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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 0273f182cb12b8627e629784e04b2e05d982eddd / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
27 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
28 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
29 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
30 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
31 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
32 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
33 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner0fee5c22009-10-10 18:26:06 +0000[diff] [blame]34 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]35 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
36 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
37 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]39 </ol>
40 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]41 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]42 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]43 <li><a href="#globalvars">Global Variables</a></li>
44 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]45 <li><a href="#aliasstructure">Aliases</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]46 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]47 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]48 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]49 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
50 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]51 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]52 </ol>
53 </li>
54 <li><a href="#typesystem">Type System</a>
55 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]56 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]57 <li><a href="#t_primitive">Primitive Types</a>
58 <ol>
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]59 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_floating">Floating Point Types</a></li>
61 <li><a href="#t_void">Void Type</a></li>
62 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]63 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]64 </ol>
65 </li>
66 <li><a href="#t_derived">Derived Types</a>
67 <ol>
68 <li><a href="#t_array">Array Type</a></li>
69 <li><a href="#t_function">Function Type</a></li>
70 <li><a href="#t_pointer">Pointer Type</a></li>
71 <li><a href="#t_struct">Structure Type</a></li>
72 <li><a href="#t_pstruct">Packed Structure Type</a></li>
73 <li><a href="#t_vector">Vector Type</a></li>
74 <li><a href="#t_opaque">Opaque Type</a></li>
75 </ol>
76 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]77 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]78 </ol>
79 </li>
80 <li><a href="#constants">Constants</a>
81 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]82 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]83 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]84 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
85 <li><a href="#undefvalues">Undefined Values</a></li>
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]86 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]87 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]88 <li><a href="#metadata">Embedded Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]89 </ol>
90 </li>
91 <li><a href="#othervalues">Other Values</a>
92 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]94 </ol>
95 </li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]96 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
97 <ol>
98 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]99 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
100 Global Variable</a></li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]101 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
102 Global Variable</a></li>
103 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
104 Global Variable</a></li>
105 </ol>
106 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]107 <li><a href="#instref">Instruction Reference</a>
108 <ol>
109 <li><a href="#terminators">Terminator Instructions</a>
110 <ol>
111 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
112 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
113 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]114 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]115 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
116 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
117 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
118 </ol>
119 </li>
120 <li><a href="#binaryops">Binary Operations</a>
121 <ol>
122 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]123 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]124 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]125 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]126 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]127 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]128 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
129 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
130 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
131 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
132 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
133 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
134 </ol>
135 </li>
136 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
137 <ol>
138 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
139 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
140 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
141 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
142 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
143 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
144 </ol>
145 </li>
146 <li><a href="#vectorops">Vector Operations</a>
147 <ol>
148 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
149 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
150 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
151 </ol>
152 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]153 <li><a href="#aggregateops">Aggregate Operations</a>
154 <ol>
155 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
156 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
157 </ol>
158 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]159 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
160 <ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]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>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]276 <li><a href="#int_memorymarkers">Memory Use Markers</a>
277 <ol>
278 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
279 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
280 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
281 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
282 </ol>
283 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]284 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]285 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]286 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]287 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]288 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]289 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]290 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]291 '<tt>llvm.trap</tt>' Intrinsic</a></li>
292 <li><a href="#int_stackprotector">
293 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]294 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]295 </li>
296 </ol>
297 </li>
298</ol>
299
300<div class="doc_author">
301 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
302 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
303</div>
304
305<!-- *********************************************************************** -->
306<div class="doc_section"> <a name="abstract">Abstract </a></div>
307<!-- *********************************************************************** -->
308
309<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]310
311<p>This document is a reference manual for the LLVM assembly language. LLVM is
