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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 9d1e4fa6fdfac2bd80e049ef298365d764553302 / . / 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 Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame^]2024<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]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
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame^]2061such, it is unsafe to optimize or assume that the result of the and is undef.
2062However, it is safe to assume that all bits of the undef could be 0, and
2063optimize the and to 0. Likewise, it is safe to assume that all the bits of
2064the undef operand to the or could be set, allowing the or to be folded to
2065-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2066
2067<div class="doc_code">
2068<pre>
2069 %A = select undef, %X, %Y
2070 %B = select undef, 42, %Y
2071 %C = select %X, %Y, undef
2072Safe:
2073 %A = %X (or %Y)
2074 %B = 42 (or %Y)
2075 %C = %Y
2076Unsafe:
2077 %A = undef
2078 %B = undef
2079 %C = undef
2080</pre>
2081</div>
2082
2083<p>This set of examples show that undefined select (and conditional branch)
2084conditions can go "either way" but they have to come from one of the two
2085operands. In the %A example, if %X and %Y were both known to have a clear low
2086bit, then %A would have to have a cleared low bit. However, in the %C example,
2087the optimizer is allowed to assume that the undef operand could be the same as
2088%Y, allowing the whole select to be eliminated.</p>
2089
2090
2091<div class="doc_code">
2092<pre>
2093 %A = xor undef, undef
2094
2095 %B = undef
2096 %C = xor %B, %B
2097
2098 %D = undef
2099 %E = icmp lt %D, 4
2100 %F = icmp gte %D, 4
2101
2102Safe:
2103 %A = undef
2104 %B = undef
2105 %C = undef
2106 %D = undef
2107 %E = undef
2108 %F = undef
2109</pre>
2110</div>
2111
2112<p>This example points out that two undef operands are not necessarily the same.
2113This can be surprising to people (and also matches C semantics) where they
2114assume that "X^X" is always zero, even if X is undef. This isn't true for a
2115number of reasons, but the short answer is that an undef "variable" can
2116arbitrarily change its value over its "live range". This is true because the
2117"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2118logically read from arbitrary registers that happen to be around when needed,
2119so the value is not neccesarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2120to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2121would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2122
2123<div class="doc_code">
2124<pre>
2125 %A = fdiv undef, %X
2126 %B = fdiv %X, undef
2127Safe:
2128 %A = undef
2129b: unreachable
2130</pre>
2131</div>
2132
2133<p>These examples show the crucial difference between an <em>undefined
2134value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2135allowed to have an arbitrary bit-pattern. This means that the %A operation
2136can be constant folded to undef because the undef could be an SNaN, and fdiv is
2137not (currently) defined on SNaN's. However, in the second example, we can make
2138a more aggressive assumption: because the undef is allowed to be an arbitrary
2139value, we are allowed to assume that it could be zero. Since a divide by zero
Chris Lattner83d45d72009-09-08 19:45:34 +0000[diff] [blame]2140has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2141does not execute at all. This allows us to delete the divide and all code after
2142it: since the undefined operation "can't happen", the optimizer can assume that
2143it occurs in dead code.
2144</p>
2145
2146<div class="doc_code">
2147<pre>
2148a: store undef -> %X
2149b: store %X -> undef
2150Safe:
2151a: &lt;deleted&gt;
2152b: unreachable
2153</pre>
2154</div>
2155
2156<p>These examples reiterate the fdiv example: a store "of" an undefined value
2157can be assumed to not have any effect: we can assume that the value is
2158overwritten with bits that happen to match what was already there. However, a
2159store "to" an undefined location could clobber arbitrary memory, therefore, it
2160has undefined behavior.</p>
2161
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2162</div>
2163
2164<!-- ======================================================================= -->
2165<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2166</div>
2167
2168<div class="doc_text">
2169
2170<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2171 to be used as constants. Constant expressions may be of
2172 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2173 operation that does not have side effects (e.g. load and call are not
2174 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2175
2176<dl>
2177 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2178 <dd>Truncate a constant to another type. The bit size of CST must be larger
2179 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2180
2181 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2182 <dd>Zero extend a constant to another type. The bit size of CST must be
2183 smaller or equal to the bit size of TYPE. Both types must be
2184 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2185
2186 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2187 <dd>Sign extend a constant to another type. The bit size of CST must be
2188 smaller or equal to the bit size of TYPE. Both types must be
2189 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2190
2191 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2192 <dd>Truncate a floating point constant to another floating point type. The
2193 size of CST must be larger than the size of TYPE. Both types must be
2194 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2195
2196 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2197 <dd>Floating point extend a constant to another type. The size of CST must be
2198 smaller or equal to the size of TYPE. Both types must be floating
2199 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2200
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2201 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2202 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2203 constant. TYPE must be a scalar or vector integer type. CST must be of
2204 scalar or vector floating point type. Both CST and TYPE must be scalars,
2205 or vectors of the same number of elements. If the value won't fit in the
2206 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2207
2208 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2209 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2210 constant. TYPE must be a scalar or vector integer type. CST must be of
2211 scalar or vector floating point type. Both CST and TYPE must be scalars,
2212 or vectors of the same number of elements. If the value won't fit in the
2213 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2214
2215 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2216 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2217 constant. TYPE must be a scalar or vector floating point type. CST must be
2218 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2219 vectors of the same number of elements. If the value won't fit in the
2220 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2221
2222 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2223 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2224 constant. TYPE must be a scalar or vector floating point type. CST must be
2225 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2226 vectors of the same number of elements. If the value won't fit in the
2227 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2228
2229 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2230 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2231 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2232 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2233 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2234
2235 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2236 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2237 type. CST must be of integer type. The CST value is zero extended,
2238 truncated, or unchanged to make it fit in a pointer size. This one is
2239 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2240
2241 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2242 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2243 are the same as those for the <a href="#i_bitcast">bitcast
2244 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2245
2246 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2247 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2248 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2249 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2250 instruction, the index list may have zero or more indexes, which are
2251 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2252
2253 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2254 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2255
2256 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2257 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2258
2259 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2260 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2261
2262 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2263 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2264 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2265
2266 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2267 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2268 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2269
2270 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2271 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2272 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2273
2274 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2275 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2276 be any of the <a href="#binaryops">binary</a>
2277 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2278 on operands are the same as those for the corresponding instruction
2279 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2280</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2281
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2282</div>
2283
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2284<!-- ======================================================================= -->
2285<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2286</div>
2287
2288<div class="doc_text">
2289
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2290<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2291 stream without affecting the behaviour of the program. There are two
2292 metadata primitives, strings and nodes. All metadata has the
2293 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2294 point ('<tt>!</tt>').</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2295
2296<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2297 any character by escaping non-printable characters with "\xx" where "xx" is
2298 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2299
2300<p>Metadata nodes are represented with notation similar to structure constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2301 (a comma separated list of elements, surrounded by braces and preceeded by an
2302 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2303 10}</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2304
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2305<p>A metadata node will attempt to track changes to the values it holds. In the
2306 event that a value is deleted, it will be replaced with a typeless
2307 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2308
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2309<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2310 the program that isn't available in the instructions, or that isn't easily
2311 computable. Similarly, the code generator may expect a certain metadata
2312 format to be used to express debugging information.</p>
2313
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2314</div>
2315
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2316<!-- *********************************************************************** -->
2317<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2318<!-- *********************************************************************** -->
2319
2320<!-- ======================================================================= -->
2321<div class="doc_subsection">
2322<a name="inlineasm">Inline Assembler Expressions</a>
2323</div>
2324
2325<div class="doc_text">
2326
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2327<p>LLVM supports inline assembler expressions (as opposed
2328 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2329 a special value. This value represents the inline assembler as a string
2330 (containing the instructions to emit), a list of operand constraints (stored
2331 as a string), and a flag that indicates whether or not the inline asm
2332 expression has side effects. An example inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2333
2334<div class="doc_code">
2335<pre>
2336i32 (i32) asm "bswap $0", "=r,r"
2337</pre>
2338</div>
2339
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2340<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2341 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2342 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2343
2344<div class="doc_code">
2345<pre>
2346%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2347</pre>
2348</div>
2349
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2350<p>Inline asms with side effects not visible in the constraint list must be
2351 marked as having side effects. This is done through the use of the
2352 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2353
2354<div class="doc_code">
2355<pre>
2356call void asm sideeffect "eieio", ""()
2357</pre>
2358</div>
2359
2360<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2361 documented here. Constraints on what can be done (e.g. duplication, moving,
2362 etc need to be documented). This is probably best done by reference to
2363 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2364
2365</div>
2366
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2367
2368<!-- *********************************************************************** -->
2369<div class="doc_section">
2370 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2371</div>
2372<!-- *********************************************************************** -->
2373
2374<p>LLVM has a number of "magic" global variables that contain data that affect
2375code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2376of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2377section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2378by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2379
2380<!-- ======================================================================= -->
2381<div class="doc_subsection">
2382<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2383</div>
2384
2385<div class="doc_text">
2386
2387<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2388href="#linkage_appending">appending linkage</a>. This array contains a list of
2389pointers to global variables and functions which may optionally have a pointer
2390cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2391
2392<pre>
2393 @X = global i8 4
2394 @Y = global i32 123
2395
2396 @llvm.used = appending global [2 x i8*] [
2397 i8* @X,
2398 i8* bitcast (i32* @Y to i8*)
2399 ], section "llvm.metadata"
2400</pre>
2401
2402<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2403compiler, assembler, and linker are required to treat the symbol as if there is
2404a reference to the global that it cannot see. For example, if a variable has
2405internal linkage and no references other than that from the <tt>@llvm.used</tt>
2406list, it cannot be deleted. This is commonly used to represent references from
2407inline asms and other things the compiler cannot "see", and corresponds to
2408"attribute((used))" in GNU C.</p>
2409
2410<p>On some targets, the code generator must emit a directive to the assembler or
2411object file to prevent the assembler and linker from molesting the symbol.</p>
2412
2413</div>
2414
2415<!-- ======================================================================= -->
2416<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2417<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2418</div>
2419
2420<div class="doc_text">
2421
2422<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2423<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2424touching the symbol. On targets that support it, this allows an intelligent
2425linker to optimize references to the symbol without being impeded as it would be
2426by <tt>@llvm.used</tt>.</p>
2427
2428<p>This is a rare construct that should only be used in rare circumstances, and
2429should not be exposed to source languages.</p>
2430
2431</div>
2432
2433<!-- ======================================================================= -->
2434<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2435<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2436</div>
2437
2438<div class="doc_text">
2439
2440<p>TODO: Describe this.</p>
2441
2442</div>
2443
2444<!-- ======================================================================= -->
2445<div class="doc_subsection">
2446<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2447</div>
2448
2449<div class="doc_text">
2450
2451<p>TODO: Describe this.</p>
2452
2453</div>
2454
2455
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2456<!-- *********************************************************************** -->
2457<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2458<!-- *********************************************************************** -->
2459
2460<div class="doc_text">
2461
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2462<p>The LLVM instruction set consists of several different classifications of
2463 instructions: <a href="#terminators">terminator
2464 instructions</a>, <a href="#binaryops">binary instructions</a>,
2465 <a href="#bitwiseops">bitwise binary instructions</a>,
2466 <a href="#memoryops">memory instructions</a>, and
2467 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2468
2469</div>
2470
2471<!-- ======================================================================= -->
2472<div class="doc_subsection"> <a name="terminators">Terminator
2473Instructions</a> </div>
2474
2475<div class="doc_text">
2476
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2477<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2478 in a program ends with a "Terminator" instruction, which indicates which
2479 block should be executed after the current block is finished. These
2480 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2481 control flow, not values (the one exception being the
2482 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2483
2484<p>There are six different terminator instructions: the
2485 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2486 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2487 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
2488 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2489 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2490 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2491
2492</div>
2493
2494<!-- _______________________________________________________________________ -->
2495<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2496Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2497
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2498<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2499
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2500<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2501<pre>
2502 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]2503 ret void <i>; Return from void function</i>
2504</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2505
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2506<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2507<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2508 a value) from a function back to the caller.</p>
2509
2510<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2511 value and then causes control flow, and one that just causes control flow to
2512 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2513
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2514<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2515<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2516 return value. The type of the return value must be a
2517 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2518
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2519<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2520 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2521 value or a return value with a type that does not match its type, or if it
2522 has a void return type and contains a '<tt>ret</tt>' instruction with a
2523 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2524
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2525<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2526<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2527 the calling function's context. If the caller is a
2528 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2529 instruction after the call. If the caller was an
2530 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2531 the beginning of the "normal" destination block. If the instruction returns
2532 a value, that value shall set the call or invoke instruction's return
2533 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2534
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2535<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2536<pre>
2537 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2538 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2539 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]2540</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2541
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2542<p>Note that the code generator does not yet fully support large
2543 return values. The specific sizes that are currently supported are
2544 dependent on the target. For integers, on 32-bit targets the limit
2545 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2546 For aggregate types, the current limits are dependent on the element
2547 types; for example targets are often limited to 2 total integer
2548 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2549
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2550</div>
2551<!-- _______________________________________________________________________ -->
2552<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2553
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2554<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2555
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2556<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2557<pre>
2558 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]2559</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2560
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2561<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2562<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2563 different basic block in the current function. There are two forms of this
2564 instruction, corresponding to a conditional branch and an unconditional
2565 branch.</p>
2566
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2567<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2568<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2569 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2570 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2571 target.</p>
2572
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2573<h5>Semantics:</h5>
2574<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2575 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2576 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2577 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2578
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2579<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2580<pre>
2581Test:
2582 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2583 br i1 %cond, label %IfEqual, label %IfUnequal
2584IfEqual:
2585 <a href="#i_ret">ret</a> i32 1
2586IfUnequal:
2587 <a href="#i_ret">ret</a> i32 0
2588</pre>
2589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2590</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2591
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2592<!-- _______________________________________________________________________ -->
2593<div class="doc_subsubsection">
2594 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2595</div>
2596
2597<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2598
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2599<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2600<pre>
2601 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2602</pre>
2603
2604<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2605<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]2606 several different places. It is a generalization of the '<tt>br</tt>'
2607 instruction, allowing a branch to occur to one of many possible
2608 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2609
2610<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2611<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2612 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2613 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2614 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2615
2616<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2617<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2618 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2619 is searched for the given value. If the value is found, control flow is
2620 transfered to the corresponding destination; otherwise, control flow is
2621 transfered to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2622
2623<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2624<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2625 <tt>switch</tt> instruction, this instruction may be code generated in
2626 different ways. For example, it could be generated as a series of chained
2627 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2628
2629<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2630<pre>
2631 <i>; Emulate a conditional br instruction</i>
2632 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2633 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2634
2635 <i>; Emulate an unconditional br instruction</i>
2636 switch i32 0, label %dest [ ]
2637
2638 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2639 switch i32 %val, label %otherwise [ i32 0, label %onzero
2640 i32 1, label %onone
2641 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2642</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2643
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2644</div>
2645
2646<!-- _______________________________________________________________________ -->
2647<div class="doc_subsubsection">
2648 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2649</div>
2650
2651<div class="doc_text">
2652
2653<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2654<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2655 &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]2656 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2657</pre>
2658
2659<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2660<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2661 function, with the possibility of control flow transfer to either the
2662 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2663 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2664 control flow will return to the "normal" label. If the callee (or any
2665 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2666 instruction, control is interrupted and continued at the dynamically nearest
2667 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2668
2669<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2670<p>This instruction requires several arguments:</p>
2671
2672<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2673 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2674 convention</a> the call should use. If none is specified, the call
2675 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2676
2677 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2678 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2679 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2680
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2681 <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]2682 function value being invoked. In most cases, this is a direct function
2683 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2684 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2685
2686 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2687 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2688
2689 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2690 signature argument types. If the function signature indicates the
2691 function accepts a variable number of arguments, the extra arguments can
2692 be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2693
2694 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2695 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2696
2697 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2698 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2699
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2700 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2701 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2702 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2703</ol>
2704
2705<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2706<p>This instruction is designed to operate as a standard
2707 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2708 primary difference is that it establishes an association with a label, which
2709 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2710
2711<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2712 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2713 exception. Additionally, this is important for implementation of
2714 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2715
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2716<p>For the purposes of the SSA form, the definition of the value returned by the
2717 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2718 block to the "normal" label. If the callee unwinds then no return value is
2719 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2720
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2721<h5>Example:</h5>
