5137 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5138
5139<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5140 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5141
5142</div>
5143
5144<!-- ======================================================================= -->
5145<div class="doc_subsection">
5146 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5147</div>
5148
5149<div class="doc_text">
5150
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5151<p>Variable argument support is defined in LLVM with
5152 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5153 intrinsic functions. These functions are related to the similarly named
5154 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5155
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5156<p>All of these functions operate on arguments that use a target-specific value
5157 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5158 not define what this type is, so all transformations should be prepared to
5159 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5160
5161<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]5162 instruction and the variable argument handling intrinsic functions are
5163 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5164
5165<div class="doc_code">
5166<pre>
5167define i32 @test(i32 %X, ...) {
5168 ; Initialize variable argument processing
5169 %ap = alloca i8*
5170 %ap2 = bitcast i8** %ap to i8*
5171 call void @llvm.va_start(i8* %ap2)
5172
5173 ; Read a single integer argument
5174 %tmp = va_arg i8** %ap, i32
5175
5176 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5177 %aq = alloca i8*
5178 %aq2 = bitcast i8** %aq to i8*
5179 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5180 call void @llvm.va_end(i8* %aq2)
5181
5182 ; Stop processing of arguments.
5183 call void @llvm.va_end(i8* %ap2)
5184 ret i32 %tmp
5185}
5186
5187declare void @llvm.va_start(i8*)
5188declare void @llvm.va_copy(i8*, i8*)
5189declare void @llvm.va_end(i8*)
5190</pre>
5191</div>
5192
5193</div>
5194
5195<!-- _______________________________________________________________________ -->
5196<div class="doc_subsubsection">
5197 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5198</div>
5199
5200
5201<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5202
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5203<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5204<pre>
5205 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5206</pre>
5207
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5208<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5209<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5210 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]5211
5212<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5213<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]5214
5215<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5216<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]5217 macro available in C. In a target-dependent way, it initializes
5218 the <tt>va_list</tt> element to which the argument points, so that the next
5219 call to <tt>va_arg</tt> will produce the first variable argument passed to
5220 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5221 need to know the last argument of the function as the compiler can figure
5222 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5223
5224</div>
5225
5226<!-- _______________________________________________________________________ -->
5227<div class="doc_subsubsection">
5228 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5229</div>
5230
5231<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5232
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5233<h5>Syntax:</h5>
5234<pre>
5235 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5236</pre>
5237
5238<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5239<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5240 which has been initialized previously
5241 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5242 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5243
5244<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5245<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5246
5247<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5248<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]5249 macro available in C. In a target-dependent way, it destroys
5250 the <tt>va_list</tt> element to which the argument points. Calls
5251 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5252 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5253 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5254
5255</div>
5256
5257<!-- _______________________________________________________________________ -->
5258<div class="doc_subsubsection">
5259 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5260</div>
5261
5262<div class="doc_text">
5263
5264<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5265<pre>
5266 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5267</pre>
5268
5269<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5270<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5271 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5272
5273<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5274<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]5275 The second argument is a pointer to a <tt>va_list</tt> element to copy
5276 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5277
5278<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5279<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]5280 macro available in C. In a target-dependent way, it copies the
5281 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5282 element. This intrinsic is necessary because
5283 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5284 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5285
5286</div>
5287
5288<!-- ======================================================================= -->
5289<div class="doc_subsection">
5290 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5291</div>
5292
5293<div class="doc_text">
5294
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5295<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5296Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5297intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5298roots on the stack</a>, as well as garbage collector implementations that
5299require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5300barriers. Front-ends for type-safe garbage collected languages should generate
5301these intrinsics to make use of the LLVM garbage collectors. For more details,
5302see <a href="GarbageCollection.html">Accurate Garbage Collection with
5303LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5304
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5305<p>The garbage collection intrinsics only operate on objects in the generic
5306 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5307
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5308</div>
5309
5310<!-- _______________________________________________________________________ -->
5311<div class="doc_subsubsection">
5312 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5313</div>
5314
5315<div class="doc_text">
5316
5317<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5318<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5319 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5320</pre>
5321
5322<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5323<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]5324 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5325
5326<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5327<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5328 root pointer. The second pointer (which must be either a constant or a
5329 global value address) contains the meta-data to be associated with the
5330 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5331
5332<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5333<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]5334 location. At compile-time, the code generator generates information to allow
5335 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5336 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5337 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5338
5339</div>
5340
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5341<!-- _______________________________________________________________________ -->
5342<div class="doc_subsubsection">
5343 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5344</div>
5345
5346<div class="doc_text">
5347
5348<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5349<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5350 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5351</pre>
5352
5353<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5354<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5355 locations, allowing garbage collector implementations that require read
5356 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5357
5358<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5359<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]5360 allocated from the garbage collector. The first object is a pointer to the
5361 start of the referenced object, if needed by the language runtime (otherwise
5362 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5363
5364<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5365<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5366 instruction, but may be replaced with substantially more complex code by the
5367 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5368 may only be used in a function which <a href="#gc">specifies a GC
5369 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5370
5371</div>
5372
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5373<!-- _______________________________________________________________________ -->
5374<div class="doc_subsubsection">
5375 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5376</div>
5377
5378<div class="doc_text">
5379
5380<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5381<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5382 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5383</pre>
5384
5385<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5386<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5387 locations, allowing garbage collector implementations that require write
5388 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5389
5390<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5391<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]5392 object to store it to, and the third is the address of the field of Obj to
5393 store to. If the runtime does not require a pointer to the object, Obj may
5394 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5395
5396<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5397<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5398 instruction, but may be replaced with substantially more complex code by the
5399 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5400 may only be used in a function which <a href="#gc">specifies a GC
5401 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5402
5403</div>
5404
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5405<!-- ======================================================================= -->
5406<div class="doc_subsection">
5407 <a name="int_codegen">Code Generator Intrinsics</a>
5408</div>
5409
5410<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5411
5412<p>These intrinsics are provided by LLVM to expose special features that may
5413 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5414
5415</div>
5416
5417<!-- _______________________________________________________________________ -->
5418<div class="doc_subsubsection">
5419 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5420</div>
5421
5422<div class="doc_text">
5423
5424<h5>Syntax:</h5>
5425<pre>
5426 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5427</pre>
5428
5429<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5430<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5431 target-specific value indicating the return address of the current function
5432 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5433
5434<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5435<p>The argument to this intrinsic indicates which function to return the address
5436 for. Zero indicates the calling function, one indicates its caller, etc.