312 a Static Single Assignment (SSA) based representation that provides type
313 safety, low-level operations, flexibility, and the capability of representing
314 'all' high-level languages cleanly. It is the common code representation
315 used throughout all phases of the LLVM compilation strategy.</p>
316
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]317</div>
318
319<!-- *********************************************************************** -->
320<div class="doc_section"> <a name="introduction">Introduction</a> </div>
321<!-- *********************************************************************** -->
322
323<div class="doc_text">
324
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]325<p>The LLVM code representation is designed to be used in three different forms:
326 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
327 for fast loading by a Just-In-Time compiler), and as a human readable
328 assembly language representation. This allows LLVM to provide a powerful
329 intermediate representation for efficient compiler transformations and
330 analysis, while providing a natural means to debug and visualize the
331 transformations. The three different forms of LLVM are all equivalent. This
332 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]333
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]334<p>The LLVM representation aims to be light-weight and low-level while being
335 expressive, typed, and extensible at the same time. It aims to be a
336 "universal IR" of sorts, by being at a low enough level that high-level ideas
337 may be cleanly mapped to it (similar to how microprocessors are "universal
338 IR's", allowing many source languages to be mapped to them). By providing
339 type information, LLVM can be used as the target of optimizations: for
340 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]341 variable is never accessed outside of the current function, allowing it to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]342 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]343
344</div>
345
346<!-- _______________________________________________________________________ -->
347<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
348
349<div class="doc_text">
350
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]351<p>It is important to note that this document describes 'well formed' LLVM
352 assembly language. There is a difference between what the parser accepts and
353 what is considered 'well formed'. For example, the following instruction is
354 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]355
356<div class="doc_code">
357<pre>
358%x = <a href="#i_add">add</a> i32 1, %x
359</pre>
360</div>
361
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]362<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
363 LLVM infrastructure provides a verification pass that may be used to verify
364 that an LLVM module is well formed. This pass is automatically run by the
365 parser after parsing input assembly and by the optimizer before it outputs
366 bitcode. The violations pointed out by the verifier pass indicate bugs in
367 transformation passes or input to the parser.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]368
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]369</div>
370
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]371<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]372
373<!-- *********************************************************************** -->
374<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
375<!-- *********************************************************************** -->
376
377<div class="doc_text">
378
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]379<p>LLVM identifiers come in two basic types: global and local. Global
380 identifiers (functions, global variables) begin with the <tt>'@'</tt>
381 character. Local identifiers (register names, types) begin with
382 the <tt>'%'</tt> character. Additionally, there are three different formats
383 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]384
385<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]386 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]387 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
388 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
389 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
390 other characters in their names can be surrounded with quotes. Special
391 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
392 ASCII code for the character in hexadecimal. In this way, any character
393 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]394
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]395 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]396 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]397
398 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]399 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]400</ol>
401
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]402<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]403 don't need to worry about name clashes with reserved words, and the set of
404 reserved words may be expanded in the future without penalty. Additionally,
405 unnamed identifiers allow a compiler to quickly come up with a temporary
406 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]407
408<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]409 languages. There are keywords for different opcodes
410 ('<tt><a href="#i_add">add</a></tt>',
411 '<tt><a href="#i_bitcast">bitcast</a></tt>',
412 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
413 ('<tt><a href="#t_void">void</a></tt>',
414 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
415 reserved words cannot conflict with variable names, because none of them
416 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]417
418<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]419 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]420
421<p>The easy way:</p>
422
423<div class="doc_code">
424<pre>
425%result = <a href="#i_mul">mul</a> i32 %X, 8
426</pre>
427</div>
428
429<p>After strength reduction:</p>
430
431<div class="doc_code">
432<pre>
433%result = <a href="#i_shl">shl</a> i32 %X, i8 3
434</pre>
435</div>
436
437<p>And the hard way:</p>
438
439<div class="doc_code">
440<pre>
Gabor Greifc0ea7672009-10-28 13:05:07 +0000[diff] [blame]441%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
442%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]443%result = <a href="#i_add">add</a> i32 %1, %1
444</pre>
445</div>
446
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]447<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
448 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]449
450<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]451 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]452 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]453
454 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]455 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]456
457 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]458</ol>
459
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]460<p>It also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]461 demonstrating instructions, we will follow an instruction with a comment that
462 defines the type and name of value produced. Comments are shown in italic
463 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]464
465</div>
466
467<!-- *********************************************************************** -->
468<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
469<!-- *********************************************************************** -->
470
471<!-- ======================================================================= -->
472<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
473</div>
474
475<div class="doc_text">
476
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]477<p>LLVM programs are composed of "Module"s, each of which is a translation unit