2722<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2723 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2724 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2725 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2726 unwind label %TestCleanup <i>; {i32}:retval set</i>
2727</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2728
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2729</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2730
2731<!-- _______________________________________________________________________ -->
2732
2733<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2734Instruction</a> </div>
2735
2736<div class="doc_text">
2737
2738<h5>Syntax:</h5>
2739<pre>
2740 unwind
2741</pre>
2742
2743<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2744<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2745 at the first callee in the dynamic call stack which used
2746 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2747 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2748
2749<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2750<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2751 immediately halt. The dynamic call stack is then searched for the
2752 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2753 Once found, execution continues at the "exceptional" destination block
2754 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2755 instruction in the dynamic call chain, undefined behavior results.</p>
2756
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2757</div>
2758
2759<!-- _______________________________________________________________________ -->
2760
2761<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2762Instruction</a> </div>
2763
2764<div class="doc_text">
2765
2766<h5>Syntax:</h5>
2767<pre>
2768 unreachable
2769</pre>
2770
2771<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2772<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2773 instruction is used to inform the optimizer that a particular portion of the
2774 code is not reachable. This can be used to indicate that the code after a
2775 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2776
2777<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2778<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2779
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2780</div>
2781
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2782<!-- ======================================================================= -->
2783<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2784
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2785<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2786
2787<p>Binary operators are used to do most of the computation in a program. They
2788 require two operands of the same type, execute an operation on them, and
2789 produce a single value. The operands might represent multiple data, as is
2790 the case with the <a href="#t_vector">vector</a> data type. The result value
2791 has the same type as its operands.</p>
2792
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2793<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2794
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2795</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2796
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2797<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2798<div class="doc_subsubsection">
2799 <a name="i_add">'<tt>add</tt>' Instruction</a>
2800</div>
2801
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2802<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2803
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2804<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2805<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2806 &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]2807 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2808 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2809 &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]2810</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2811
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2812<h5>Overview:</h5>
2813<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2814
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2815<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2816<p>The two arguments to the '<tt>add</tt>' instruction must
2817 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2818 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2819
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2820<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2821<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2822
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2823<p>If the sum has unsigned overflow, the result returned is the mathematical
2824 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]2825
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2826<p>Because LLVM integers use a two's complement representation, this instruction
2827 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2828
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2829<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2830 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2831 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2832 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2833
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2834<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2835<pre>
2836 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2837</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2838
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2839</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2840
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2841<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2842<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2843 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2844</div>
2845
2846<div class="doc_text">
2847
2848<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2849<pre>
2850 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2851</pre>
2852
2853<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2854<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2855
2856<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2857<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2858 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2859 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2860
2861<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2862<p>The value produced is the floating point sum of the two operands.</p>
2863
2864<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2865<pre>
2866 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2867</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2868
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2869</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2870
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2871<!-- _______________________________________________________________________ -->
2872<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2873 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2874</div>
2875
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2876<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2877
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2878<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2879<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2880 &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]2881 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2882 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2883 &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]2884</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2885
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2886<h5>Overview:</h5>
2887<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2888 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2889
2890<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2891 '<tt>neg</tt>' instruction present in most other intermediate
2892 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2893
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2894<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2895<p>The two arguments to the '<tt>sub</tt>' instruction must
2896 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2897 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2898
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2899<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2900<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2901
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2902<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2903 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2904 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2905
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2906<p>Because LLVM integers use a two's complement representation, this instruction
2907 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2908
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2909<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2910 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2911 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2912 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2913
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2914<h5>Example:</h5>
2915<pre>
2916 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2917 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2918</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2919
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2920</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2921
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2922<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2923<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2924 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2925</div>
2926
2927<div class="doc_text">
2928
2929<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2930<pre>
2931 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2932</pre>
2933
2934<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2935<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2936 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2937
2938<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2939 '<tt>fneg</tt>' instruction present in most other intermediate
2940 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2941
2942<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2943<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2944 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2945 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2946
2947<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2948<p>The value produced is the floating point difference of the two operands.</p>
2949
2950<h5>Example:</h5>
2951<pre>
2952 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2953 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2954</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2955
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2956</div>
2957
2958<!-- _______________________________________________________________________ -->
2959<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2960 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2961</div>
2962
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2963<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2964
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2965<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2966<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2967 &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]2968 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2969 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2970 &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]2971</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2972
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2973<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2974<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2975
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2976<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2977<p>The two arguments to the '<tt>mul</tt>' instruction must
2978 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2979 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2980
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2981<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2982<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2983
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2984<p>If the result of the multiplication has unsigned overflow, the result
2985 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
2986 width of the result.</p>
2987
2988<p>Because LLVM integers use a two's complement representation, and the result
2989 is the same width as the operands, this instruction returns the correct
2990 result for both signed and unsigned integers. If a full product
2991 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
2992 be sign-extended or zero-extended as appropriate to the width of the full
2993 product.</p>
2994
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2995<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2996 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2997 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
2998 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2999
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3000<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3001<pre>
3002 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3003</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3004
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3005</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3006
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3007<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3008<div class="doc_subsubsection">
3009 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3010</div>
3011
3012<div class="doc_text">
3013
3014<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3015<pre>
3016 &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]3017</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3018
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3019<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3020<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3021
3022<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3023<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3024 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3025 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3026
3027<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3028<p>The value produced is the floating point product of the two operands.</p>
3029
3030<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3031<pre>
3032 &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]3033</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3034
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3035</div>
3036
3037<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3038<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3039</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3040
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3041<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3042
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3043<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3044<pre>
3045 &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]3046</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3047
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3048<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3049<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3050
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3051<h5>Arguments:</h5>
3052<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3053 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3054 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3055
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3056<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3057<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3058
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3059<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3060 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3061
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3062<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3063
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3064<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3065<pre>
3066 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3067</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3068
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3069</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3070
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3071<!-- _______________________________________________________________________ -->
3072<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3073</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3074
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3075<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3076
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3077<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3078<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3079 &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]3080 &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]3081</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3082
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3083<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3084<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3085
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3086<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3087<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3088 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3089 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3090
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3091<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3092<p>The value produced is the signed integer quotient of the two operands rounded
3093 towards zero.</p>
3094
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3095<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3096 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3097
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3098<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3099 undefined behavior; this is a rare case, but can occur, for example, by doing
3100 a 32-bit division of -2147483648 by -1.</p>
3101
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3102<p>If the <tt>exact</tt> keyword is present, the result value of the
3103 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3104 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3105
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3106<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3107<pre>
3108 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3109</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3110
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3111</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3112
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3113<!-- _______________________________________________________________________ -->
3114<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3115Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3116
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3117<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3118
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3119<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3120<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3121 &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]3122</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3123
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3124<h5>Overview:</h5>
3125<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3126
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3127<h5>Arguments:</h5>
3128<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3129 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3130 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3131
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3132<h5>Semantics:</h5>
3133<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3134
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3135<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3136<pre>
3137 &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]3138</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3139
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3140</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3141
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3142<!-- _______________________________________________________________________ -->
3143<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3144</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3145
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3146<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3147
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3148<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3149<pre>
3150 &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]3151</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3152
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3153<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3154<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3155 division of its two arguments.</p>
3156
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3157<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3158<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3159 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3160 values. Both arguments must have identical types.</p>
3161
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3162<h5>Semantics:</h5>
3163<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3164 This instruction always performs an unsigned division to get the
3165 remainder.</p>
3166
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3167<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3168 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3169
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3170<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3171
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3172<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3173<pre>
3174 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3175</pre>
3176
3177</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3178
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3179<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3180<div class="doc_subsubsection">
3181 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3182</div>
3183
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3184<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3185
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3186<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3187<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3188 &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]3189</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3190
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3191<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3192<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3193 division of its two operands. This instruction can also take
3194 <a href="#t_vector">vector</a> versions of the values in which case the
3195 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3196
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3197<h5>Arguments:</h5>
3198<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3199 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3200 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3201
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3202<h5>Semantics:</h5>
3203<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3204 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3205 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3206 a value. For more information about the difference,
3207 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3208 Math Forum</a>. For a table of how this is implemented in various languages,
3209 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3210 Wikipedia: modulo operation</a>.</p>
3211
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3212<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3213 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3214
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3215<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3216 Overflow also leads to undefined behavior; this is a rare case, but can
3217 occur, for example, by taking the remainder of a 32-bit division of
3218 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3219 lets srem be implemented using instructions that return both the result of
3220 the division and the remainder.)</p>
3221
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3222<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3223<pre>
3224 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3225</pre>
3226
3227</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3228
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3229<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3230<div class="doc_subsubsection">
3231 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3232
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3233<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3234
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3235<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3236<pre>
3237 &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]3238</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3239
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3240<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3241<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3242 its two operands.</p>
3243
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3244<h5>Arguments:</h5>
3245<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3246 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3247 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3248
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3249<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3250<p>This instruction returns the <i>remainder</i> of a division. The remainder
3251 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3252
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3253<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3254<pre>
3255 &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]3256</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3257
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3258</div>
3259
3260<!-- ======================================================================= -->
3261<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3262Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3263
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3264<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3265
3266<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3267 program. They are generally very efficient instructions and can commonly be
3268 strength reduced from other instructions. They require two operands of the
3269 same type, execute an operation on them, and produce a single value. The
3270 resulting value is the same type as its operands.</p>
3271
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3272</div>
3273
3274<!-- _______________________________________________________________________ -->
3275<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3276Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3277
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3278<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3279
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3280<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3281<pre>
3282 &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]3283</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3284
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3285<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3286<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3287 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3288
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3289<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3290<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3291 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3292 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3293
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3294<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3295<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3296 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3297 is (statically or dynamically) negative or equal to or larger than the number
3298 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3299 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3300 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3301
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3302<h5>Example:</h5>
3303<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3304 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3305 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3306 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3307 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3308 &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]3309</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3310
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3311</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3312
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3313<!-- _______________________________________________________________________ -->
3314<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3315Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3316
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3317<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3318
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3319<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3320<pre>
3321 &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]3322</pre>
3323
3324<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3325<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3326 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3327
3328<h5>Arguments:</h5>
3329<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3330 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3331 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3332
3333<h5>Semantics:</h5>
3334<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3335 significant bits of the result will be filled with zero bits after the shift.