5437 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5438
5439<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5440<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5441 indicating the return address of the specified call frame, or zero if it
5442 cannot be identified. The value returned by this intrinsic is likely to be
5443 incorrect or 0 for arguments other than zero, so it should only be used for
5444 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5445
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5446<p>Note that calling this intrinsic does not prevent function inlining or other
5447 aggressive transformations, so the value returned may not be that of the
5448 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5449
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5450</div>
5451
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5452<!-- _______________________________________________________________________ -->
5453<div class="doc_subsubsection">
5454 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5455</div>
5456
5457<div class="doc_text">
5458
5459<h5>Syntax:</h5>
5460<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5461 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5462</pre>
5463
5464<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5465<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5466 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5467
5468<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5469<p>The argument to this intrinsic indicates which function to return the frame
5470 pointer for. Zero indicates the calling function, one indicates its caller,
5471 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5472
5473<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5474<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5475 indicating the frame address of the specified call frame, or zero if it
5476 cannot be identified. The value returned by this intrinsic is likely to be
5477 incorrect or 0 for arguments other than zero, so it should only be used for
5478 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5479
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5480<p>Note that calling this intrinsic does not prevent function inlining or other
5481 aggressive transformations, so the value returned may not be that of the
5482 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5483
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5484</div>
5485
5486<!-- _______________________________________________________________________ -->
5487<div class="doc_subsubsection">
5488 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5489</div>
5490
5491<div class="doc_text">
5492
5493<h5>Syntax:</h5>
5494<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5495 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5496</pre>
5497
5498<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5499<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5500 of the function stack, for use
5501 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5502 useful for implementing language features like scoped automatic variable
5503 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5504
5505<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5506<p>This intrinsic returns a opaque pointer value that can be passed
5507 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5508 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5509 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5510 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5511 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5512 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5513
5514</div>
5515
5516<!-- _______________________________________________________________________ -->
5517<div class="doc_subsubsection">
5518 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5519</div>
5520
5521<div class="doc_text">
5522
5523<h5>Syntax:</h5>
5524<pre>
5525 declare void @llvm.stackrestore(i8 * %ptr)
5526</pre>
5527
5528<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5529<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5530 the function stack to the state it was in when the
5531 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5532 executed. This is useful for implementing language features like scoped
5533 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5534
5535<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5536<p>See the description
5537 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5538
5539</div>
5540
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5541<!-- _______________________________________________________________________ -->
5542<div class="doc_subsubsection">
5543 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5544</div>
5545
5546<div class="doc_text">
5547
5548<h5>Syntax:</h5>
5549<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5550 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]5551</pre>
5552
5553<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5554<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5555 insert a prefetch instruction if supported; otherwise, it is a noop.
5556 Prefetches have no effect on the behavior of the program but can change its
5557 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5558
5559<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5560<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5561 specifier determining if the fetch should be for a read (0) or write (1),
5562 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5563 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5564 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5565
5566<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5567<p>This intrinsic does not modify the behavior of the program. In particular,
5568 prefetches cannot trap and do not produce a value. On targets that support
5569 this intrinsic, the prefetch can provide hints to the processor cache for
5570 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5571
5572</div>
5573
5574<!-- _______________________________________________________________________ -->
5575<div class="doc_subsubsection">
5576 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5577</div>
5578
5579<div class="doc_text">
5580
5581<h5>Syntax:</h5>
5582<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5583 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5584</pre>
5585
5586<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5587<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5588 Counter (PC) in a region of code to simulators and other tools. The method
5589 is target specific, but it is expected that the marker will use exported
5590 symbols to transmit the PC of the marker. The marker makes no guarantees
5591 that it will remain with any specific instruction after optimizations. It is
5592 possible that the presence of a marker will inhibit optimizations. The
5593 intended use is to be inserted after optimizations to allow correlations of
5594 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5595
5596<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5597<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5598
5599<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5600<p>This intrinsic does not modify the behavior of the program. Backends that do
5601 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5602
5603</div>
5604
5605<!-- _______________________________________________________________________ -->
5606<div class="doc_subsubsection">
5607 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5608</div>
5609
5610<div class="doc_text">
5611
5612<h5>Syntax:</h5>
5613<pre>
5614 declare i64 @llvm.readcyclecounter( )
5615</pre>
5616
5617<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5618<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5619 counter register (or similar low latency, high accuracy clocks) on those
5620 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5621 should map to RPCC. As the backing counters overflow quickly (on the order
5622 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5623
5624<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5625<p>When directly supported, reading the cycle counter should not modify any
5626 memory. Implementations are allowed to either return a application specific
5627 value or a system wide value. On backends without support, this is lowered
5628 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5629
5630</div>
5631
5632<!-- ======================================================================= -->
5633<div class="doc_subsection">
5634 <a name="int_libc">Standard C Library Intrinsics</a>
5635</div>
5636
5637<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5638
5639<p>LLVM provides intrinsics for a few important standard C library functions.