478 of the input programs. Each module consists of functions, global variables,
479 and symbol table entries. Modules may be combined together with the LLVM
480 linker, which merges function (and global variable) definitions, resolves
481 forward declarations, and merges symbol table entries. Here is an example of
482 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]483
484<div class="doc_code">
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]485<pre>
486<i>; Declare the string constant as a global constant.</i>
487<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]488
489<i>; External declaration of the puts function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]490<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]491
492<i>; Definition of main function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]493define i32 @main() { <i>; i32()* </i>
494 <i>; Convert [13 x i8]* to i8 *...</i>
495 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]496
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]497 <i>; Call puts function to write out the string to stdout.</i>
498 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
499 <a href="#i_ret">ret</a> i32 0<br>}<br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]500</pre>
501</div>
502
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]503<p>This example is made up of a <a href="#globalvars">global variable</a> named
504 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
505 a <a href="#functionstructure">function definition</a> for
506 "<tt>main</tt>".</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]507
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]508<p>In general, a module is made up of a list of global values, where both
509 functions and global variables are global values. Global values are
510 represented by a pointer to a memory location (in this case, a pointer to an
511 array of char, and a pointer to a function), and have one of the
512 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]513
514</div>
515
516<!-- ======================================================================= -->
517<div class="doc_subsection">
518 <a name="linkage">Linkage Types</a>
519</div>
520
521<div class="doc_text">
522
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]523<p>All Global Variables and Functions have one of the following types of
524 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]525
526<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]527 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]528 <dd>Global values with private linkage are only directly accessible by objects
529 in the current module. In particular, linking code into a module with an
530 private global value may cause the private to be renamed as necessary to
531 avoid collisions. Because the symbol is private to the module, all
532 references can be updated. This doesn't show up in any symbol table in the
533 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]534
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]535 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]536 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattner06c1ecc2009-08-24 04:32:16 +0000[diff] [blame]537 removed by the linker after evaluation. Note that (unlike private
538 symbols) linker_private symbols are subject to coalescing by the linker:
539 weak symbols get merged and redefinitions are rejected. However, unlike
540 normal strong symbols, they are removed by the linker from the final
541 linked image (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]542
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]544 <dd>Similar to private, but the value shows as a local symbol
545 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
546 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]547
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]549 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]550 into the object file corresponding to the LLVM module. They exist to
551 allow inlining and other optimizations to take place given knowledge of
552 the definition of the global, which is known to be somewhere outside the
553 module. Globals with <tt>available_externally</tt> linkage are allowed to
554 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
555 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]556
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]557 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]558 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]559 the same name when linkage occurs. This is typically used to implement
560 inline functions, templates, or other code which must be generated in each
561 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
562 allowed to be discarded.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]563
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]564 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]565 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
566 <tt>linkonce</tt> linkage, except that unreferenced globals with
567 <tt>weak</tt> linkage may not be discarded. This is used for globals that
568 are declared "weak" in C source code.</dd>
569
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]571 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
572 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
573 global scope.
574 Symbols with "<tt>common</tt>" linkage are merged in the same way as
575 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]576 <tt>common</tt> symbols may not have an explicit section,
577 must have a zero initializer, and may not be marked '<a
578 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
579 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]580
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]581
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]582 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]583 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]584 pointer to array type. When two global variables with appending linkage
585 are linked together, the two global arrays are appended together. This is
586 the LLVM, typesafe, equivalent of having the system linker append together
587 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]588
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]589 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]590 <dd>The semantics of this linkage follow the ELF object file model: the symbol
591 is weak until linked, if not linked, the symbol becomes null instead of
592 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]593
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]594 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
595 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]596 <dd>Some languages allow differing globals to be merged, such as two functions
597 with different semantics. Other languages, such as <tt>C++</tt>, ensure
598 that only equivalent globals are ever merged (the "one definition rule" -
599 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
600 and <tt>weak_odr</tt> linkage types to indicate that the global will only
601 be merged with equivalent globals. These linkage types are otherwise the
602 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]605 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]606 visible, meaning that it participates in linkage and can be used to
607 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]608</dl>
609
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]610<p>The next two types of linkage are targeted for Microsoft Windows platform
611 only. They are designed to support importing (exporting) symbols from (to)
612 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]613
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]614<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]615 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]616 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]617 or variable via a global pointer to a pointer that is set up by the DLL