3336 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3337 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3338 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3339 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3340
3341<h5>Example:</h5>
3342<pre>
3343 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3344 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3345 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3346 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3347 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3348 &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]3349</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3350
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3351</div>
3352
3353<!-- _______________________________________________________________________ -->
3354<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3355Instruction</a> </div>
3356<div class="doc_text">
3357
3358<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3359<pre>
3360 &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]3361</pre>
3362
3363<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3364<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3365 operand shifted to the right a specified number of bits with sign
3366 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3367
3368<h5>Arguments:</h5>
3369<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3370 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3371 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3372
3373<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3374<p>This instruction always performs an arithmetic shift right operation, The
3375 most significant bits of the result will be filled with the sign bit
3376 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3377 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3378 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3379 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3380
3381<h5>Example:</h5>
3382<pre>
3383 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3384 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3385 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3386 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3387 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3388 &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]3389</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3390
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3391</div>
3392
3393<!-- _______________________________________________________________________ -->
3394<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3395Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3396
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3397<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3398
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3399<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3400<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3401 &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]3402</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3403
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3404<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3405<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3406 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3407
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3408<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3409<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3410 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3411 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3412
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3413<h5>Semantics:</h5>
3414<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3415
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3416<table border="1" cellspacing="0" cellpadding="4">
3417 <tbody>
3418 <tr>
3419 <td>In0</td>
3420 <td>In1</td>
3421 <td>Out</td>
3422 </tr>
3423 <tr>
3424 <td>0</td>
3425 <td>0</td>
3426 <td>0</td>
3427 </tr>
3428 <tr>
3429 <td>0</td>
3430 <td>1</td>
3431 <td>0</td>
3432 </tr>
3433 <tr>
3434 <td>1</td>
3435 <td>0</td>
3436 <td>0</td>
3437 </tr>
3438 <tr>
3439 <td>1</td>
3440 <td>1</td>
3441 <td>1</td>
3442 </tr>
3443 </tbody>
3444</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3445
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3446<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3447<pre>
3448 &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]3449 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3450 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3451</pre>
3452</div>
3453<!-- _______________________________________________________________________ -->
3454<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3455
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3456<div class="doc_text">
3457
3458<h5>Syntax:</h5>
3459<pre>
3460 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3461</pre>
3462
3463<h5>Overview:</h5>
3464<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3465 two operands.</p>
3466
3467<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3468<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3469 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3470 values. Both arguments must have identical types.</p>
3471
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3472<h5>Semantics:</h5>
3473<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3474
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3475<table border="1" cellspacing="0" cellpadding="4">
3476 <tbody>
3477 <tr>
3478 <td>In0</td>
3479 <td>In1</td>
3480 <td>Out</td>
3481 </tr>
3482 <tr>
3483 <td>0</td>
3484 <td>0</td>
3485 <td>0</td>
3486 </tr>
3487 <tr>
3488 <td>0</td>
3489 <td>1</td>
3490 <td>1</td>
3491 </tr>
3492 <tr>
3493 <td>1</td>
3494 <td>0</td>
3495 <td>1</td>
3496 </tr>
3497 <tr>
3498 <td>1</td>
3499 <td>1</td>
3500 <td>1</td>
3501 </tr>
3502 </tbody>
3503</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3504
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3505<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3506<pre>
3507 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3508 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3509 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3510</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3511
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3512</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3513
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3514<!-- _______________________________________________________________________ -->
3515<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3516Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3517
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3518<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3519
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3520<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3521<pre>
3522 &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]3523</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3524
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3525<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3526<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3527 its two operands. The <tt>xor</tt> is used to implement the "one's
3528 complement" operation, which is the "~" operator in C.</p>
3529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3530<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3531<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3532 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3533 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3534
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3535<h5>Semantics:</h5>
3536<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3537
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3538<table border="1" cellspacing="0" cellpadding="4">
3539 <tbody>
3540 <tr>
3541 <td>In0</td>
3542 <td>In1</td>
3543 <td>Out</td>
3544 </tr>
3545 <tr>
3546 <td>0</td>
3547 <td>0</td>
3548 <td>0</td>
3549 </tr>
3550 <tr>
3551 <td>0</td>
3552 <td>1</td>
3553 <td>1</td>
3554 </tr>
3555 <tr>
3556 <td>1</td>
3557 <td>0</td>
3558 <td>1</td>
3559 </tr>
3560 <tr>
3561 <td>1</td>
3562 <td>1</td>
3563 <td>0</td>
3564 </tr>
3565 </tbody>
3566</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3567
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3568<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3569<pre>
3570 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3571 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3572 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3573 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3574</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3575
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3576</div>
3577
3578<!-- ======================================================================= -->
3579<div class="doc_subsection">
3580 <a name="vectorops">Vector Operations</a>
3581</div>
3582
3583<div class="doc_text">
3584
3585<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3586 target-independent manner. These instructions cover the element-access and
3587 vector-specific operations needed to process vectors effectively. While LLVM
3588 does directly support these vector operations, many sophisticated algorithms
3589 will want to use target-specific intrinsics to take full advantage of a
3590 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3591
3592</div>
3593
3594<!-- _______________________________________________________________________ -->
3595<div class="doc_subsubsection">
3596 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3597</div>
3598
3599<div class="doc_text">
3600
3601<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3602<pre>
3603 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3604</pre>
3605
3606<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3607<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3608 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3609
3610
3611<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3612<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3613 of <a href="#t_vector">vector</a> type. The second operand is an index
3614 indicating the position from which to extract the element. The index may be
3615 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3616
3617<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3618<p>The result is a scalar of the same type as the element type of
3619 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3620 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3621 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3622
3623<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3624<pre>
3625 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3626</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3627
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3628</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3629
3630<!-- _______________________________________________________________________ -->
3631<div class="doc_subsubsection">
3632 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3633</div>
3634
3635<div class="doc_text">
3636
3637<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3638<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3639 &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]3640</pre>
3641
3642<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3643<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3644 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3645
3646<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3647<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3648 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3649 whose type must equal the element type of the first operand. The third
3650 operand is an index indicating the position at which to insert the value.
3651 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3652
3653<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3654<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3655 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3656 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3657 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3658
3659<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3660<pre>
3661 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3662</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3663
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3664</div>
3665
3666<!-- _______________________________________________________________________ -->
3667<div class="doc_subsubsection">
3668 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3669</div>
3670
3671<div class="doc_text">
3672
3673<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3674<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3675 &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]3676</pre>
3677
3678<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3679<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3680 from two input vectors, returning a vector with the same element type as the
3681 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3682
3683<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3684<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3685 with types that match each other. The third argument is a shuffle mask whose
3686 element type is always 'i32'. The result of the instruction is a vector
3687 whose length is the same as the shuffle mask and whose element type is the
3688 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3689
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3690<p>The shuffle mask operand is required to be a constant vector with either
3691 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3692
3693<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3694<p>The elements of the two input vectors are numbered from left to right across
3695 both of the vectors. The shuffle mask operand specifies, for each element of
3696 the result vector, which element of the two input vectors the result element
3697 gets. The element selector may be undef (meaning "don't care") and the
3698 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3699
3700<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3701<pre>
3702 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3703 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3704 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3705 &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]3706 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3707 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3708 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3709 &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]3710</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3711
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3712</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3713
3714<!-- ======================================================================= -->
3715<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3716 <a name="aggregateops">Aggregate Operations</a>
3717</div>
3718
3719<div class="doc_text">
3720
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3721<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3722
3723</div>
3724
3725<!-- _______________________________________________________________________ -->
3726<div class="doc_subsubsection">
3727 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3728</div>
3729
3730<div class="doc_text">
3731
3732<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3733<pre>
3734 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3735</pre>
3736
3737<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3738<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3739 or array element from an aggregate value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3740
3741<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3742<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3743 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3744 operands are constant indices to specify which value to extract in a similar
3745 manner as indices in a
3746 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3747
3748<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3749<p>The result is the value at the position in the aggregate specified by the
3750 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3751
3752<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3753<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3754 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3755</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3756
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3757</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3758
3759<!-- _______________________________________________________________________ -->
3760<div class="doc_subsubsection">
3761 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3762</div>
3763
3764<div class="doc_text">
3765
3766<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3767<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3768 &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]3769</pre>
3770
3771<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3772<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3773 array element in an aggregate.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3774
3775
3776<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3777<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3778 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3779 second operand is a first-class value to insert. The following operands are
3780 constant indices indicating the position at which to insert the value in a
3781 similar manner as indices in a
3782 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3783 value to insert must have the same type as the value identified by the
3784 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3785
3786<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3787<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3788 that of <tt>val</tt> except that the value at the position specified by the
3789 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3790
3791<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3792<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3793 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3794</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3795
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3796</div>
3797
3798
3799<!-- ======================================================================= -->
3800<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3801 <a name="memoryops">Memory Access and Addressing Operations</a>
3802</div>
3803
3804<div class="doc_text">
3805
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3806<p>A key design point of an SSA-based representation is how it represents
3807 memory. In LLVM, no memory locations are in SSA form, which makes things
3808 very simple. This section describes how to read, write, allocate, and free
3809 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3810
3811</div>
3812
3813<!-- _______________________________________________________________________ -->
3814<div class="doc_subsubsection">
3815 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3816</div>
3817
3818<div class="doc_text">
3819
3820<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3821<pre>
3822 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3823</pre>
3824
3825<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3826<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3827 returns a pointer to it. The object is always allocated in the generic
3828 address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3829
3830<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3831<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3832 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3833 system and returns a pointer of the appropriate type to the program. If
3834 "NumElements" is specified, it is the number of elements allocated, otherwise
3835 "NumElements" is defaulted to be one. If a constant alignment is specified,
3836 the value result of the allocation is guaranteed to be aligned to at least
3837 that boundary. If not specified, or if zero, the target can choose to align
3838 the allocation on any convenient boundary compatible with the type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3839
3840<p>'<tt>type</tt>' must be a sized type.</p>
3841
3842<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3843<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3844 pointer is returned. The result of a zero byte allocation is undefined. The
3845 result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3846
3847<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3848<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3849 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3850
3851 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3852 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3853 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3854 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3855 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3856</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3857
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3858<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3859
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3860</div>
3861
3862<!-- _______________________________________________________________________ -->
3863<div class="doc_subsubsection">
3864 <a name="i_free">'<tt>free</tt>' Instruction</a>
3865</div>
3866
3867<div class="doc_text">
3868
3869<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3870<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3871 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3872</pre>
3873
3874<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3875<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3876 to be reallocated in the future.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3877
3878<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3879<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3880 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3881
3882<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3883<p>Access to the memory pointed to by the pointer is no longer defined after
3884 this instruction executes. If the pointer is null, the operation is a
3885 noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3886
3887<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3888<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3889 %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]3890 free [4 x i8]* %array
3891</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3892
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3893</div>
3894
3895<!-- _______________________________________________________________________ -->
3896<div class="doc_subsubsection">
3897 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3898</div>
3899
3900<div class="doc_text">
3901
3902<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3903<pre>
3904 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3905</pre>
3906
3907<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3908<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3909 currently executing function, to be automatically released when this function
3910 returns to its caller. The object is always allocated in the generic address
3911 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3912
3913<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3914<p>The '<tt>alloca</tt>' instruction
3915 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3916 runtime stack, returning a pointer of the appropriate type to the program.
3917 If "NumElements" is specified, it is the number of elements allocated,
3918 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3919 specified, the value result of the allocation is guaranteed to be aligned to
3920 at least that boundary. If not specified, or if zero, the target can choose
3921 to align the allocation on any convenient boundary compatible with the
3922 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3923
3924<p>'<tt>type</tt>' may be any sized type.</p>
3925
3926<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3927<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3928 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3929 memory is automatically released when the function returns. The
3930 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3931 variables that must have an address available. When the function returns
3932 (either with the <tt><a href="#i_ret">ret</a></tt>
3933 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3934 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3935
3936<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3937<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3938 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3939 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3940 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3941 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3942</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3943
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3944</div>
3945
3946<!-- _______________________________________________________________________ -->
3947<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3948Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3949
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3950<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3951
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3952<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3953<pre>
3954 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3955 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3956</pre>
3957
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3958<h5>Overview:</h5>
3959<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3960
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3961<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3962<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3963 from which to load. The pointer must point to
3964 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3965 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3966 number or order of execution of this <tt>load</tt> with other
3967 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3968 instructions. </p>
3969
3970<p>The optional constant "align" argument specifies the alignment of the
3971 operation (that is, the alignment of the memory address). A value of 0 or an
3972 omitted "align" argument means that the operation has the preferential
3973 alignment for the target. It is the responsibility of the code emitter to
3974 ensure that the alignment information is correct. Overestimating the
3975 alignment results in an undefined behavior. Underestimating the alignment may
3976 produce less efficient code. An alignment of 1 is always safe.</p>
3977
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3978<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3979<p>The location of memory pointed to is loaded. If the value being loaded is of
3980 scalar type then the number of bytes read does not exceed the minimum number
3981 of bytes needed to hold all bits of the type. For example, loading an
3982 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3983 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3984 is undefined if the value was not originally written using a store of the
3985 same type.</p>
3986
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3987<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3988<pre>
3989 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3990 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3991 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3992</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3993
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3994</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3995
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3996<!-- _______________________________________________________________________ -->
3997<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3998Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3999
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4000<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4001
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4002<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4003<pre>
4004 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]4005 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
4006</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4007
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4008<h5>Overview:</h5>
4009<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4010
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4011<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4012<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4013 and an address at which to store it. The type of the
4014 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4015 the <a href="#t_firstclass">first class</a> type of the
4016 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4017 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4018 or order of execution of this <tt>store</tt> with other
4019 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4020 instructions.</p>
4021
4022<p>The optional constant "align" argument specifies the alignment of the
4023 operation (that is, the alignment of the memory address). A value of 0 or an
4024 omitted "align" argument means that the operation has the preferential
4025 alignment for the target. It is the responsibility of the code emitter to
4026 ensure that the alignment information is correct. Overestimating the
4027 alignment results in an undefined behavior. Underestimating the alignment may
4028 produce less efficient code. An alignment of 1 is always safe.</p>
4029
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4030<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4031<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4032 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4033 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4034 does not exceed the minimum number of bytes needed to hold all bits of the
4035 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4036 writing a value of a type like <tt>i20</tt> with a size that is not an
4037 integral number of bytes, it is unspecified what happens to the extra bits
4038 that do not belong to the type, but they will typically be overwritten.</p>
4039
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4040<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4041<pre>
4042 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4043 store i32 3, i32* %ptr <i>; yields {void}</i>
4044 %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]4045</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4046
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4047</div>
4048
4049<!-- _______________________________________________________________________ -->
4050<div class="doc_subsubsection">
4051 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4052</div>
4053
4054<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4055
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4056<h5>Syntax:</h5>
4057<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4058 &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]4059 &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]4060</pre>
4061
4062<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4063<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4064 subelement of an aggregate data structure. It performs address calculation
4065 only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4066
4067<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4068<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4069 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4070 elements of the aggregate object are indexed. The interpretation of each
4071 index is dependent on the type being indexed into. The first index always
4072 indexes the pointer value given as the first argument, the second index
4073 indexes a value of the type pointed to (not necessarily the value directly
4074 pointed to, since the first index can be non-zero), etc. The first type
4075 indexed into must be a pointer value, subsequent types can be arrays, vectors
4076 and structs. Note that subsequent types being indexed into can never be
4077 pointers, since that would require loading the pointer before continuing
4078 calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4079
4080<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]4081 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4082 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4083 vector, integers of any width are allowed, and they are not required to be
4084 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4085
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4086<p>For example, let's consider a C code fragment and how it gets compiled to
4087 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4088
4089<div class="doc_code">
4090<pre>
4091struct RT {
4092 char A;
4093 int B[10][20];
4094 char C;
4095};
4096struct ST {
4097 int X;
4098 double Y;
4099 struct RT Z;
4100};
4101
4102int *foo(struct ST *s) {
4103 return &amp;s[1].Z.B[5][13];
4104}
4105</pre>
4106</div>
4107
4108<p>The LLVM code generated by the GCC frontend is:</p>
4109
4110<div class="doc_code">
4111<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4112%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4113%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4114
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4115define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4116entry:
4117 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4118 ret i32* %reg
4119}
4120</pre>
4121</div>
4122
4123<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4124<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]4125 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4126 }</tt>' type, a structure. The second index indexes into the third element
4127 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4128 i8 }</tt>' type, another structure. The third index indexes into the second
4129 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4130 array. The two dimensions of the array are subscripted into, yielding an
4131 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4132 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4133
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4134<p>Note that it is perfectly legal to index partially through a structure,
4135 returning a pointer to an inner element. Because of this, the LLVM code for
4136 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4137
4138<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4139 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4140 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4141 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4142 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4143 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4144 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4145 ret i32* %t5
4146 }
4147</pre>
4148
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4149<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4150 <tt>getelementptr</tt> is undefined if the base pointer is not an
4151 <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]4152 that would be formed by successive addition of the offsets implied by the
4153 indices to the base address with infinitely precise arithmetic are not an
4154 <i>in bounds</i> address of that allocated object.