5640 These intrinsics allow source-language front-ends to pass information about
5641 the alignment of the pointer arguments to the code generator, providing
5642 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5643
5644</div>
5645
5646<!-- _______________________________________________________________________ -->
5647<div class="doc_subsubsection">
5648 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5649</div>
5650
5651<div class="doc_text">
5652
5653<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5654<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5655 integer bit width. Not all targets support all bit widths however.</p>
5656
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5657<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5658 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5659 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5660 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5661 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5662 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5663 i32 &lt;len&gt;, i32 &lt;align&gt;)
5664 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5665 i64 &lt;len&gt;, i32 &lt;align&gt;)
5666</pre>
5667
5668<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5669<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5670 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5671
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5672<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5673 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5674
5675<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5676<p>The first argument is a pointer to the destination, the second is a pointer
5677 to the source. The third argument is an integer argument specifying the
5678 number of bytes to copy, and the fourth argument is the alignment of the
5679 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5680
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5681<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5682 then the caller guarantees that both the source and destination pointers are
5683 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5684
5685<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5686<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5687 source location to the destination location, which are not allowed to
5688 overlap. It copies "len" bytes of memory over. If the argument is known to
5689 be aligned to some boundary, this can be specified as the fourth argument,
5690 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5691
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5692</div>
5693
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5694<!-- _______________________________________________________________________ -->
5695<div class="doc_subsubsection">
5696 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5697</div>
5698
5699<div class="doc_text">
5700
5701<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5702<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]5703 width. Not all targets support all bit widths however.</p>
5704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5705<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5706 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5707 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5708 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5709 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5710 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5711 i32 &lt;len&gt;, i32 &lt;align&gt;)
5712 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5713 i64 &lt;len&gt;, i32 &lt;align&gt;)
5714</pre>
5715
5716<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5717<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5718 source location to the destination location. It is similar to the
5719 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5720 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5721
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5722<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5723 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5724
5725<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5726<p>The first argument is a pointer to the destination, the second is a pointer
5727 to the source. The third argument is an integer argument specifying the
5728 number of bytes to copy, and the fourth argument is the alignment of the
5729 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5730
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5731<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5732 then the caller guarantees that the source and destination pointers are
5733 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5734
5735<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5736<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5737 source location to the destination location, which may overlap. It copies
5738 "len" bytes of memory over. If the argument is known to be aligned to some
5739 boundary, this can be specified as the fourth argument, otherwise it should
5740 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5741
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5742</div>
5743
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5744<!-- _______________________________________________________________________ -->
5745<div class="doc_subsubsection">
5746 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5747</div>
5748
5749<div class="doc_text">
5750
5751<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5752<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]5753 width. Not all targets support all bit widths however.</p>
5754
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5755<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5756 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5757 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5758 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5759 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5760 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5761 i32 &lt;len&gt;, i32 &lt;align&gt;)
5762 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5763 i64 &lt;len&gt;, i32 &lt;align&gt;)
5764</pre>
5765
5766<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5767<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5768 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5769
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5770<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5771 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5772
5773<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5774<p>The first argument is a pointer to the destination to fill, the second is the
5775 byte value to fill it with, the third argument is an integer argument
5776 specifying the number of bytes to fill, and the fourth argument is the known
5777 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5778
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5779<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5780 then the caller guarantees that the destination pointer is aligned to that
5781 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5782
5783<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5784<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5785 at the destination location. If the argument is known to be aligned to some
5786 boundary, this can be specified as the fourth argument, otherwise it should
5787 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5788
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5789</div>
5790
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5791<!-- _______________________________________________________________________ -->
5792<div class="doc_subsubsection">
5793 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5794</div>
5795
5796<div class="doc_text">
5797
5798<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5799<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5800 floating point or vector of floating point type. Not all targets support all
5801 types however.</p>
5802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5803<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5804 declare float @llvm.sqrt.f32(float %Val)
5805 declare double @llvm.sqrt.f64(double %Val)
5806 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5807 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5808 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5809</pre>
5810
5811<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5812<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5813 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5814 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5815 behavior for negative numbers other than -0.0 (which allows for better
5816 optimization, because there is no need to worry about errno being
5817 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]5818
5819<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5820<p>The argument and return value are floating point numbers of the same
5821 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5822
5823<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5824<p>This function returns the sqrt of the specified operand if it is a
5825 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5826
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5827</div>
5828
5829<!-- _______________________________________________________________________ -->
5830<div class="doc_subsubsection">
5831 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5832</div>
5833
5834<div class="doc_text">
5835
5836<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5837<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5838 floating point or vector of floating point type. Not all targets support all
5839 types however.</p>
5840
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5841<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5842 declare float @llvm.powi.f32(float %Val, i32 %power)
5843 declare double @llvm.powi.f64(double %Val, i32 %power)
5844 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5845 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5846 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5847</pre>
5848
5849<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5850<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5851 specified (positive or negative) power. The order of evaluation of
5852 multiplications is not defined. When a vector of floating point type is
5853 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5854
5855<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5856<p>The second argument is an integer power, and the first is a value to raise to
5857 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5858
5859<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5860<p>This function returns the first value raised to the second power with an
5861 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5862
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5863</div>
5864
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5865<!-- _______________________________________________________________________ -->
5866<div class="doc_subsubsection">
5867 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5868</div>
5869
5870<div class="doc_text">
5871
5872<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5873<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5874 floating point or vector of floating point type. Not all targets support all
5875 types however.</p>
5876
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5877<pre>
5878 declare float @llvm.sin.f32(float %Val)
5879 declare double @llvm.sin.f64(double %Val)