618 exporting the symbol. On Microsoft Windows targets, the pointer name is
619 formed by combining <code>__imp_</code> and the function or variable
620 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]621
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]623 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]624 pointer to a pointer in a DLL, so that it can be referenced with the
625 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
626 name is formed by combining <code>__imp_</code> and the function or
627 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]628</dl>
629
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]630<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
631 another module defined a "<tt>.LC0</tt>" variable and was linked with this
632 one, one of the two would be renamed, preventing a collision. Since
633 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
634 declarations), they are accessible outside of the current module.</p>
635
636<p>It is illegal for a function <i>declaration</i> to have any linkage type
637 other than "externally visible", <tt>dllimport</tt>
638 or <tt>extern_weak</tt>.</p>
639
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]640<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]641 or <tt>weak_odr</tt> linkages.</p>
642
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]643</div>
644
645<!-- ======================================================================= -->
646<div class="doc_subsection">
647 <a name="callingconv">Calling Conventions</a>
648</div>
649
650<div class="doc_text">
651
652<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]653 and <a href="#i_invoke">invokes</a> can all have an optional calling
654 convention specified for the call. The calling convention of any pair of
655 dynamic caller/callee must match, or the behavior of the program is
656 undefined. The following calling conventions are supported by LLVM, and more
657 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]658
659<dl>
660 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]661 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]662 specified) matches the target C calling conventions. This calling
663 convention supports varargs function calls and tolerates some mismatch in
664 the declared prototype and implemented declaration of the function (as
665 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]666
667 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]668 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]669 (e.g. by passing things in registers). This calling convention allows the
670 target to use whatever tricks it wants to produce fast code for the
671 target, without having to conform to an externally specified ABI
672 (Application Binary Interface). Implementations of this convention should
673 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
674 optimization</a> to be supported. This calling convention does not
675 support varargs and requires the prototype of all callees to exactly match
676 the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]677
678 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]679 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]680 as possible under the assumption that the call is not commonly executed.
681 As such, these calls often preserve all registers so that the call does
682 not break any live ranges in the caller side. This calling convention
683 does not support varargs and requires the prototype of all callees to
684 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]685
686 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]687 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]688 target-specific calling conventions to be used. Target specific calling
689 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]690</dl>
691
692<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]693 support Pascal conventions or any other well-known target-independent
694 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]695
696</div>
697
698<!-- ======================================================================= -->
699<div class="doc_subsection">
700 <a name="visibility">Visibility Styles</a>
701</div>
702
703<div class="doc_text">
704
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]705<p>All Global Variables and Functions have one of the following visibility
706 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]707
708<dl>
709 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]710 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]711 that the declaration is visible to other modules and, in shared libraries,
712 means that the declared entity may be overridden. On Darwin, default
713 visibility means that the declaration is visible to other modules. Default
714 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]715
716 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]717 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]718 object if they are in the same shared object. Usually, hidden visibility
719 indicates that the symbol will not be placed into the dynamic symbol
720 table, so no other module (executable or shared library) can reference it
721 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]722
723 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]724 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]725 the dynamic symbol table, but that references within the defining module
726 will bind to the local symbol. That is, the symbol cannot be overridden by
727 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]728</dl>
729
730</div>
731
732<!-- ======================================================================= -->
733<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]734 <a name="namedtypes">Named Types</a>
735</div>
736
737<div class="doc_text">
738
739<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]740 it easier to read the IR and make the IR more condensed (particularly when
741 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]742
743<div class="doc_code">
744<pre>
745%mytype = type { %mytype*, i32 }
746</pre>
747</div>
748
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]749<p>You may give a name to any <a href="#typesystem">type</a> except
750 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
751 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]752
753<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]754 and that you can therefore specify multiple names for the same type. This
755 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
756 uses structural typing, the name is not part of the type. When printing out
757 LLVM IR, the printer will pick <em>one name</em> to render all types of a
758 particular shape. This means that if you have code where two different
759 source types end up having the same LLVM type, that the dumper will sometimes
760 print the "wrong" or unexpected type. This is an important design point and
761 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]762
763</div>
764
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]765<!-- ======================================================================= -->
766<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]767 <a name="globalvars">Global Variables</a>
768</div>
769
770<div class="doc_text">
771
772<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]773 instead of run-time. Global variables may optionally be initialized, may
774 have an explicit section to be placed in, and may have an optional explicit
775 alignment specified. A variable may be defined as "thread_local", which
776 means that it will not be shared by threads (each thread will have a
777 separated copy of the variable). A variable may be defined as a global
778 "constant," which indicates that the contents of the variable
779 will <b>never</b> be modified (enabling better optimization, allowing the
780 global data to be placed in the read-only section of an executable, etc).