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4155 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4156 that point into the object, plus the address one byte past the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4157
4158<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4159 the base address with silently-wrapping two's complement arithmetic, and
4160 the result value of the <tt>getelementptr</tt> may be outside the object
4161 pointed to by the base pointer. The result value may not necessarily be
4162 used to access memory though, even if it happens to point into allocated
4163 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4164 section for more information.</p>
4165
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4166<p>The getelementptr instruction is often confusing. For some more insight into
4167 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4168
4169<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4170<pre>
4171 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4172 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4173 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4174 %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]4175 <i>; yields i8*:eptr</i>
4176 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4177 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4178 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4179</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4180
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4181</div>
4182
4183<!-- ======================================================================= -->
4184<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4185</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4186
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4187<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4188
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4189<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4190 which all take a single operand and a type. They perform various bit
4191 conversions on the operand.</p>
4192
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4193</div>
4194
4195<!-- _______________________________________________________________________ -->
4196<div class="doc_subsubsection">
4197 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4198</div>
4199<div class="doc_text">
4200
4201<h5>Syntax:</h5>
4202<pre>
4203 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4204</pre>
4205
4206<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4207<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4208 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4209
4210<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4211<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4212 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4213 size and type of the result, which must be
4214 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4215 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4216 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4217
4218<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4219<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4220 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4221 source size must be larger than the destination size, <tt>trunc</tt> cannot
4222 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4223
4224<h5>Example:</h5>
4225<pre>
4226 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4227 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4228 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
4229</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4230
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4231</div>
4232
4233<!-- _______________________________________________________________________ -->
4234<div class="doc_subsubsection">
4235 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4236</div>
4237<div class="doc_text">
4238
4239<h5>Syntax:</h5>
4240<pre>
4241 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4242</pre>
4243
4244<h5>Overview:</h5>
4245<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4246 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4247
4248
4249<h5>Arguments:</h5>
4250<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]4251 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4252 also be of <a href="#t_integer">integer</a> type. The bit size of the
4253 <tt>value</tt> must be smaller than the bit size of the destination type,
4254 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4255
4256<h5>Semantics:</h5>
4257<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]4258 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4259
4260<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4261
4262<h5>Example:</h5>
4263<pre>
4264 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4265 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4266</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4267
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4268</div>
4269
4270<!-- _______________________________________________________________________ -->
4271<div class="doc_subsubsection">
4272 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4273</div>
4274<div class="doc_text">
4275
4276<h5>Syntax:</h5>
4277<pre>
4278 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4279</pre>
4280
4281<h5>Overview:</h5>
4282<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4283
4284<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4285<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4286 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4287 also be of <a href="#t_integer">integer</a> type. The bit size of the
4288 <tt>value</tt> must be smaller than the bit size of the destination type,
4289 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4290
4291<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4292<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4293 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4294 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4295
4296<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4297
4298<h5>Example:</h5>
4299<pre>
4300 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4301 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4302</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4303
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4304</div>
4305
4306<!-- _______________________________________________________________________ -->
4307<div class="doc_subsubsection">
4308 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4309</div>
4310
4311<div class="doc_text">
4312
4313<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4314<pre>
4315 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4316</pre>
4317
4318<h5>Overview:</h5>
4319<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4320 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4321
4322<h5>Arguments:</h5>
4323<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4324 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4325 to cast it to. The size of <tt>value</tt> must be larger than the size of
4326 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4327 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4328
4329<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4330<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4331 <a href="#t_floating">floating point</a> type to a smaller
4332 <a href="#t_floating">floating point</a> type. If the value cannot fit
4333 within the destination type, <tt>ty2</tt>, then the results are
4334 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4335
4336<h5>Example:</h5>
4337<pre>
4338 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4339 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4340</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4341
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4342</div>
4343
4344<!-- _______________________________________________________________________ -->
4345<div class="doc_subsubsection">
4346 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4347</div>
4348<div class="doc_text">
4349
4350<h5>Syntax:</h5>
4351<pre>
4352 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4353</pre>
4354
4355<h5>Overview:</h5>
4356<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]4357 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4358
4359<h5>Arguments:</h5>
4360<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4361 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4362 a <a href="#t_floating">floating point</a> type to cast it to. The source
4363 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4364
4365<h5>Semantics:</h5>
4366<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4367 <a href="#t_floating">floating point</a> type to a larger
4368 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4369 used to make a <i>no-op cast</i> because it always changes bits. Use
4370 <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]4371
4372<h5>Example:</h5>
4373<pre>
4374 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4375 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4376</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4377
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4378</div>
4379
4380<!-- _______________________________________________________________________ -->
4381<div class="doc_subsubsection">
4382 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4383</div>
4384<div class="doc_text">
4385
4386<h5>Syntax:</h5>
4387<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4388 &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]4389</pre>
4390
4391<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4392<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4393 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4394
4395<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4396<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4397 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4398 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4399 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4400 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4401
4402<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4403<p>The '<tt>fptoui</tt>' instruction converts its
4404 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4405 towards zero) unsigned integer value. If the value cannot fit
4406 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4407
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4408<h5>Example:</h5>
4409<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4410 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4411 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4412 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4413</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4414
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4415</div>
4416
4417<!-- _______________________________________________________________________ -->
4418<div class="doc_subsubsection">
4419 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4420</div>
4421<div class="doc_text">
4422
4423<h5>Syntax:</h5>
4424<pre>
4425 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4426</pre>
4427
4428<h5>Overview:</h5>
4429<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4430 <a href="#t_floating">floating point</a> <tt>value</tt> to
4431 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4432
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4433<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4434<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4435 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4436 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4437 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4438 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4439
4440<h5>Semantics:</h5>
4441<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4442 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4443 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4444 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4445
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4446<h5>Example:</h5>
4447<pre>
4448 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4449 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4450 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4451</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4452
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4453</div>
4454
4455<!-- _______________________________________________________________________ -->
4456<div class="doc_subsubsection">
4457 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4458</div>
4459<div class="doc_text">
4460
4461<h5>Syntax:</h5>
4462<pre>
4463 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4464</pre>
4465
4466<h5>Overview:</h5>
4467<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4468 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4469
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4470<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4471<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]4472 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4473 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4474 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4475 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4476
4477<h5>Semantics:</h5>
4478<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4479 integer quantity and converts it to the corresponding floating point
4480 value. If the value cannot fit in the floating point value, the results are
4481 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4482
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4483<h5>Example:</h5>
4484<pre>
4485 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4486 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4487</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4488
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4489</div>
4490
4491<!-- _______________________________________________________________________ -->
4492<div class="doc_subsubsection">
4493 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4494</div>
4495<div class="doc_text">
4496
4497<h5>Syntax:</h5>
4498<pre>
4499 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4500</pre>
4501
4502<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4503<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4504 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4505
4506<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4507<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]4508 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4509 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4510 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4511 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4512
4513<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4514<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4515 quantity and converts it to the corresponding floating point value. If the
4516 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4517
4518<h5>Example:</h5>
4519<pre>
4520 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4521 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4522</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4524</div>
4525
4526<!-- _______________________________________________________________________ -->
4527<div class="doc_subsubsection">
4528 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4529</div>
4530<div class="doc_text">
4531
4532<h5>Syntax:</h5>
4533<pre>
4534 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4535</pre>
4536
4537<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4538<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4539 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4540
4541<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4542<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4543 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4544 <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]4545
4546<h5>Semantics:</h5>
4547<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4548 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4549 truncating or zero extending that value to the size of the integer type. If
4550 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4551 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4552 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4553 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4554
4555<h5>Example:</h5>
4556<pre>
4557 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4558 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4559</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4560
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4561</div>
4562
4563<!-- _______________________________________________________________________ -->
4564<div class="doc_subsubsection">
4565 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4566</div>
4567<div class="doc_text">
4568
4569<h5>Syntax:</h5>
4570<pre>
4571 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4572</pre>
4573
4574<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4575<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4576 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4577
4578<h5>Arguments:</h5>
4579<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4580 value to cast, and a type to cast it to, which must be a
4581 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4582
4583<h5>Semantics:</h5>
4584<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4585 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4586 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4587 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4588 than the size of a pointer then a zero extension is done. If they are the
4589 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4590
4591<h5>Example:</h5>
4592<pre>
4593 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4594 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4595 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4596</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4597
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4598</div>
4599
4600<!-- _______________________________________________________________________ -->
4601<div class="doc_subsubsection">
4602 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4603</div>
4604<div class="doc_text">
4605
4606<h5>Syntax:</h5>
4607<pre>
4608 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4609</pre>
4610
4611<h5>Overview:</h5>
4612<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4613 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4614
4615<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4616<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4617 non-aggregate first class value, and a type to cast it to, which must also be
4618 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4619 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4620 identical. If the source type is a pointer, the destination type must also be
4621 a pointer. This instruction supports bitwise conversion of vectors to
4622 integers and to vectors of other types (as long as they have the same
4623 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4624
4625<h5>Semantics:</h5>
4626<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4627 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4628 this conversion. The conversion is done as if the <tt>value</tt> had been
4629 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4630 be converted to other pointer types with this instruction. To convert
4631 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4632 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4633
4634<h5>Example:</h5>
4635<pre>
4636 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4637 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4638 %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]4639</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4640
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4641</div>
4642
4643<!-- ======================================================================= -->
4644<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4645
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4646<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4647
4648<p>The instructions in this category are the "miscellaneous" instructions, which
4649 defy better classification.</p>
4650
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4651</div>
4652
4653<!-- _______________________________________________________________________ -->
4654<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4655</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4656
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4657<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4658
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4659<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4660<pre>
4661 &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]4662</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4663
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4664<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4665<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4666 boolean values based on comparison of its two integer, integer vector, or
4667 pointer operands.</p>
4668
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4669<h5>Arguments:</h5>
4670<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4671 the condition code indicating the kind of comparison to perform. It is not a
4672 value, just a keyword. The possible condition code are:</p>
4673
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4674<ol>
4675 <li><tt>eq</tt>: equal</li>
4676 <li><tt>ne</tt>: not equal </li>
4677 <li><tt>ugt</tt>: unsigned greater than</li>
4678 <li><tt>uge</tt>: unsigned greater or equal</li>
4679 <li><tt>ult</tt>: unsigned less than</li>
4680 <li><tt>ule</tt>: unsigned less or equal</li>
4681 <li><tt>sgt</tt>: signed greater than</li>
4682 <li><tt>sge</tt>: signed greater or equal</li>
4683 <li><tt>slt</tt>: signed less than</li>
4684 <li><tt>sle</tt>: signed less or equal</li>
4685</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4686
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4687<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4688 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4689 typed. They must also be identical types.</p>
4690
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4691<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4692<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4693 condition code given as <tt>cond</tt>. The comparison performed always yields
4694 either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt>
4695 result, as follows:</p>
4696
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4697<ol>
4698 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4699 <tt>false</tt> otherwise. No sign interpretation is necessary or
4700 performed.</li>
4701
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4702 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4703 <tt>false</tt> otherwise. No sign interpretation is necessary or
4704 performed.</li>
4705
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4706 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4707 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4708
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4709 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4710 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4711 to <tt>op2</tt>.</li>
4712