5880 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5881 declare fp128 @llvm.sin.f128(fp128 %Val)
5882 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5883</pre>
5884
5885<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5886<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5887
5888<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5889<p>The argument and return value are floating point numbers of the same
5890 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5891
5892<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5893<p>This function returns the sine of the specified operand, returning the same
5894 values as the libm <tt>sin</tt> functions would, and handles error conditions
5895 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5896
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5897</div>
5898
5899<!-- _______________________________________________________________________ -->
5900<div class="doc_subsubsection">
5901 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5902</div>
5903
5904<div class="doc_text">
5905
5906<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5907<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5908 floating point or vector of floating point type. Not all targets support all
5909 types however.</p>
5910
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5911<pre>
5912 declare float @llvm.cos.f32(float %Val)
5913 declare double @llvm.cos.f64(double %Val)
5914 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5915 declare fp128 @llvm.cos.f128(fp128 %Val)
5916 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5917</pre>
5918
5919<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5920<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5921
5922<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5923<p>The argument and return value are floating point numbers of the same
5924 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5925
5926<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5927<p>This function returns the cosine of the specified operand, returning the same
5928 values as the libm <tt>cos</tt> functions would, and handles error conditions
5929 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5930
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5931</div>
5932
5933<!-- _______________________________________________________________________ -->
5934<div class="doc_subsubsection">
5935 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5936</div>
5937
5938<div class="doc_text">
5939
5940<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5941<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5942 floating point or vector of floating point type. Not all targets support all
5943 types however.</p>
5944
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5945<pre>
5946 declare float @llvm.pow.f32(float %Val, float %Power)
5947 declare double @llvm.pow.f64(double %Val, double %Power)
5948 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5949 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5950 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5951</pre>
5952
5953<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5954<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5955 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5956
5957<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5958<p>The second argument is a floating point power, and the first is a value to
5959 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5960
5961<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5962<p>This function returns the first value raised to the second power, returning
5963 the same values as the libm <tt>pow</tt> functions would, and handles error
5964 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5965
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5966</div>
5967
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5968<!-- ======================================================================= -->
5969<div class="doc_subsection">
5970 <a name="int_manip">Bit Manipulation Intrinsics</a>
5971</div>
5972
5973<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5974
5975<p>LLVM provides intrinsics for a few important bit manipulation operations.
5976 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5977
5978</div>
5979
5980<!-- _______________________________________________________________________ -->
5981<div class="doc_subsubsection">
5982 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5983</div>
5984
5985<div class="doc_text">
5986
5987<h5>Syntax:</h5>
5988<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5989 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5990
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5991<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5992 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5993 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5994 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5995</pre>
5996
5997<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5998<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5999 values with an even number of bytes (positive multiple of 16 bits). These
6000 are useful for performing operations on data that is not in the target's
6001 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6002
6003<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6004<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6005 and low byte of the input i16 swapped. Similarly,
6006 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6007 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6008 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6009 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6010 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6011 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6012
6013</div>
6014
6015<!-- _______________________________________________________________________ -->
6016<div class="doc_subsubsection">
6017 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6018</div>
6019
6020<div class="doc_text">
6021
6022<h5>Syntax:</h5>
6023<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]6024 width. Not all targets support all bit widths however.</p>
6025
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6026<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6027 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6028 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6029 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6030 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6031 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6032</pre>
6033
6034<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6035<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6036 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6037
6038<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6039<p>The only argument is the value to be counted. The argument may be of any
6040 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6041
6042<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6043<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]6044
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6045</div>
6046
6047<!-- _______________________________________________________________________ -->
6048<div class="doc_subsubsection">
6049 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6050</div>
6051
6052<div class="doc_text">
6053
6054<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6055<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6056 integer bit width. Not all targets support all bit widths however.</p>
6057
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6058<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6059 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6060 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6061 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6062 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6063 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6064</pre>
6065
6066<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6067<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6068 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6069
6070<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6071<p>The only argument is the value to be counted. The argument may be of any
6072 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6073
6074<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6075<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6076 zeros in a variable. If the src == 0 then the result is the size in bits of
6077 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6078
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6079</div>
6080
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6081<!-- _______________________________________________________________________ -->
6082<div class="doc_subsubsection">
6083 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6084</div>
6085
6086<div class="doc_text">
6087
6088<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6089<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6090 integer bit width. Not all targets support all bit widths however.</p>
6091
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6092<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6093 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6094 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6095 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6096 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6097 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6098</pre>
6099
6100<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6101<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6102 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6103
6104<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6105<p>The only argument is the value to be counted. The argument may be of any
6106 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6107
6108<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6109<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6110 zeros in a variable. If the src == 0 then the result is the size in bits of
6111 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6112
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6113</div>
6114
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6115<!-- ======================================================================= -->
6116<div class="doc_subsection">
6117 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6118</div>
6119
6120<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6121
6122<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6123
6124</div>
6125
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6126<!-- _______________________________________________________________________ -->
6127<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6128 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6129</div>
6130
6131<div class="doc_text">
6132
6133<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6134<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]6135 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6136
6137<pre>
6138 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6139 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6140 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6141</pre>
6142
6143<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6144<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6145 a signed addition of the two arguments, and indicate whether an overflow
6146 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6147