781 Note that variables that need runtime initialization cannot be marked
782 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]783
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]784<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
785 constant, even if the final definition of the global is not. This capability
786 can be used to enable slightly better optimization of the program, but
787 requires the language definition to guarantee that optimizations based on the
788 'constantness' are valid for the translation units that do not include the
789 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]790
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]791<p>As SSA values, global variables define pointer values that are in scope
792 (i.e. they dominate) all basic blocks in the program. Global variables
793 always define a pointer to their "content" type because they describe a
794 region of memory, and all memory objects in LLVM are accessed through
795 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]796
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]797<p>A global variable may be declared to reside in a target-specific numbered
798 address space. For targets that support them, address spaces may affect how
799 optimizations are performed and/or what target instructions are used to
800 access the variable. The default address space is zero. The address space
801 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]803<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]804 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]805
806<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]807 the alignment is set to zero, the alignment of the global is set by the
808 target to whatever it feels convenient. If an explicit alignment is
809 specified, the global is forced to have at least that much alignment. All
810 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]811
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]812<p>For example, the following defines a global in a numbered address space with
813 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]814
815<div class="doc_code">
816<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]817@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]818</pre>
819</div>
820
821</div>
822
823
824<!-- ======================================================================= -->
825<div class="doc_subsection">
826 <a name="functionstructure">Functions</a>
827</div>
828
829<div class="doc_text">
830
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]831<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
832 optional <a href="#linkage">linkage type</a>, an optional
833 <a href="#visibility">visibility style</a>, an optional
834 <a href="#callingconv">calling convention</a>, a return type, an optional
835 <a href="#paramattrs">parameter attribute</a> for the return type, a function
836 name, a (possibly empty) argument list (each with optional
837 <a href="#paramattrs">parameter attributes</a>), optional
838 <a href="#fnattrs">function attributes</a>, an optional section, an optional
839 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
840 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]841
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]842<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
843 optional <a href="#linkage">linkage type</a>, an optional
844 <a href="#visibility">visibility style</a>, an optional
845 <a href="#callingconv">calling convention</a>, a return type, an optional
846 <a href="#paramattrs">parameter attribute</a> for the return type, a function
847 name, a possibly empty list of arguments, an optional alignment, and an
848 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]849
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]850<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]851 (Control Flow Graph) for the function. Each basic block may optionally start
852 with a label (giving the basic block a symbol table entry), contains a list
853 of instructions, and ends with a <a href="#terminators">terminator</a>
854 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]855
856<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]857 executed on entrance to the function, and it is not allowed to have
858 predecessor basic blocks (i.e. there can not be any branches to the entry
859 block of a function). Because the block can have no predecessors, it also
860 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]861
862<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]863 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]864
865<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]866 the alignment is set to zero, the alignment of the function is set by the
867 target to whatever it feels convenient. If an explicit alignment is
868 specified, the function is forced to have at least that much alignment. All
869 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]870
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]871<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]872<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]873<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]874define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]875 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
876 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
877 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
878 [<a href="#gc">gc</a>] { ... }
879</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]880</div>
881
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]882</div>
883
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]884<!-- ======================================================================= -->
885<div class="doc_subsection">
886 <a name="aliasstructure">Aliases</a>
887</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]888
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]889<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]890
891<p>Aliases act as "second name" for the aliasee value (which can be either
892 function, global variable, another alias or bitcast of global value). Aliases
893 may have an optional <a href="#linkage">linkage type</a>, and an
894 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]895
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]896<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]897<div class="doc_code">
898<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]899@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]900</pre>
901</div>
902
903</div>
904
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]905<!-- ======================================================================= -->
906<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]907
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]908<div class="doc_text">