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4713 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4714 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4715
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4716 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4717 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4718
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4719 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4720 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4721
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4722 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4723 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4724 to <tt>op2</tt>.</li>
4725
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4726 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4727 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4728
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4729 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4730 <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]4731</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4732
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4733<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4734 values are compared as if they were integers.</p>
4735
4736<p>If the operands are integer vectors, then they are compared element by
4737 element. The result is an <tt>i1</tt> vector with the same number of elements
4738 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4739
4740<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4741<pre>
4742 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4743 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4744 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4745 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4746 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4747 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4748</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4749
4750<p>Note that the code generator does not yet support vector types with
4751 the <tt>icmp</tt> instruction.</p>
4752
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4753</div>
4754
4755<!-- _______________________________________________________________________ -->
4756<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4757</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4758
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4759<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4760
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4761<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4762<pre>
4763 &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]4764</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4765
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4766<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4767<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4768 values based on comparison of its operands.</p>
4769
4770<p>If the operands are floating point scalars, then the result type is a boolean
4771(<a href="#t_primitive"><tt>i1</tt></a>).</p>
4772
4773<p>If the operands are floating point vectors, then the result type is a vector
4774 of boolean with the same number of elements as the operands being
4775 compared.</p>
4776
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4777<h5>Arguments:</h5>
4778<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4779 the condition code indicating the kind of comparison to perform. It is not a
4780 value, just a keyword. The possible condition code are:</p>
4781
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4782<ol>
4783 <li><tt>false</tt>: no comparison, always returns false</li>
4784 <li><tt>oeq</tt>: ordered and equal</li>
4785 <li><tt>ogt</tt>: ordered and greater than </li>
4786 <li><tt>oge</tt>: ordered and greater than or equal</li>
4787 <li><tt>olt</tt>: ordered and less than </li>
4788 <li><tt>ole</tt>: ordered and less than or equal</li>
4789 <li><tt>one</tt>: ordered and not equal</li>
4790 <li><tt>ord</tt>: ordered (no nans)</li>
4791 <li><tt>ueq</tt>: unordered or equal</li>
4792 <li><tt>ugt</tt>: unordered or greater than </li>
4793 <li><tt>uge</tt>: unordered or greater than or equal</li>
4794 <li><tt>ult</tt>: unordered or less than </li>
4795 <li><tt>ule</tt>: unordered or less than or equal</li>
4796 <li><tt>une</tt>: unordered or not equal</li>
4797 <li><tt>uno</tt>: unordered (either nans)</li>
4798 <li><tt>true</tt>: no comparison, always returns true</li>
4799</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4800
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4801<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4802 <i>unordered</i> means that either operand may be a QNAN.</p>
4803
4804<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4805 a <a href="#t_floating">floating point</a> type or
4806 a <a href="#t_vector">vector</a> of floating point type. They must have
4807 identical types.</p>
4808
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4809<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4810<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4811 according to the condition code given as <tt>cond</tt>. If the operands are
4812 vectors, then the vectors are compared element by element. Each comparison
4813 performed always yields an <a href="#t_primitive">i1</a> result, as
4814 follows:</p>
4815
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4816<ol>
4817 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4818
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4819 <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]4820 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4821
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4822 <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]4823 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4824
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4825 <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]4826 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4827
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4828 <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]4829 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4830
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4831 <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]4832 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4833
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4834 <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]4835 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4836
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4837 <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]4838
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4839 <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]4840 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4841
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4842 <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]4843 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4844
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4845 <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]4846 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4847
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4848 <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]4849 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4850
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4851 <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]4852 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4853
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4854 <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]4855 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4856
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4857 <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]4858
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4859 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4860</ol>
4861
4862<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4863<pre>
4864 &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]4865 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4866 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4867 &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]4868</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4869
4870<p>Note that the code generator does not yet support vector types with
4871 the <tt>fcmp</tt> instruction.</p>
4872
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4873</div>
4874
4875<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4876<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4877 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4878</div>
4879
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4880<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4881
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4882<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4883<pre>
4884 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4885</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4886
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4887<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4888<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4889 SSA graph representing the function.</p>
4890
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4891<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4892<p>The type of the incoming values is specified with the first type field. After
4893 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4894 one pair for each predecessor basic block of the current block. Only values
4895 of <a href="#t_firstclass">first class</a> type may be used as the value
4896 arguments to the PHI node. Only labels may be used as the label
4897 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4898
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4899<p>There must be no non-phi instructions between the start of a basic block and
4900 the PHI instructions: i.e. PHI instructions must be first in a basic
4901 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4902
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4903<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4904 occur on the edge from the corresponding predecessor block to the current
4905 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4906 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4907
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4908<h5>Semantics:</h5>
4909<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4910 specified by the pair corresponding to the predecessor basic block that
4911 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4912
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4913<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4914<pre>
4915Loop: ; Infinite loop that counts from 0 on up...
4916 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4917 %nextindvar = add i32 %indvar, 1
4918 br label %Loop
4919</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4920
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4921</div>
4922
4923<!-- _______________________________________________________________________ -->
4924<div class="doc_subsubsection">
4925 <a name="i_select">'<tt>select</tt>' Instruction</a>
4926</div>
4927
4928<div class="doc_text">
4929
4930<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4931<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4932 &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>
4933
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4934 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4935</pre>
4936
4937<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4938<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4939 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4940
4941
4942<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4943<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4944 values indicating the condition, and two values of the
4945 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4946 vectors and the condition is a scalar, then entire vectors are selected, not
4947 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4948
4949<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4950<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4951 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4952
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4953<p>If the condition is a vector of i1, then the value arguments must be vectors
4954 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4955
4956<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4957<pre>
4958 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4959</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4960
4961<p>Note that the code generator does not yet support conditions
4962 with vector type.</p>
4963
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4964</div>
4965
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4966<!-- _______________________________________________________________________ -->
4967<div class="doc_subsubsection">
4968 <a name="i_call">'<tt>call</tt>' Instruction</a>
4969</div>
4970
4971<div class="doc_text">
4972
4973<h5>Syntax:</h5>
4974<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4975 &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]4976</pre>
4977
4978<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4979<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4980
4981<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4982<p>This instruction requires several arguments:</p>
4983
4984<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4985 <li>The optional "tail" marker indicates whether the callee function accesses
4986 any allocas or varargs in the caller. If the "tail" marker is present,
4987 the function call is eligible for tail call optimization. Note that calls
4988 may be marked "tail" even if they do not occur before
4989 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4990
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4991 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4992 convention</a> the call should use. If none is specified, the call
4993 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4994
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4995 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4996 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4997 '<tt>inreg</tt>' attributes are valid here.</li>
4998
4999 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5000 type of the return value. Functions that return no value are marked
5001 <tt><a href="#t_void">void</a></tt>.</li>
5002
5003 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5004 being invoked. The argument types must match the types implied by this
5005 signature. This type can be omitted if the function is not varargs and if
5006 the function type does not return a pointer to a function.</li>
5007
5008 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5009 be invoked. In most cases, this is a direct function invocation, but
5010 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5011 to function value.</li>
5012
5013 <li>'<tt>function args</tt>': argument list whose types match the function
5014 signature argument types. All arguments must be of
5015 <a href="#t_firstclass">first class</a> type. If the function signature
5016 indicates the function accepts a variable number of arguments, the extra
5017 arguments can be specified.</li>
5018
5019 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5020 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5021 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5022</ol>
5023
5024<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5025<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5026 a specified function, with its incoming arguments bound to the specified
5027 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5028 function, control flow continues with the instruction after the function
5029 call, and the return value of the function is bound to the result
5030 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5031
5032<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5033<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5034 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5035 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5036 %X = tail call i32 @foo() <i>; yields i32</i>
5037 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5038 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5039
5040 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5041 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5042 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5043 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5044 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5045 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5046</pre>
5047
5048</div>
5049
5050<!-- _______________________________________________________________________ -->
5051<div class="doc_subsubsection">
5052 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5053</div>
5054
5055<div class="doc_text">
5056
5057<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5058<pre>
5059 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5060</pre>
5061
5062<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5063<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5064 the "variable argument" area of a function call. It is used to implement the
5065 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5066
5067<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5068<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5069 argument. It returns a value of the specified argument type and increments
5070 the <tt>va_list</tt> to point to the next argument. The actual type
5071 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5072
5073<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5074<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5075 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5076 to the next argument. For more information, see the variable argument
5077 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5078
5079<p>It is legal for this instruction to be called in a function which does not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5080 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5081 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5082
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5083<p><tt>va_arg</tt> is an LLVM instruction instead of
5084 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5085 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5086
5087<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5088<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5089
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5090<p>Note that the code generator does not yet fully support va_arg on many
5091 targets. Also, it does not currently support va_arg with aggregate types on
5092 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5093
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5094</div>
5095
5096<!-- *********************************************************************** -->
5097<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5098<!-- *********************************************************************** -->
5099
5100<div class="doc_text">
5101
5102<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5103 well known names and semantics and are required to follow certain
5104 restrictions. Overall, these intrinsics represent an extension mechanism for
5105 the LLVM language that does not require changing all of the transformations
5106 in LLVM when adding to the language (or the bitcode reader/writer, the
5107 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5108
5109<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5110 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5111 begin with this prefix. Intrinsic functions must always be external
5112 functions: you cannot define the body of intrinsic functions. Intrinsic
5113 functions may only be used in call or invoke instructions: it is illegal to
5114 take the address of an intrinsic function. Additionally, because intrinsic
5115 functions are part of the LLVM language, it is required if any are added that
5116 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5117
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5118<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5119 family of functions that perform the same operation but on different data
5120 types. Because LLVM can represent over 8 million different integer types,
5121 overloading is used commonly to allow an intrinsic function to operate on any
5122 integer type. One or more of the argument types or the result type can be
5123 overloaded to accept any integer type. Argument types may also be defined as
5124 exactly matching a previous argument's type or the result type. This allows
5125 an intrinsic function which accepts multiple arguments, but needs all of them
5126 to be of the same type, to only be overloaded with respect to a single
5127 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5128
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5129<p>Overloaded intrinsics will have the names of its overloaded argument types
5130 encoded into its function name, each preceded by a period. Only those types
5131 which are overloaded result in a name suffix. Arguments whose type is matched
5132 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5133 can take an integer of any width and returns an integer of exactly the same
5134 integer width. This leads to a family of functions such as
5135 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5136 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5137 suffix is required. Because the argument's type is matched against the return
5138 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5139
5140<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5141 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5142
5143</div>
5144
5145<!-- ======================================================================= -->
5146<div class="doc_subsection">
5147 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5148</div>
5149
5150<div class="doc_text">
5151
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5152<p>Variable argument support is defined in LLVM with
5153 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5154 intrinsic functions. These functions are related to the similarly named
5155 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5156
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5157<p>All of these functions operate on arguments that use a target-specific value
5158 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5159 not define what this type is, so all transformations should be prepared to
5160 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5161
5162<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5163 instruction and the variable argument handling intrinsic functions are
5164 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5165
5166<div class="doc_code">
5167<pre>
5168define i32 @test(i32 %X, ...) {
5169 ; Initialize variable argument processing
5170 %ap = alloca i8*
5171 %ap2 = bitcast i8** %ap to i8*
5172 call void @llvm.va_start(i8* %ap2)
5173
5174 ; Read a single integer argument
5175 %tmp = va_arg i8** %ap, i32
5176
5177 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5178 %aq = alloca i8*
5179 %aq2 = bitcast i8** %aq to i8*
5180 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5181 call void @llvm.va_end(i8* %aq2)
5182
5183 ; Stop processing of arguments.