6148<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6149<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]6150 be of integer types of any bit width, but they must have the same bit
6151 width. The second element of the result structure must be of
6152 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6153 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6154
6155<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6156<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6157 a signed addition of the two variables. They return a structure &mdash; the
6158 first element of which is the signed summation, and the second element of
6159 which is a bit specifying if the signed summation resulted in an
6160 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6161
6162<h5>Examples:</h5>
6163<pre>
6164 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6165 %sum = extractvalue {i32, i1} %res, 0
6166 %obit = extractvalue {i32, i1} %res, 1
6167 br i1 %obit, label %overflow, label %normal
6168</pre>
6169
6170</div>
6171
6172<!-- _______________________________________________________________________ -->
6173<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6174 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6175</div>
6176
6177<div class="doc_text">
6178
6179<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6180<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]6181 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6182
6183<pre>
6184 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6185 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6186 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6187</pre>
6188
6189<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6190<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6191 an unsigned addition of the two arguments, and indicate whether a carry
6192 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6193
6194<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6195<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]6196 be of integer types of any bit width, but they must have the same bit
6197 width. The second element of the result structure must be of
6198 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6199 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6200
6201<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6202<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6203 an unsigned addition of the two arguments. They return a structure &mdash;
6204 the first element of which is the sum, and the second element of which is a
6205 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6206
6207<h5>Examples:</h5>
6208<pre>
6209 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6210 %sum = extractvalue {i32, i1} %res, 0
6211 %obit = extractvalue {i32, i1} %res, 1
6212 br i1 %obit, label %carry, label %normal
6213</pre>
6214
6215</div>
6216
6217<!-- _______________________________________________________________________ -->
6218<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6219 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6220</div>
6221
6222<div class="doc_text">
6223
6224<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6225<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]6226 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6227
6228<pre>
6229 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6230 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6231 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6232</pre>
6233
6234<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6235<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6236 a signed subtraction of the two arguments, and indicate whether an overflow
6237 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6238
6239<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6240<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]6241 be of integer types of any bit width, but they must have the same bit
6242 width. The second element of the result structure must be of
6243 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6244 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6245
6246<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6247<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6248 a signed subtraction of the two arguments. They return a structure &mdash;
6249 the first element of which is the subtraction, and the second element of
6250 which is a bit specifying if the signed subtraction resulted in an
6251 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6252
6253<h5>Examples:</h5>
6254<pre>
6255 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6256 %sum = extractvalue {i32, i1} %res, 0
6257 %obit = extractvalue {i32, i1} %res, 1
6258 br i1 %obit, label %overflow, label %normal
6259</pre>
6260
6261</div>
6262
6263<!-- _______________________________________________________________________ -->
6264<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6265 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6266</div>
6267
6268<div class="doc_text">
6269
6270<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6271<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]6272 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6273
6274<pre>
6275 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6276 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6277 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6278</pre>
6279
6280<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6281<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6282 an unsigned subtraction of the two arguments, and indicate whether an
6283 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6284
6285<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6286<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]6287 be of integer types of any bit width, but they must have the same bit
6288 width. The second element of the result structure must be of
6289 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6290 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6291
6292<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6293<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6294 an unsigned subtraction of the two arguments. They return a structure &mdash;
6295 the first element of which is the subtraction, and the second element of
6296 which is a bit specifying if the unsigned subtraction resulted in an
6297 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6298
6299<h5>Examples:</h5>
6300<pre>
6301 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6302 %sum = extractvalue {i32, i1} %res, 0
6303 %obit = extractvalue {i32, i1} %res, 1
6304 br i1 %obit, label %overflow, label %normal
6305</pre>
6306
6307</div>
6308
6309<!-- _______________________________________________________________________ -->
6310<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6311 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6312</div>
6313
6314<div class="doc_text">
6315
6316<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6317<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]6318 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6319
6320<pre>
6321 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6322 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6323 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6324</pre>
6325
6326<h5>Overview:</h5>
6327
6328<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6329 a signed multiplication of the two arguments, and indicate whether an
6330 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6331
6332<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6333<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]6334 be of integer types of any bit width, but they must have the same bit
6335 width. The second element of the result structure must be of
6336 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6337 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6338
6339<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6340<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6341 a signed multiplication of the two arguments. They return a structure &mdash;
6342 the first element of which is the multiplication, and the second element of
6343 which is a bit specifying if the signed multiplication resulted in an
6344 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6345
6346<h5>Examples:</h5>
6347<pre>
6348 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6349 %sum = extractvalue {i32, i1} %res, 0
6350 %obit = extractvalue {i32, i1} %res, 1
6351 br i1 %obit, label %overflow, label %normal
6352</pre>
6353
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6354</div>
6355
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6356<!-- _______________________________________________________________________ -->
6357<div class="doc_subsubsection">
6358 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6359</div>
6360
6361<div class="doc_text">
6362
6363<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6364<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]6365 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6366
6367<pre>
6368 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6369 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6370 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6371</pre>
6372
6373<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6374<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6375 a unsigned multiplication of the two arguments, and indicate whether an
6376 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6377
6378<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6379<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]6380 be of integer types of any bit width, but they must have the same bit
6381 width. The second element of the result structure must be of
6382 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6383 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6384
6385<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6386<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6387 an unsigned multiplication of the two arguments. They return a structure
6388 &mdash; the first element of which is the multiplication, and the second
6389 element of which is a bit specifying if the unsigned multiplication resulted
6390 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6391
6392<h5>Examples:</h5>
6393<pre>
6394 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6395 %sum = extractvalue {i32, i1} %res, 0
6396 %obit = extractvalue {i32, i1} %res, 1
6397 br i1 %obit, label %overflow, label %normal
6398</pre>
6399
6400</div>
6401
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6402<!-- ======================================================================= -->
6403<div class="doc_subsection">
6404 <a name="int_debugger">Debugger Intrinsics</a>
6405</div>
6406
6407<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6408
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6409<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6410 prefix), are described in
6411 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6412 Level Debugging</a> document.</p>
6413
6414</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6415
6416<!-- ======================================================================= -->
6417<div class="doc_subsection">
6418 <a name="int_eh">Exception Handling Intrinsics</a>
6419</div>
6420
6421<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6422
6423<p>The LLVM exception handling intrinsics (which all start with
6424 <tt>llvm.eh.</tt> prefix), are described in
6425 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6426 Handling</a> document.</p>
6427
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6428</div>