909
910<p>The return type and each parameter of a function type may have a set of
911 <i>parameter attributes</i> associated with them. Parameter attributes are
912 used to communicate additional information about the result or parameters of
913 a function. Parameter attributes are considered to be part of the function,
914 not of the function type, so functions with different parameter attributes
915 can have the same function type.</p>
916
917<p>Parameter attributes are simple keywords that follow the type specified. If
918 multiple parameter attributes are needed, they are space separated. For
919 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]920
921<div class="doc_code">
922<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]923declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]924declare i32 @atoi(i8 zeroext)
925declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]926</pre>
927</div>
928
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]929<p>Note that any attributes for the function result (<tt>nounwind</tt>,
930 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]931
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]932<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]933
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]934<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]935 <dt><tt><b>zeroext</b></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 zero-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 Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]940 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]941 <dd>This indicates to the code generator that the parameter or return value
942 should be sign-extended to a 32-bit value by the caller (for a parameter)
943 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]944
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]945 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]946 <dd>This indicates that this parameter or return value should be treated in a
947 special target-dependent fashion during while emitting code for a function
948 call or return (usually, by putting it in a register as opposed to memory,
949 though some targets use it to distinguish between two different kinds of
950 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]951
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]952 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]953 <dd>This indicates that the pointer parameter should really be passed by value
954 to the function. The attribute implies that a hidden copy of the pointee
955 is made between the caller and the callee, so the callee is unable to
956 modify the value in the callee. This attribute is only valid on LLVM
957 pointer arguments. It is generally used to pass structs and arrays by
958 value, but is also valid on pointers to scalars. The copy is considered
959 to belong to the caller not the callee (for example,
960 <tt><a href="#readonly">readonly</a></tt> functions should not write to
961 <tt>byval</tt> parameters). This is not a valid attribute for return
962 values. The byval attribute also supports specifying an alignment with
963 the align attribute. This has a target-specific effect on the code
964 generator that usually indicates a desired alignment for the synthesized
965 stack slot.</dd>
966
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]967 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]968 <dd>This indicates that the pointer parameter specifies the address of a
969 structure that is the return value of the function in the source program.
970 This pointer must be guaranteed by the caller to be valid: loads and
971 stores to the structure may be assumed by the callee to not to trap. This
972 may only be applied to the first parameter. This is not a valid attribute
973 for return values. </dd>
974
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]975 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]976 <dd>This indicates that the pointer does not alias any global or any other
977 parameter. The caller is responsible for ensuring that this is the
978 case. On a function return value, <tt>noalias</tt> additionally indicates
979 that the pointer does not alias any other pointers visible to the
980 caller. For further details, please see the discussion of the NoAlias
981 response in
982 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
983 analysis</a>.</dd>
984
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]985 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]986 <dd>This indicates that the callee does not make any copies of the pointer
987 that outlive the callee itself. This is not a valid attribute for return
988 values.</dd>
989
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]990 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]991 <dd>This indicates that the pointer parameter can be excised using the
992 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
993 attribute for return values.</dd>
994</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]995
996</div>
997
998<!-- ======================================================================= -->
999<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1000 <a name="gc">Garbage Collector Names</a>
1001</div>
1002
1003<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1004
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1005<p>Each function may specify a garbage collector name, which is simply a
1006 string:</p>
1007
1008<div class="doc_code">
1009<pre>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1010define void @f() gc "name" { ... }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1011</pre>
1012</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1013
1014<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1015 collector which will cause the compiler to alter its output in order to
1016 support the named garbage collection algorithm.</p>
1017
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1018</div>
1019
1020<!-- ======================================================================= -->
1021<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1022 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1023</div>
1024
1025<div class="doc_text">
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 set to communicate additional information about a
1028 function. Function attributes are considered to be part of the function, not
1029 of the function type, so functions with different parameter attributes can
1030 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1031
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1032<p>Function attributes are simple keywords that follow the type specified. If
1033 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1034