5184 call void @llvm.va_end(i8* %ap2)
5185 ret i32 %tmp
5186}
5187
5188declare void @llvm.va_start(i8*)
5189declare void @llvm.va_copy(i8*, i8*)
5190declare void @llvm.va_end(i8*)
5191</pre>
5192</div>
5193
5194</div>
5195
5196<!-- _______________________________________________________________________ -->
5197<div class="doc_subsubsection">
5198 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5199</div>
5200
5201
5202<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5203
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5204<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5205<pre>
5206 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5207</pre>
5208
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5209<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5210<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5211 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5212
5213<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5214<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5215
5216<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5217<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5218 macro available in C. In a target-dependent way, it initializes
5219 the <tt>va_list</tt> element to which the argument points, so that the next
5220 call to <tt>va_arg</tt> will produce the first variable argument passed to
5221 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5222 need to know the last argument of the function as the compiler can figure
5223 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5224
5225</div>
5226
5227<!-- _______________________________________________________________________ -->
5228<div class="doc_subsubsection">
5229 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5230</div>
5231
5232<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5233
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5234<h5>Syntax:</h5>
5235<pre>
5236 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5237</pre>
5238
5239<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5240<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5241 which has been initialized previously
5242 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5243 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5244
5245<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5246<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5247
5248<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5249<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5250 macro available in C. In a target-dependent way, it destroys
5251 the <tt>va_list</tt> element to which the argument points. Calls
5252 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5253 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5254 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5255
5256</div>
5257
5258<!-- _______________________________________________________________________ -->
5259<div class="doc_subsubsection">
5260 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5261</div>
5262
5263<div class="doc_text">
5264
5265<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5266<pre>
5267 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5268</pre>
5269
5270<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5271<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5272 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5273
5274<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5275<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5276 The second argument is a pointer to a <tt>va_list</tt> element to copy
5277 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5278
5279<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5280<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5281 macro available in C. In a target-dependent way, it copies the
5282 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5283 element. This intrinsic is necessary because
5284 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5285 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5286
5287</div>
5288
5289<!-- ======================================================================= -->
5290<div class="doc_subsection">
5291 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5292</div>
5293
5294<div class="doc_text">
5295
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5296<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5297Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5298intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5299roots on the stack</a>, as well as garbage collector implementations that
5300require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5301barriers. Front-ends for type-safe garbage collected languages should generate
5302these intrinsics to make use of the LLVM garbage collectors. For more details,
5303see <a href="GarbageCollection.html">Accurate Garbage Collection with
5304LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5305
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5306<p>The garbage collection intrinsics only operate on objects in the generic
5307 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5308
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5309</div>
5310
5311<!-- _______________________________________________________________________ -->
5312<div class="doc_subsubsection">
5313 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5314</div>
5315
5316<div class="doc_text">
5317
5318<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5319<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5320 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5321</pre>
5322
5323<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5324<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5325 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5326
5327<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5328<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5329 root pointer. The second pointer (which must be either a constant or a
5330 global value address) contains the meta-data to be associated with the
5331 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5332
5333<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5334<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5335 location. At compile-time, the code generator generates information to allow
5336 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5337 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5338 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5339
5340</div>
5341
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5342<!-- _______________________________________________________________________ -->
5343<div class="doc_subsubsection">
5344 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5345</div>
5346
5347<div class="doc_text">
5348
5349<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5350<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5351 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5352</pre>
5353
5354<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5355<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5356 locations, allowing garbage collector implementations that require read
5357 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5358
5359<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5360<p>The second argument is the address to read from, which should be an address
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5361 allocated from the garbage collector. The first object is a pointer to the
5362 start of the referenced object, if needed by the language runtime (otherwise
5363 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5364
5365<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5366<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5367 instruction, but may be replaced with substantially more complex code by the
5368 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5369 may only be used in a function which <a href="#gc">specifies a GC
5370 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5371
5372</div>
5373
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5374<!-- _______________________________________________________________________ -->
5375<div class="doc_subsubsection">
5376 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5377</div>
5378
5379<div class="doc_text">
5380
5381<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5382<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5383 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5384</pre>
5385
5386<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5387<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5388 locations, allowing garbage collector implementations that require write
5389 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5390
5391<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5392<p>The first argument is the reference to store, the second is the start of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5393 object to store it to, and the third is the address of the field of Obj to
5394 store to. If the runtime does not require a pointer to the object, Obj may
5395 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5396
5397<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5398<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5399 instruction, but may be replaced with substantially more complex code by the
5400 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5401 may only be used in a function which <a href="#gc">specifies a GC
5402 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5403
5404</div>
5405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5406<!-- ======================================================================= -->
5407<div class="doc_subsection">
5408 <a name="int_codegen">Code Generator Intrinsics</a>
5409</div>
5410
5411<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5412
5413<p>These intrinsics are provided by LLVM to expose special features that may
5414 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5415
5416</div>
5417
5418<!-- _______________________________________________________________________ -->
5419<div class="doc_subsubsection">
5420 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5421</div>
5422
5423<div class="doc_text">
5424
5425<h5>Syntax:</h5>
5426<pre>
5427 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5428</pre>
5429
5430<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5431<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5432 target-specific value indicating the return address of the current function
5433 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5434
5435<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5436<p>The argument to this intrinsic indicates which function to return the address
5437 for. Zero indicates the calling function, one indicates its caller, etc.
5438 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5439
5440<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5441<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5442 indicating the return address of the specified call frame, or zero if it
5443 cannot be identified. The value returned by this intrinsic is likely to be
5444 incorrect or 0 for arguments other than zero, so it should only be used for
5445 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5446
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5447<p>Note that calling this intrinsic does not prevent function inlining or other
5448 aggressive transformations, so the value returned may not be that of the
5449 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5450
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5451</div>
5452
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5453<!-- _______________________________________________________________________ -->
5454<div class="doc_subsubsection">
5455 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5456</div>
5457
5458<div class="doc_text">
5459
5460<h5>Syntax:</h5>
5461<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5462 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5463</pre>
5464
5465<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5466<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5467 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5468
5469<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5470<p>The argument to this intrinsic indicates which function to return the frame
5471 pointer for. Zero indicates the calling function, one indicates its caller,
5472 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5473
5474<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5475<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5476 indicating the frame address of the specified call frame, or zero if it
5477 cannot be identified. The value returned by this intrinsic is likely to be
5478 incorrect or 0 for arguments other than zero, so it should only be used for
5479 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5480
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5481<p>Note that calling this intrinsic does not prevent function inlining or other
5482 aggressive transformations, so the value returned may not be that of the
5483 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5484
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5485</div>
5486
5487<!-- _______________________________________________________________________ -->
5488<div class="doc_subsubsection">
5489 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5490</div>
5491
5492<div class="doc_text">
5493
5494<h5>Syntax:</h5>
5495<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5496 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5497</pre>
5498
5499<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5500<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5501 of the function stack, for use
5502 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5503 useful for implementing language features like scoped automatic variable
5504 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5505
5506<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5507<p>This intrinsic returns a opaque pointer value that can be passed
5508 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5509 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5510 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5511 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5512 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5513 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5514
5515</div>
5516
5517<!-- _______________________________________________________________________ -->
5518<div class="doc_subsubsection">
5519 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5520</div>
5521
5522<div class="doc_text">
5523
5524<h5>Syntax:</h5>
5525<pre>
5526 declare void @llvm.stackrestore(i8 * %ptr)
5527</pre>
5528
5529<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5530<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5531 the function stack to the state it was in when the
5532 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5533 executed. This is useful for implementing language features like scoped
5534 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5535
5536<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5537<p>See the description
5538 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5539
5540</div>
5541
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5542<!-- _______________________________________________________________________ -->
5543<div class="doc_subsubsection">
5544 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5545</div>
5546
5547<div class="doc_text">
5548
5549<h5>Syntax:</h5>
5550<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5551 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5552</pre>
5553
5554<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5555<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5556 insert a prefetch instruction if supported; otherwise, it is a noop.
5557 Prefetches have no effect on the behavior of the program but can change its
5558 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5559
5560<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5561<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5562 specifier determining if the fetch should be for a read (0) or write (1),
5563 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5564 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5565 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5566
5567<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5568<p>This intrinsic does not modify the behavior of the program. In particular,
5569 prefetches cannot trap and do not produce a value. On targets that support
5570 this intrinsic, the prefetch can provide hints to the processor cache for
5571 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5572
5573</div>
5574
5575<!-- _______________________________________________________________________ -->
5576<div class="doc_subsubsection">
5577 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5578</div>
5579
5580<div class="doc_text">
5581
5582<h5>Syntax:</h5>
5583<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5584 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5585</pre>
5586
5587<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5588<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5589 Counter (PC) in a region of code to simulators and other tools. The method
5590 is target specific, but it is expected that the marker will use exported
5591 symbols to transmit the PC of the marker. The marker makes no guarantees
5592 that it will remain with any specific instruction after optimizations. It is
5593 possible that the presence of a marker will inhibit optimizations. The
5594 intended use is to be inserted after optimizations to allow correlations of
5595 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5596
5597<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5598<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5599
5600<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5601<p>This intrinsic does not modify the behavior of the program. Backends that do
5602 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5603
5604</div>
5605
5606<!-- _______________________________________________________________________ -->
5607<div class="doc_subsubsection">
5608 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5609</div>
5610
5611<div class="doc_text">
5612
5613<h5>Syntax:</h5>
5614<pre>
5615 declare i64 @llvm.readcyclecounter( )
5616</pre>
5617
5618<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5619<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5620 counter register (or similar low latency, high accuracy clocks) on those
5621 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5622 should map to RPCC. As the backing counters overflow quickly (on the order
5623 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5624
5625<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5626<p>When directly supported, reading the cycle counter should not modify any
5627 memory. Implementations are allowed to either return a application specific
5628 value or a system wide value. On backends without support, this is lowered
5629 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5630
5631</div>
5632
5633<!-- ======================================================================= -->
5634<div class="doc_subsection">
5635 <a name="int_libc">Standard C Library Intrinsics</a>
5636</div>
5637
5638<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5639
5640<p>LLVM provides intrinsics for a few important standard C library functions.
5641 These intrinsics allow source-language front-ends to pass information about
5642 the alignment of the pointer arguments to the code generator, providing
5643 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5644
5645</div>
5646
5647<!-- _______________________________________________________________________ -->
5648<div class="doc_subsubsection">
5649 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5650</div>
5651
5652<div class="doc_text">
5653
5654<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5655<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5656 integer bit width. Not all targets support all bit widths however.</p>
5657
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5658<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5659 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5660 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5661 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5662 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5663 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5664 i32 &lt;len&gt;, i32 &lt;align&gt;)
5665 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5666 i64 &lt;len&gt;, i32 &lt;align&gt;)
5667</pre>
5668
5669<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5670<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5671 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5672
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5673<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5674 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5675
5676<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5677<p>The first argument is a pointer to the destination, the second is a pointer
5678 to the source. The third argument is an integer argument specifying the
5679 number of bytes to copy, and the fourth argument is the alignment of the
5680 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5681
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5682<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5683 then the caller guarantees that both the source and destination pointers are
5684 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5685
5686<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5687<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5688 source location to the destination location, which are not allowed to
5689 overlap. It copies "len" bytes of memory over. If the argument is known to
5690 be aligned to some boundary, this can be specified as the fourth argument,
5691 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5692
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5693</div>
5694
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5695<!-- _______________________________________________________________________ -->
5696<div class="doc_subsubsection">
5697 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5698</div>
5699
5700<div class="doc_text">
5701
5702<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5703<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5704 width. Not all targets support all bit widths however.</p>
5705
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5706<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5707 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5708 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5709 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5710 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5711 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5712 i32 &lt;len&gt;, i32 &lt;align&gt;)
5713 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5714 i64 &lt;len&gt;, i32 &lt;align&gt;)
5715</pre>
5716
5717<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5718<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5719 source location to the destination location. It is similar to the
5720 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5721 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5722
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5723<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5724 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5725
5726<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5727<p>The first argument is a pointer to the destination, the second is a pointer
5728 to the source. The third argument is an integer argument specifying the
5729 number of bytes to copy, and the fourth argument is the alignment of the
5730 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5731
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5732<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5733 then the caller guarantees that the source and destination pointers are
5734 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5735
5736<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5737<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5738 source location to the destination location, which may overlap. It copies
5739 "len" bytes of memory over. If the argument is known to be aligned to some
5740 boundary, this can be specified as the fourth argument, otherwise it should
5741 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5742
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5743</div>
5744
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5745<!-- _______________________________________________________________________ -->
5746<div class="doc_subsubsection">
5747 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5748</div>
5749
5750<div class="doc_text">
5751
5752<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5753<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5754 width. Not all targets support all bit widths however.</p>
5755
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5756<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5757 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5758 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5759 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5760 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5761 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5762 i32 &lt;len&gt;, i32 &lt;align&gt;)
5763 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5764 i64 &lt;len&gt;, i32 &lt;align&gt;)
5765</pre>
5766
5767<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5768<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5769 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5770
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5771<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5772 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5773
5774<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5775<p>The first argument is a pointer to the destination to fill, the second is the
5776 byte value to fill it with, the third argument is an integer argument
5777 specifying the number of bytes to fill, and the fourth argument is the known
5778 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5779
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5780<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5781 then the caller guarantees that the destination pointer is aligned to that
5782 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5783
5784<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5785<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5786 at the destination location. If the argument is known to be aligned to some
5787 boundary, this can be specified as the fourth argument, otherwise it should
5788 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5789
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5790</div>
5791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5792<!-- _______________________________________________________________________ -->
5793<div class="doc_subsubsection">
5794 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5795</div>
5796
5797<div class="doc_text">
5798
5799<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5800<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5801 floating point or vector of floating point type. Not all targets support all
5802 types however.</p>
5803
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5804<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5805 declare float @llvm.sqrt.f32(float %Val)
5806 declare double @llvm.sqrt.f64(double %Val)
5807 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5808 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5809 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5810</pre>
5811
5812<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5813<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5814 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5815 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5816 behavior for negative numbers other than -0.0 (which allows for better
5817 optimization, because there is no need to worry about errno being
5818 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5819
5820<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5821<p>The argument and return value are floating point numbers of the same
5822 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5823
5824<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5825<p>This function returns the sqrt of the specified operand if it is a
5826 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5827
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5828</div>
5829
5830<!-- _______________________________________________________________________ -->
5831<div class="doc_subsubsection">
5832 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5833</div>
5834
5835<div class="doc_text">
5836
5837<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5838<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5839 floating point or vector of floating point type. Not all targets support all
5840 types however.</p>
5841
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5842<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5843 declare float @llvm.powi.f32(float %Val, i32 %power)
5844 declare double @llvm.powi.f64(double %Val, i32 %power)
5845 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5846 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5847 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5848</pre>
5849
5850<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5851<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5852 specified (positive or negative) power. The order of evaluation of
5853 multiplications is not defined. When a vector of floating point type is
5854 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5855
5856<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5857<p>The second argument is an integer power, and the first is a value to raise to
5858 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5859
5860<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5861<p>This function returns the first value raised to the second power with an
5862 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5863
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5864</div>
5865
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5866<!-- _______________________________________________________________________ -->
5867<div class="doc_subsubsection">
5868 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5869</div>
5870
5871<div class="doc_text">
5872
5873<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5874<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5875 floating point or vector of floating point type. Not all targets support all
5876 types however.</p>
5877
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5878<pre>
5879 declare float @llvm.sin.f32(float %Val)
5880 declare double @llvm.sin.f64(double %Val)
5881 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5882 declare fp128 @llvm.sin.f128(fp128 %Val)
5883 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5884</pre>
5885
5886<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5887<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5888
5889<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5890<p>The argument and return value are floating point numbers of the same
5891 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5892
5893<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5894<p>This function returns the sine of the specified operand, returning the same
5895 values as the libm <tt>sin</tt> functions would, and handles error conditions
5896 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5897
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5898</div>
5899
5900<!-- _______________________________________________________________________ -->
5901<div class="doc_subsubsection">
5902 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5903</div>
5904
5905<div class="doc_text">
5906
5907<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5908<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5909 floating point or vector of floating point type. Not all targets support all
5910 types however.</p>
5911
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5912<pre>
5913 declare float @llvm.cos.f32(float %Val)
5914 declare double @llvm.cos.f64(double %Val)
5915 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5916 declare fp128 @llvm.cos.f128(fp128 %Val)
5917 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5918</pre>
5919
5920<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5921<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5922
5923<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5924<p>The argument and return value are floating point numbers of the same
5925 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5926
5927<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5928<p>This function returns the cosine of the specified operand, returning the same
5929 values as the libm <tt>cos</tt> functions would, and handles error conditions
5930 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5931
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5932</div>
5933
5934<!-- _______________________________________________________________________ -->
5935<div class="doc_subsubsection">
5936 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5937</div>
5938
5939<div class="doc_text">
5940
5941<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5942<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5943 floating point or vector of floating point type. Not all targets support all
5944 types however.</p>
5945
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5946<pre>
5947 declare float @llvm.pow.f32(float %Val, float %Power)
5948 declare double @llvm.pow.f64(double %Val, double %Power)
5949 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5950 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5951 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5952</pre>
5953
5954<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5955<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5956 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5957
5958<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5959<p>The second argument is a floating point power, and the first is a value to
5960 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5961
5962<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5963<p>This function returns the first value raised to the second power, returning
5964 the same values as the libm <tt>pow</tt> functions would, and handles error
5965 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5966
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5967</div>
5968
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5969<!-- ======================================================================= -->
5970<div class="doc_subsection">
5971 <a name="int_manip">Bit Manipulation Intrinsics</a>
5972</div>
5973
5974<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5975
5976<p>LLVM provides intrinsics for a few important bit manipulation operations.