6429
6430<!-- ======================================================================= -->
6431<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6432 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6433</div>
6434
6435<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6436
6437<p>This intrinsic makes it possible to excise one parameter, marked with
6438 the <tt>nest</tt> attribute, from a function. The result is a callable
6439 function pointer lacking the nest parameter - the caller does not need to
6440 provide a value for it. Instead, the value to use is stored in advance in a
6441 "trampoline", a block of memory usually allocated on the stack, which also
6442 contains code to splice the nest value into the argument list. This is used
6443 to implement the GCC nested function address extension.</p>
6444
6445<p>For example, if the function is
6446 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6447 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6448 follows:</p>
6449
6450<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6451<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6452 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6453 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6454 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6455 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6456</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6457</div>
6458
6459<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6460 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6461
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6462</div>
6463
6464<!-- _______________________________________________________________________ -->
6465<div class="doc_subsubsection">
6466 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6467</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6468
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6469<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6470
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6471<h5>Syntax:</h5>
6472<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6473 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]6474</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6475
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6476<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6477<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6478 function pointer suitable for executing it.</p>
6479
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6480<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6481<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6482 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6483 sufficiently aligned block of memory; this memory is written to by the
6484 intrinsic. Note that the size and the alignment are target-specific - LLVM
6485 currently provides no portable way of determining them, so a front-end that
6486 generates this intrinsic needs to have some target-specific knowledge.
6487 The <tt>func</tt> argument must hold a function bitcast to
6488 an <tt>i8*</tt>.</p>
6489
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6490<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6491<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6492 dependent code, turning it into a function. A pointer to this function is
6493 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6494 function pointer type</a> before being called. The new function's signature
6495 is the same as that of <tt>func</tt> with any arguments marked with
6496 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6497 is allowed, and it must be of pointer type. Calling the new function is
6498 equivalent to calling <tt>func</tt> with the same argument list, but
6499 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6500 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6501 by <tt>tramp</tt> is modified, then the effect of any later call to the
6502 returned function pointer is undefined.</p>
6503
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6504</div>
6505
6506<!-- ======================================================================= -->
6507<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6508 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6509</div>
6510
6511<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6512
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6513<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6514 hardware constructs for atomic operations and memory synchronization. This
6515 provides an interface to the hardware, not an interface to the programmer. It
6516 is aimed at a low enough level to allow any programming models or APIs
6517 (Application Programming Interfaces) which need atomic behaviors to map
6518 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6519 hardware provides a "universal IR" for source languages, it also provides a
6520 starting point for developing a "universal" atomic operation and
6521 synchronization IR.</p>
6522
6523<p>These do <em>not</em> form an API such as high-level threading libraries,
6524 software transaction memory systems, atomic primitives, and intrinsic
6525 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6526 application libraries. The hardware interface provided by LLVM should allow
6527 a clean implementation of all of these APIs and parallel programming models.
6528 No one model or paradigm should be selected above others unless the hardware
6529 itself ubiquitously does so.</p>
6530
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6531</div>
6532
6533<!-- _______________________________________________________________________ -->
6534<div class="doc_subsubsection">
6535 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6536</div>
6537<div class="doc_text">
6538<h5>Syntax:</h5>
6539<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6540 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]6541</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6542
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6543<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6544<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6545 specific pairs of memory access types.</p>
6546
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6547<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6548<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6549 The first four arguments enables a specific barrier as listed below. The
6550 fith argument specifies that the barrier applies to io or device or uncached
6551 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6552
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6553<ul>
6554 <li><tt>ll</tt>: load-load barrier</li>
6555 <li><tt>ls</tt>: load-store barrier</li>
6556 <li><tt>sl</tt>: store-load barrier</li>
6557 <li><tt>ss</tt>: store-store barrier</li>
6558 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6559</ul>
6560
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6561<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6562<p>This intrinsic causes the system to enforce some ordering constraints upon
6563 the loads and stores of the program. This barrier does not
6564 indicate <em>when</em> any events will occur, it only enforces
6565 an <em>order</em> in which they occur. For any of the specified pairs of load
6566 and store operations (f.ex. load-load, or store-load), all of the first
6567 operations preceding the barrier will complete before any of the second
6568 operations succeeding the barrier begin. Specifically the semantics for each
6569 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6570
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6571<ul>
6572 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6573 after the barrier begins.</li>
6574 <li><tt>ls</tt>: All loads before the barrier must complete before any
6575 store after the barrier begins.</li>
6576 <li><tt>ss</tt>: All stores before the barrier must complete before any
6577 store after the barrier begins.</li>
6578 <li><tt>sl</tt>: All stores before the barrier must complete before any
6579 load after the barrier begins.</li>
6580</ul>
6581
6582<p>These semantics are applied with a logical "and" behavior when more than one
6583 is enabled in a single memory barrier intrinsic.</p>
6584
6585<p>Backends may implement stronger barriers than those requested when they do
6586 not support as fine grained a barrier as requested. Some architectures do
6587 not need all types of barriers and on such architectures, these become
6588 noops.</p>
6589
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6590<h5>Example:</h5>
6591<pre>
6592%ptr = malloc i32
6593 store i32 4, %ptr
6594
6595%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6596 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6597 <i>; guarantee the above finishes</i>
6598 store i32 8, %ptr <i>; before this begins</i>
6599</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6600
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6601</div>
6602
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6603<!-- _______________________________________________________________________ -->
6604<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6605 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6606</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6607
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6608<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6609
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6610<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6611<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6612 any integer bit width and for different address spaces. Not all targets
6613 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6614
6615<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6616 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6617 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6618 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6619 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]6620</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6621
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6622<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6623<p>This loads a value in memory and compares it to a given value. If they are
6624 equal, it stores a new value into the memory.</p>
6625
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6626<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6627<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6628 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6629 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6630 this integer type. While any bit width integer may be used, targets may only
6631 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6632
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6633<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6634<p>This entire intrinsic must be executed atomically. It first loads the value
6635 in memory pointed to by <tt>ptr</tt> and compares it with the
6636 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6637 memory. The loaded value is yielded in all cases. This provides the
6638 equivalent of an atomic compare-and-swap operation within the SSA
6639 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6640
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6641<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6642<pre>
6643%ptr = malloc i32
6644 store i32 4, %ptr
6645
6646%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6647%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6648 <i>; yields {i32}:result1 = 4</i>
6649%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6650%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6651