1035<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1036<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1037define void @f() noinline { ... }
1038define void @f() alwaysinline { ... }
1039define void @f() alwaysinline optsize { ... }
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1040define void @f() optsize { ... }
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1041</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1042</div>
1043
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1044<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1045 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1046 <dd>This attribute indicates that the inliner should attempt to inline this
1047 function into callers whenever possible, ignoring any active inlining size
1048 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1049
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1050 <dt><tt><b>inlinehint</b></tt></dt>
Dale Johannesen7fd6b0f2009-08-26 01:08:21 +0000[diff] [blame]1051 <dd>This attribute indicates that the source code contained a hint that inlining
1052 this function is desirable (such as the "inline" keyword in C/C++). It
1053 is just a hint; it imposes no requirements on the inliner.</dd>
1054
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1055 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1056 <dd>This attribute indicates that the inliner should never inline this
1057 function in any situation. This attribute may not be used together with
1058 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1059
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1060 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1061 <dd>This attribute suggests that optimization passes and code generator passes
1062 make choices that keep the code size of this function low, and otherwise
1063 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1064
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1065 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1066 <dd>This function attribute indicates that the function never returns
1067 normally. This produces undefined behavior at runtime if the function
1068 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1069
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1070 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1071 <dd>This function attribute indicates that the function never returns with an
1072 unwind or exceptional control flow. If the function does unwind, its
1073 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1074
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1075 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1076 <dd>This attribute indicates that the function computes its result (or decides
1077 to unwind an exception) based strictly on its arguments, without
1078 dereferencing any pointer arguments or otherwise accessing any mutable
1079 state (e.g. memory, control registers, etc) visible to caller functions.
1080 It does not write through any pointer arguments
1081 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1082 changes any state visible to callers. This means that it cannot unwind
1083 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1084 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1085
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1086 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1087 <dd>This attribute indicates that the function does not write through any
1088 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1089 arguments) or otherwise modify any state (e.g. memory, control registers,
1090 etc) visible to caller functions. It may dereference pointer arguments
1091 and read state that may be set in the caller. A readonly function always
1092 returns the same value (or unwinds an exception identically) when called
1093 with the same set of arguments and global state. It cannot unwind an
1094 exception by calling the <tt>C++</tt> exception throwing methods, but may
1095 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1096
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1097 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1098 <dd>This attribute indicates that the function should emit a stack smashing
1099 protector. It is in the form of a "canary"&mdash;a random value placed on
1100 the stack before the local variables that's checked upon return from the
1101 function to see if it has been overwritten. A heuristic is used to
1102 determine if a function needs stack protectors or not.<br>
1103<br>
1104 If a function that has an <tt>ssp</tt> attribute is inlined into a
1105 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1106 function will have an <tt>ssp</tt> attribute.</dd>
1107
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1108 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1109 <dd>This attribute indicates that the function should <em>always</em> emit a
1110 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1111 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1112<br>
1113 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1114 function that doesn't have an <tt>sspreq</tt> attribute or which has
1115 an <tt>ssp</tt> attribute, then the resulting function will have
1116 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1117
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1118 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1119 <dd>This attribute indicates that the code generator should not use a red
1120 zone, even if the target-specific ABI normally permits it.</dd>
1121
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1122 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1123 <dd>This attributes disables implicit floating point instructions.</dd>
1124
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1125 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1126 <dd>This attribute disables prologue / epilogue emission for the function.
1127 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1128</dl>
1129
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1130</div>
1131
1132<!-- ======================================================================= -->
1133<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1134 <a name="moduleasm">Module-Level Inline Assembly</a>
1135</div>
1136
1137<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1138
1139<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1140 the GCC "file scope inline asm" blocks. These blocks are internally
1141 concatenated by LLVM and treated as a single unit, but may be separated in
1142 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1143
1144<div class="doc_code">
1145<pre>
1146module asm "inline asm code goes here"
1147module asm "more can go here"
1148</pre>
1149</div>
1150
1151<p>The strings can contain any character by escaping non-printable characters.