5977 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5978
5979</div>
5980
5981<!-- _______________________________________________________________________ -->
5982<div class="doc_subsubsection">
5983 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5984</div>
5985
5986<div class="doc_text">
5987
5988<h5>Syntax:</h5>
5989<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5990 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5991
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5992<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5993 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5994 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5995 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5996</pre>
5997
5998<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5999<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6000 values with an even number of bytes (positive multiple of 16 bits). These
6001 are useful for performing operations on data that is not in the target's
6002 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6003
6004<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6005<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6006 and low byte of the input i16 swapped. Similarly,
6007 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6008 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6009 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6010 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6011 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6012 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6013
6014</div>
6015
6016<!-- _______________________________________________________________________ -->
6017<div class="doc_subsubsection">
6018 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6019</div>
6020
6021<div class="doc_text">
6022
6023<h5>Syntax:</h5>
6024<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6025 width. Not all targets support all bit widths however.</p>
6026
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6027<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6028 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6029 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6030 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6031 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6032 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6033</pre>
6034
6035<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6036<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6037 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6038
6039<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6040<p>The only argument is the value to be counted. The argument may be of any
6041 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6042
6043<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6044<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6045
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6046</div>
6047
6048<!-- _______________________________________________________________________ -->
6049<div class="doc_subsubsection">
6050 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6051</div>
6052
6053<div class="doc_text">
6054
6055<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6056<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6057 integer bit width. Not all targets support all bit widths however.</p>
6058
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6059<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6060 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6061 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6062 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6063 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6064 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6065</pre>
6066
6067<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6068<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6069 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6070
6071<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6072<p>The only argument is the value to be counted. The argument may be of any
6073 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6074
6075<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6076<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6077 zeros in a variable. If the src == 0 then the result is the size in bits of
6078 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6079
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6080</div>
6081
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6082<!-- _______________________________________________________________________ -->
6083<div class="doc_subsubsection">
6084 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6085</div>
6086
6087<div class="doc_text">
6088
6089<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6090<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6091 integer bit width. Not all targets support all bit widths however.</p>
6092
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6093<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6094 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6095 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6096 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6097 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6098 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6099</pre>
6100
6101<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6102<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6103 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6104
6105<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6106<p>The only argument is the value to be counted. The argument may be of any
6107 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6108
6109<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6110<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6111 zeros in a variable. If the src == 0 then the result is the size in bits of
6112 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6113
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6114</div>
6115
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6116<!-- ======================================================================= -->
6117<div class="doc_subsection">
6118 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6119</div>
6120
6121<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6122
6123<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6124
6125</div>
6126
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6127<!-- _______________________________________________________________________ -->
6128<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6129 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6130</div>
6131
6132<div class="doc_text">
6133
6134<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6135<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6136 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6137
6138<pre>
6139 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6140 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6141 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6142</pre>
6143
6144<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6145<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6146 a signed addition of the two arguments, and indicate whether an overflow
6147 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6148
6149<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6150<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6151 be of integer types of any bit width, but they must have the same bit
6152 width. The second element of the result structure must be of
6153 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6154 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6155
6156<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6157<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6158 a signed addition of the two variables. They return a structure &mdash; the
6159 first element of which is the signed summation, and the second element of
6160 which is a bit specifying if the signed summation resulted in an
6161 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6162
6163<h5>Examples:</h5>
6164<pre>
6165 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6166 %sum = extractvalue {i32, i1} %res, 0
6167 %obit = extractvalue {i32, i1} %res, 1
6168 br i1 %obit, label %overflow, label %normal
6169</pre>
6170
6171</div>
6172
6173<!-- _______________________________________________________________________ -->
6174<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6175 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6176</div>
6177
6178<div class="doc_text">
6179
6180<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6181<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6182 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6183
6184<pre>
6185 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6186 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6187 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6188</pre>
6189
6190<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6191<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6192 an unsigned addition of the two arguments, and indicate whether a carry
6193 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6194
6195<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6196<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6197 be of integer types of any bit width, but they must have the same bit
6198 width. The second element of the result structure must be of
6199 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6200 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6201
6202<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6203<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6204 an unsigned addition of the two arguments. They return a structure &mdash;
6205 the first element of which is the sum, and the second element of which is a
6206 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6207
6208<h5>Examples:</h5>
6209<pre>
6210 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6211 %sum = extractvalue {i32, i1} %res, 0
6212 %obit = extractvalue {i32, i1} %res, 1
6213 br i1 %obit, label %carry, label %normal
6214</pre>
6215
6216</div>
6217
6218<!-- _______________________________________________________________________ -->
6219<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6220 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6221</div>
6222
6223<div class="doc_text">
6224
6225<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6226<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6227 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6228
6229<pre>
6230 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6231 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6232 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6233</pre>
6234
6235<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6236<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6237 a signed subtraction of the two arguments, and indicate whether an overflow
6238 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6239
6240<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6241<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6242 be of integer types of any bit width, but they must have the same bit
6243 width. The second element of the result structure must be of
6244 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6245 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6246
6247<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6248<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6249 a signed subtraction of the two arguments. They return a structure &mdash;
6250 the first element of which is the subtraction, and the second element of
6251 which is a bit specifying if the signed subtraction resulted in an
6252 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6253
6254<h5>Examples:</h5>
6255<pre>
6256 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6257 %sum = extractvalue {i32, i1} %res, 0
6258 %obit = extractvalue {i32, i1} %res, 1
6259 br i1 %obit, label %overflow, label %normal
6260</pre>
6261
6262</div>
6263
6264<!-- _______________________________________________________________________ -->
6265<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6266 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6267</div>
6268
6269<div class="doc_text">
6270
6271<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6272<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6273 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6274
6275<pre>
6276 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6277 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6278 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6279</pre>
6280
6281<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6282<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6283 an unsigned subtraction of the two arguments, and indicate whether an
6284 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6285
6286<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6287<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6288 be of integer types of any bit width, but they must have the same bit
6289 width. The second element of the result structure must be of
6290 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6291 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6292
6293<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6294<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6295 an unsigned subtraction of the two arguments. They return a structure &mdash;
6296 the first element of which is the subtraction, and the second element of
6297 which is a bit specifying if the unsigned subtraction resulted in an
6298 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6299
6300<h5>Examples:</h5>
6301<pre>
6302 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6303 %sum = extractvalue {i32, i1} %res, 0
6304 %obit = extractvalue {i32, i1} %res, 1
6305 br i1 %obit, label %overflow, label %normal
6306</pre>
6307
6308</div>
6309
6310<!-- _______________________________________________________________________ -->
6311<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6312 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6313</div>
6314
6315<div class="doc_text">
6316
6317<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6318<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6319 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6320
6321<pre>
6322 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6323 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6324 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6325</pre>
6326
6327<h5>Overview:</h5>
6328
6329<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6330 a signed multiplication of the two arguments, and indicate whether an
6331 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6332
6333<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6334<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6335 be of integer types of any bit width, but they must have the same bit
6336 width. The second element of the result structure must be of
6337 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6338 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6339
6340<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6341<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6342 a signed multiplication of the two arguments. They return a structure &mdash;
6343 the first element of which is the multiplication, and the second element of
6344 which is a bit specifying if the signed multiplication resulted in an
6345 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6346
6347<h5>Examples:</h5>
6348<pre>
6349 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6350 %sum = extractvalue {i32, i1} %res, 0
6351 %obit = extractvalue {i32, i1} %res, 1
6352 br i1 %obit, label %overflow, label %normal
6353</pre>
6354
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6355</div>
6356
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6357<!-- _______________________________________________________________________ -->
6358<div class="doc_subsubsection">
6359 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6360</div>
6361
6362<div class="doc_text">
6363
6364<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6365<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6366 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6367
6368<pre>
6369 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6370 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6371 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6372</pre>
6373
6374<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6375<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6376 a unsigned multiplication of the two arguments, and indicate whether an
6377 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6378
6379<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6380<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6381 be of integer types of any bit width, but they must have the same bit
6382 width. The second element of the result structure must be of
6383 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6384 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6385
6386<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6387<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6388 an unsigned multiplication of the two arguments. They return a structure
6389 &mdash; the first element of which is the multiplication, and the second
6390 element of which is a bit specifying if the unsigned multiplication resulted
6391 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6392
6393<h5>Examples:</h5>
6394<pre>
6395 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6396 %sum = extractvalue {i32, i1} %res, 0
6397 %obit = extractvalue {i32, i1} %res, 1
6398 br i1 %obit, label %overflow, label %normal
6399</pre>
6400
6401</div>
6402
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6403<!-- ======================================================================= -->
6404<div class="doc_subsection">
6405 <a name="int_debugger">Debugger Intrinsics</a>
6406</div>
6407
6408<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6409
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6410<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6411 prefix), are described in
6412 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6413 Level Debugging</a> document.</p>
6414
6415</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6416
6417<!-- ======================================================================= -->
6418<div class="doc_subsection">
6419 <a name="int_eh">Exception Handling Intrinsics</a>
6420</div>
6421
6422<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6423
6424<p>The LLVM exception handling intrinsics (which all start with
6425 <tt>llvm.eh.</tt> prefix), are described in
6426 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6427 Handling</a> document.</p>
6428
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6429</div>
6430
6431<!-- ======================================================================= -->
6432<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6433 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6434</div>
6435
6436<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6437
6438<p>This intrinsic makes it possible to excise one parameter, marked with
6439 the <tt>nest</tt> attribute, from a function. The result is a callable
6440 function pointer lacking the nest parameter - the caller does not need to
6441 provide a value for it. Instead, the value to use is stored in advance in a
6442 "trampoline", a block of memory usually allocated on the stack, which also
6443 contains code to splice the nest value into the argument list. This is used
6444 to implement the GCC nested function address extension.</p>
6445
6446<p>For example, if the function is
6447 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6448 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6449 follows:</p>
6450
6451<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6452<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6453 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6454 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6455 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6456 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6457</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6458</div>
6459
6460<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6461 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6462
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6463</div>
6464
6465<!-- _______________________________________________________________________ -->
6466<div class="doc_subsubsection">
6467 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6468</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6469
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6470<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6471
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6472<h5>Syntax:</h5>
6473<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6474 declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6475</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6476
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6477<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6478<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6479 function pointer suitable for executing it.</p>
6480
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6481<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6482<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6483 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6484 sufficiently aligned block of memory; this memory is written to by the
6485 intrinsic. Note that the size and the alignment are target-specific - LLVM
6486 currently provides no portable way of determining them, so a front-end that
6487 generates this intrinsic needs to have some target-specific knowledge.