6652%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6653%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6654 <i>; yields {i32}:result2 = 8</i>
6655%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6656
6657%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6658</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6659
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6660</div>
6661
6662<!-- _______________________________________________________________________ -->
6663<div class="doc_subsubsection">
6664 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6665</div>
6666<div class="doc_text">
6667<h5>Syntax:</h5>
6668
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6669<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6670 integer bit width. Not all targets support all bit widths however.</p>
6671
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6672<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6673 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6674 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6675 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6676 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]6677</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6678
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6679<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6680<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6681 the value from memory. It then stores the value in <tt>val</tt> in the memory
6682 at <tt>ptr</tt>.</p>
6683
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6684<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6685<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6686 the <tt>val</tt> argument and the result must be integers of the same bit
6687 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6688 integer type. The targets may only lower integer representations they
6689 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6690
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6691<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6692<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6693 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6694 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6695
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6696<h5>Examples:</h5>
6697<pre>
6698%ptr = malloc i32
6699 store i32 4, %ptr
6700
6701%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6702%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6703 <i>; yields {i32}:result1 = 4</i>
6704%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6705%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6706
6707%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6708%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6709 <i>; yields {i32}:result2 = 8</i>
6710
6711%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6712%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6713</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6714
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6715</div>
6716
6717<!-- _______________________________________________________________________ -->
6718<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6719 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6720
6721</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6722
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6723<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6724
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6725<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6726<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6727 any integer bit width. Not all targets support all bit widths however.</p>
6728
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6729<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6730 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6731 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6732 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6733 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]6734</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6735
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6736<h5>Overview:</h5>
6737<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6738 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6739
6740<h5>Arguments:</h5>
6741<p>The intrinsic takes two arguments, the first a pointer to an integer value
6742 and the second an integer value. The result is also an integer value. These
6743 integer types can have any bit width, but they must all have the same bit
6744 width. The targets may only lower integer representations they support.</p>
6745
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6746<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6747<p>This intrinsic does a series of operations atomically. It first loads the
6748 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6749 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]6750
6751<h5>Examples:</h5>
6752<pre>
6753%ptr = malloc i32
6754 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6755%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6756 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6757%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6758 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6759%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6760 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6761%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6762</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6763
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6764</div>
6765
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6766<!-- _______________________________________________________________________ -->
6767<div class="doc_subsubsection">
6768 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6769
6770</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6771
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6772<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6773
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6774<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6775<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6776 any integer bit width and for different address spaces. Not all targets
6777 support all bit widths however.</p>
6778
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6779<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6780 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6781 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6782 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6783 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]6784</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6785
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6786<h5>Overview:</h5>
6787<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6788 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6789
6790<h5>Arguments:</h5>
6791<p>The intrinsic takes two arguments, the first a pointer to an integer value
6792 and the second an integer value. The result is also an integer value. These
6793 integer types can have any bit width, but they must all have the same bit
6794 width. The targets may only lower integer representations they support.</p>
6795
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6796<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6797<p>This intrinsic does a series of operations atomically. It first loads the
6798 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6799 result to <tt>ptr</tt>. It yields the original value stored
6800 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6801
6802<h5>Examples:</h5>
6803<pre>
6804%ptr = malloc i32
6805 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6806%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6807 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6808%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6809 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6810%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6811 <i>; yields {i32}:result3 = 2</i>
6812%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6813</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6814
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6815</div>
6816
6817<!-- _______________________________________________________________________ -->
6818<div class="doc_subsubsection">
6819 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6820 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6821 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6822 <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]6823</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6824
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6825<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6826
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6827<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6828<p>These are overloaded intrinsics. You can
6829 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6830 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6831 bit width and for different address spaces. Not all targets support all bit
6832 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6833
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6834<pre>
6835 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6836 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6837 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6838 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]6839</pre>
6840
6841<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6842 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6843 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6844 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6845 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]6846</pre>
6847
6848<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6849 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6850 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6851 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6852 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]6853</pre>
6854
6855<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6856 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6857 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6858 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6859 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]6860</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6861
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6862<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6863<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6864 the value stored in memory at <tt>ptr</tt>. It yields the original value
6865 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6866
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6867<h5>Arguments:</h5>
6868<p>These intrinsics take two arguments, the first a pointer to an integer value
6869 and the second an integer value. The result is also an integer value. These
6870 integer types can have any bit width, but they must all have the same bit
6871 width. The targets may only lower integer representations they support.</p>
6872
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6873<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6874<p>These intrinsics does a series of operations atomically. They first load the
6875 value stored at <tt>ptr</tt>. They then do the bitwise
6876 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6877 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6878
6879<h5>Examples:</h5>
6880<pre>
6881%ptr = malloc i32
6882 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6883%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6884 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6885%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6886 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6887%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6888 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6889%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6890 <i>; yields {i32}:result3 = FF</i>
6891%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6892</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6893
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6894</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6895
6896<!-- _______________________________________________________________________ -->
6897<div class="doc_subsubsection">
6898 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6899 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6900 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6901 <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]6902</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6903
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6904<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6905
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6906<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6907<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6908 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6909 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6910 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6911
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6912<pre>
6913 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6914 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6915 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6916 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]6917</pre>
6918
6919<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6920 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6921 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6922 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6923 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]6924</pre>
6925
6926<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6927 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6928 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6929 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6930 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]6931</pre>
6932
6933<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6934 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6935 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6936 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6937 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]6938</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6939
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6940<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6941<p>These intrinsics takes the signed or unsigned minimum or maximum of
6942 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6943 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6944
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6945<h5>Arguments:</h5>
6946<p>These intrinsics take two arguments, the first a pointer to an integer value
6947 and the second an integer value. The result is also an integer value. These
6948 integer types can have any bit width, but they must all have the same bit
6949 width. The targets may only lower integer representations they support.</p>
6950
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6951<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6952<p>These intrinsics does a series of operations atomically. They first load the
6953 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6954 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6955 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6956
6957<h5>Examples:</h5>
6958<pre>
6959%ptr = malloc i32
6960 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6961%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6962 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6963%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6964 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6965%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6966 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6967%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6968 <i>; yields {i32}:result3 = 8</i>
6969%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6970</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6971
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6972</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6973
6974<!-- ======================================================================= -->
6975<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6976 <a name="int_general">General Intrinsics</a>
6977</div>
6978
6979<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6980
6981<p>This class of intrinsics is designed to be generic and has no specific
6982 purpose.</p>
6983
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6984</div>
6985
6986<!-- _______________________________________________________________________ -->
6987<div class="doc_subsubsection">
6988 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6989</div>
6990
6991<div class="doc_text">
6992
6993<h5>Syntax:</h5>
6994<pre>
6995 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6996</pre>
6997
6998<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6999<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7000
7001<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7002<p>The first argument is a pointer to a value, the second is a pointer to a
7003 global string, the third is a pointer to a global string which is the source
7004 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7005
7006<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7007<p>This intrinsic allows annotation of local variables with arbitrary strings.
7008 This can be useful for special purpose optimizations that want to look for
7009 these annotations. These have no other defined use, they are ignored by code
7010 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7011
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7012</div>
7013
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7014<!-- _______________________________________________________________________ -->
7015<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7016 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7017</div>
7018
7019<div class="doc_text">
7020
7021<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7022<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7023 any integer bit width.</p>
7024
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7025<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7026 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7027 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7028 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7029 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7030 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]7031</pre>
7032
7033<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7034<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7035
7036<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7037<p>The first argument is an integer value (result of some expression), the
7038 second is a pointer to a global string, the third is a pointer to a global
7039 string which is the source file name, and the last argument is the line
7040 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7041
7042<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7043<p>This intrinsic allows annotations to be put on arbitrary expressions with
7044 arbitrary strings. This can be useful for special purpose optimizations that
7045 want to look for these annotations. These have no other defined use, they
7046 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7047
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7048</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7049
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7050<!-- _______________________________________________________________________ -->
7051<div class="doc_subsubsection">
7052 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7053</div>
7054
7055<div class="doc_text">
7056
7057<h5>Syntax:</h5>
7058<pre>
7059 declare void @llvm.trap()
7060</pre>
7061
7062<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7063<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7064
7065<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7066<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7067
7068<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7069<p>This intrinsics is lowered to the target dependent trap instruction. If the
7070 target does not have a trap instruction, this intrinsic will be lowered to
7071 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7072
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7073</div>
7074
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7075<!-- _______________________________________________________________________ -->
7076<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7077 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7078</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7079
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7080<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7081
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7082<h5>Syntax:</h5>
7083<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7084 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7085</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7086
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7087<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7088<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7089 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7090 ensure that it is placed on the stack before local variables.</p>
7091
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7092<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7093<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7094 arguments. The first argument is the value loaded from the stack
7095 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7096 that has enough space to hold the value of the guard.</p>
7097
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7098<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7099<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7100 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7101 stack. This is to ensure that if a local variable on the stack is
7102 overwritten, it will destroy the value of the guard. When the function exits,
7103 the guard on the stack is checked against the original guard. If they're
7104 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7105 function.</p>
7106
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7107</div>
7108
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7109<!-- *********************************************************************** -->
7110<hr>
7111<address>
7112 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7113 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7114 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7115 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]7116
7117 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7118 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7119 Last modified: $Date$
7120</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7121
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7122</body>
7123</html>