6488 The <tt>func</tt> argument must hold a function bitcast to
6489 an <tt>i8*</tt>.</p>
6490
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6491<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6492<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6493 dependent code, turning it into a function. A pointer to this function is
6494 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6495 function pointer type</a> before being called. The new function's signature
6496 is the same as that of <tt>func</tt> with any arguments marked with
6497 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6498 is allowed, and it must be of pointer type. Calling the new function is
6499 equivalent to calling <tt>func</tt> with the same argument list, but
6500 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6501 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6502 by <tt>tramp</tt> is modified, then the effect of any later call to the
6503 returned function pointer is undefined.</p>
6504
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6505</div>
6506
6507<!-- ======================================================================= -->
6508<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6509 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6510</div>
6511
6512<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6513
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6514<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6515 hardware constructs for atomic operations and memory synchronization. This
6516 provides an interface to the hardware, not an interface to the programmer. It
6517 is aimed at a low enough level to allow any programming models or APIs
6518 (Application Programming Interfaces) which need atomic behaviors to map
6519 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6520 hardware provides a "universal IR" for source languages, it also provides a
6521 starting point for developing a "universal" atomic operation and
6522 synchronization IR.</p>
6523
6524<p>These do <em>not</em> form an API such as high-level threading libraries,
6525 software transaction memory systems, atomic primitives, and intrinsic
6526 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6527 application libraries. The hardware interface provided by LLVM should allow
6528 a clean implementation of all of these APIs and parallel programming models.
6529 No one model or paradigm should be selected above others unless the hardware
6530 itself ubiquitously does so.</p>
6531
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6532</div>
6533
6534<!-- _______________________________________________________________________ -->
6535<div class="doc_subsubsection">
6536 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6537</div>
6538<div class="doc_text">
6539<h5>Syntax:</h5>
6540<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6541 declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;, i1 &lt;device&gt; )
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6542</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6543
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6544<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6545<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6546 specific pairs of memory access types.</p>
6547
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6548<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6549<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6550 The first four arguments enables a specific barrier as listed below. The
6551 fith argument specifies that the barrier applies to io or device or uncached
6552 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6553
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6554<ul>
6555 <li><tt>ll</tt>: load-load barrier</li>
6556 <li><tt>ls</tt>: load-store barrier</li>
6557 <li><tt>sl</tt>: store-load barrier</li>
6558 <li><tt>ss</tt>: store-store barrier</li>
6559 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6560</ul>
6561
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6562<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6563<p>This intrinsic causes the system to enforce some ordering constraints upon
6564 the loads and stores of the program. This barrier does not
6565 indicate <em>when</em> any events will occur, it only enforces
6566 an <em>order</em> in which they occur. For any of the specified pairs of load
6567 and store operations (f.ex. load-load, or store-load), all of the first
6568 operations preceding the barrier will complete before any of the second
6569 operations succeeding the barrier begin. Specifically the semantics for each
6570 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6571
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6572<ul>
6573 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6574 after the barrier begins.</li>
6575 <li><tt>ls</tt>: All loads before the barrier must complete before any
6576 store after the barrier begins.</li>
6577 <li><tt>ss</tt>: All stores before the barrier must complete before any
6578 store after the barrier begins.</li>
6579 <li><tt>sl</tt>: All stores before the barrier must complete before any
6580 load after the barrier begins.</li>
6581</ul>
6582
6583<p>These semantics are applied with a logical "and" behavior when more than one
6584 is enabled in a single memory barrier intrinsic.</p>
6585
6586<p>Backends may implement stronger barriers than those requested when they do
6587 not support as fine grained a barrier as requested. Some architectures do
6588 not need all types of barriers and on such architectures, these become
6589 noops.</p>
6590
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6591<h5>Example:</h5>
6592<pre>
6593%ptr = malloc i32
6594 store i32 4, %ptr
6595
6596%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6597 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6598 <i>; guarantee the above finishes</i>
6599 store i32 8, %ptr <i>; before this begins</i>
6600</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6601
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6602</div>
6603
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6604<!-- _______________________________________________________________________ -->
6605<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6606 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6607</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6608
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6609<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6610
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6611<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6612<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6613 any integer bit width and for different address spaces. Not all targets
6614 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6615
6616<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6617 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6618 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6619 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6620 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]6621</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6622
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6623<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6624<p>This loads a value in memory and compares it to a given value. If they are
6625 equal, it stores a new value into the memory.</p>
6626
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6627<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6628<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6629 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6630 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6631 this integer type. While any bit width integer may be used, targets may only
6632 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6633
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6634<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6635<p>This entire intrinsic must be executed atomically. It first loads the value
6636 in memory pointed to by <tt>ptr</tt> and compares it with the
6637 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6638 memory. The loaded value is yielded in all cases. This provides the
6639 equivalent of an atomic compare-and-swap operation within the SSA
6640 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6641
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6642<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6643<pre>
6644%ptr = malloc i32
6645 store i32 4, %ptr
6646
6647%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6648%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6649 <i>; yields {i32}:result1 = 4</i>
6650%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6651%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6652
6653%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6654%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6655 <i>; yields {i32}:result2 = 8</i>
6656%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6657
6658%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6659</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6660
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6661</div>
6662
6663<!-- _______________________________________________________________________ -->
6664<div class="doc_subsubsection">
6665 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6666</div>
6667<div class="doc_text">
6668<h5>Syntax:</h5>
6669
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6670<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6671 integer bit width. Not all targets support all bit widths however.</p>
6672
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6673<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6674 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6675 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6676 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6677 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]6678</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6679
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6680<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6681<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6682 the value from memory. It then stores the value in <tt>val</tt> in the memory
6683 at <tt>ptr</tt>.</p>
6684
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6685<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6686<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6687 the <tt>val</tt> argument and the result must be integers of the same bit
6688 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6689 integer type. The targets may only lower integer representations they
6690 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6691
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6692<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6693<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6694 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6695 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6696
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6697<h5>Examples:</h5>
6698<pre>
6699%ptr = malloc i32
6700 store i32 4, %ptr
6701
6702%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6703%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6704 <i>; yields {i32}:result1 = 4</i>
6705%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6706%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6707
6708%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6709%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6710 <i>; yields {i32}:result2 = 8</i>
6711
6712%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6713%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6714</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6715
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6716</div>
6717
6718<!-- _______________________________________________________________________ -->
6719<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6720 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6721
6722</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6723
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6724<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6725
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6726<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6727<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6728 any integer bit width. Not all targets support all bit widths however.</p>
6729
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6730<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6731 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6732 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6733 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6734 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]6735</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6736
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6737<h5>Overview:</h5>
6738<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6739 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6740
6741<h5>Arguments:</h5>
6742<p>The intrinsic takes two arguments, the first a pointer to an integer value
6743 and the second an integer value. The result is also an integer value. These
6744 integer types can have any bit width, but they must all have the same bit
6745 width. The targets may only lower integer representations they support.</p>
6746
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6747<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6748<p>This intrinsic does a series of operations atomically. It first loads the
6749 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6750 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]6751
6752<h5>Examples:</h5>
6753<pre>
6754%ptr = malloc i32
6755 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6756%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6757 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6758%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6759 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6760%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6761 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6762%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6763</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6764
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6765</div>
6766
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6767<!-- _______________________________________________________________________ -->
6768<div class="doc_subsubsection">
6769 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6770
6771</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6772
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6773<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6774
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6775<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6776<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6777 any integer bit width and for different address spaces. Not all targets
6778 support all bit widths however.</p>
6779
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6780<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6781 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6782 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6783 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6784 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]6785</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6786
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6787<h5>Overview:</h5>
6788<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6789 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6790
6791<h5>Arguments:</h5>
6792<p>The intrinsic takes two arguments, the first a pointer to an integer value
6793 and the second an integer value. The result is also an integer value. These
6794 integer types can have any bit width, but they must all have the same bit
6795 width. The targets may only lower integer representations they support.</p>
6796
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6797<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6798<p>This intrinsic does a series of operations atomically. It first loads the
6799 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6800 result to <tt>ptr</tt>. It yields the original value stored
6801 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6802
6803<h5>Examples:</h5>
6804<pre>
6805%ptr = malloc i32
6806 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6807%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6808 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6809%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6810 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6811%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6812 <i>; yields {i32}:result3 = 2</i>
6813%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6814</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6815
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6816</div>
6817
6818<!-- _______________________________________________________________________ -->
6819<div class="doc_subsubsection">
6820 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6821 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6822 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6823 <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]6824</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6825
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6826<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6827
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6828<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6829<p>These are overloaded intrinsics. You can
6830 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6831 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6832 bit width and for different address spaces. Not all targets support all bit
6833 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6834
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6835<pre>
6836 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6837 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6838 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6839 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]6840</pre>
6841
6842<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6843 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6844 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6845 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6846 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]6847</pre>
6848
6849<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6850 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6851 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6852 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6853 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]6854</pre>
6855
6856<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6857 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6858 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6859 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6860 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]6861</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6862
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6863<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6864<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6865 the value stored in memory at <tt>ptr</tt>. It yields the original value
6866 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6867
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6868<h5>Arguments:</h5>
6869<p>These intrinsics take two arguments, the first a pointer to an integer value
6870 and the second an integer value. The result is also an integer value. These
6871 integer types can have any bit width, but they must all have the same bit
6872 width. The targets may only lower integer representations they support.</p>
6873
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6874<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6875<p>These intrinsics does a series of operations atomically. They first load the
6876 value stored at <tt>ptr</tt>. They then do the bitwise
6877 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6878 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6879
6880<h5>Examples:</h5>
6881<pre>
6882%ptr = malloc i32
6883 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6884%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6885 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6886%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6887 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6888%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6889 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6890%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6891 <i>; yields {i32}:result3 = FF</i>
6892%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6893</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6894
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6895</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6896
6897<!-- _______________________________________________________________________ -->
6898<div class="doc_subsubsection">
6899 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6900 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6901 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6902 <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]6903</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6904
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6905<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6906
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6907<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6908<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6909 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6910 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6911 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6912
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6913<pre>
6914 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6915 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6916 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6917 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]6918</pre>
6919
6920<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6921 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6922 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6923 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6924 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]6925</pre>
6926
6927<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6928 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6929 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6930 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6931 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]6932</pre>
6933
6934<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6935 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6936 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6937 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6938 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]6939</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6940
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6941<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6942<p>These intrinsics takes the signed or unsigned minimum or maximum of
6943 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6944 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6945
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6946<h5>Arguments:</h5>
6947<p>These intrinsics take two arguments, the first a pointer to an integer value
6948 and the second an integer value. The result is also an integer value. These
6949 integer types can have any bit width, but they must all have the same bit
6950 width. The targets may only lower integer representations they support.</p>
6951
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6952<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6953<p>These intrinsics does a series of operations atomically. They first load the
6954 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6955 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6956 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6957
6958<h5>Examples:</h5>
6959<pre>
6960%ptr = malloc i32
6961 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6962%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6963 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6964%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6965 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6966%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6967 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6968%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6969 <i>; yields {i32}:result3 = 8</i>
6970%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6971</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6972
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6973</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6974
6975<!-- ======================================================================= -->
6976<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6977 <a name="int_general">General Intrinsics</a>
6978</div>
6979
6980<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6981
6982<p>This class of intrinsics is designed to be generic and has no specific
6983 purpose.</p>
6984
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6985</div>
6986
6987<!-- _______________________________________________________________________ -->
6988<div class="doc_subsubsection">
6989 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6990</div>
6991
6992<div class="doc_text">
6993
6994<h5>Syntax:</h5>
6995<pre>
6996 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6997</pre>
6998
6999<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7000<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7001
7002<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7003<p>The first argument is a pointer to a value, the second is a pointer to a
7004 global string, the third is a pointer to a global string which is the source
7005 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7006
7007<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7008<p>This intrinsic allows annotation of local variables with arbitrary strings.
7009 This can be useful for special purpose optimizations that want to look for
7010 these annotations. These have no other defined use, they are ignored by code
7011 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7012
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7013</div>
7014
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7015<!-- _______________________________________________________________________ -->
7016<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7017 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7018</div>
7019
7020<div class="doc_text">
7021
7022<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7023<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7024 any integer bit width.</p>
7025
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7026<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7027 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7028 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7029 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7030 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7031 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]7032</pre>
7033
7034<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7035<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7036
7037<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7038<p>The first argument is an integer value (result of some expression), the
7039 second is a pointer to a global string, the third is a pointer to a global
7040 string which is the source file name, and the last argument is the line
7041 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7042
7043<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7044<p>This intrinsic allows annotations to be put on arbitrary expressions with
7045 arbitrary strings. This can be useful for special purpose optimizations that
7046 want to look for these annotations. These have no other defined use, they
7047 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7048
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7049</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7050
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7051<!-- _______________________________________________________________________ -->
7052<div class="doc_subsubsection">
7053 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7054</div>
7055
7056<div class="doc_text">
7057
7058<h5>Syntax:</h5>
7059<pre>
7060 declare void @llvm.trap()
7061</pre>
7062
7063<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7064<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7065
7066<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7067<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7068
7069<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7070<p>This intrinsics is lowered to the target dependent trap instruction. If the
7071 target does not have a trap instruction, this intrinsic will be lowered to
7072 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7073
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7074</div>
7075
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7076<!-- _______________________________________________________________________ -->
7077<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7078 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7079</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7080
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7081<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7082
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7083<h5>Syntax:</h5>
7084<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7085 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7086</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7087
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7088<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7089<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7090 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7091 ensure that it is placed on the stack before local variables.</p>
7092
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7093<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7094<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7095 arguments. The first argument is the value loaded from the stack
7096 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7097 that has enough space to hold the value of the guard.</p>
7098
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7099<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7100<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7101 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7102 stack. This is to ensure that if a local variable on the stack is
7103 overwritten, it will destroy the value of the guard. When the function exits,
7104 the guard on the stack is checked against the original guard. If they're
7105 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7106 function.</p>
7107
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7108</div>
7109
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7110<!-- *********************************************************************** -->
7111<hr>
7112<address>
7113 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7115 <a href="http://validator.w3.org/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7117
7118 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7119 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7120 Last modified: $Date$
7121</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7122
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7123</body>
7124</html>