1152 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]1153 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1154
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1155<p>The inline asm code is simply printed to the machine code .s file when
1156 assembly code is generated.</p>
1157
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1158</div>
1159
1160<!-- ======================================================================= -->
1161<div class="doc_subsection">
1162 <a name="datalayout">Data Layout</a>
1163</div>
1164
1165<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1166
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1167<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1168 data is to be laid out in memory. The syntax for the data layout is
1169 simply:</p>
1170
1171<div class="doc_code">
1172<pre>
1173target datalayout = "<i>layout specification</i>"
1174</pre>
1175</div>
1176
1177<p>The <i>layout specification</i> consists of a list of specifications
1178 separated by the minus sign character ('-'). Each specification starts with
1179 a letter and may include other information after the letter to define some
1180 aspect of the data layout. The specifications accepted are as follows:</p>
1181
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1182<dl>
1183 <dt><tt>E</tt></dt>
1184 <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]1185 bits with the most significance have the lowest address location.</dd>
1186
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1187 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1188 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1189 the bits with the least significance have the lowest address
1190 location.</dd>
1191
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1192 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1193 <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]1194 <i>preferred</i> alignments. All sizes are in bits. Specifying
1195 the <i>pref</i> alignment is optional. If omitted, the
1196 preceding <tt>:</tt> should be omitted too.</dd>
1197
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1198 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1199 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1200 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1201
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1202 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1203 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1204 <i>size</i>.</dd>
1205
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1206 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1207 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1208 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1209 (double).</dd>
1210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1211 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1212 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1213 <i>size</i>.</dd>
1214
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1215 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1216 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1217 <i>size</i>.</dd>
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1218
1219 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1220 <dd>This specifies a set of native integer widths for the target CPU
1221 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1222 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
1223 this set are considered to support most general arithmetic
1224 operations efficiently.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1225</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1226
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1227<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1228 default set of specifications which are then (possibly) overriden by the
1229 specifications in the <tt>datalayout</tt> keyword. The default specifications
1230 are given in this list:</p>
1231
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1232<ul>
1233 <li><tt>E</tt> - big endian</li>
1234 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1235 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1236 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1237 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1238 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1239 <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]1240 alignment of 64-bits</li>
1241 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1242 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1243 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1244 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1245 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1246 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1247</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1248
1249<p>When LLVM is determining the alignment for a given type, it uses the
1250 following rules:</p>
1251
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1252<ol>
1253 <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]1254 specification is used.</li>
1255
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1256 <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]1257 smallest integer type that is larger than the bitwidth of the sought type
1258 is used. If none of the specifications are larger than the bitwidth then
1259 the the largest integer type is used. For example, given the default
1260 specifications above, the i7 type will use the alignment of i8 (next
1261 largest) while both i65 and i256 will use the alignment of i64 (largest
1262 specified).</li>
1263
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1264 <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]1265 largest vector type that is smaller than the sought vector type will be
1266 used as a fall back. This happens because &lt;128 x double&gt; can be
1267 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1268</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1269
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1270</div>
1271
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1272<!-- ======================================================================= -->
1273<div class="doc_subsection">
1274 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1275</div>
1276
1277<div class="doc_text">
1278
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1279<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1280with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1281is undefined. Pointer values are associated with address ranges
1282according to the following rules:</p>
1283
1284<ul>
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1285 <li>A pointer value formed from a
1286 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1287 is associated with the addresses associated with the first operand
1288 of the <tt>getelementptr</tt>.</li>
1289 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1290 range of the variable's storage.</li>
1291 <li>The result value of an allocation instruction is associated with
1292 the address range of the allocated storage.</li>
1293 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1294 no address.</li>
1295 <li>A pointer value formed by an
1296 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1297 address ranges of all pointer values that contribute (directly or
1298 indirectly) to the computation of the pointer's value.</li>
1299 <li>The result value of a
1300 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1301 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1302 <li>An integer constant other than zero or a pointer value returned
1303 from a function not defined within LLVM may be associated with address
1304 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1305 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1306 allocated by mechanisms provided by LLVM.</li>
1307 </ul>
1308
1309<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1310<tt><a href="#i_load">load</a></tt> merely indicates the size and
1311alignment of the memory from which to load, as well as the
1312interpretation of the value. The first operand of a
1313<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1314and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1315
1316<p>Consequently, type-based alias analysis, aka TBAA, aka
1317<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1318LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1319additional information which specialized optimization passes may use
1320to implement type-based alias analysis.</p>
1321
1322</div>
1323
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1324<!-- *********************************************************************** -->
1325<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1326<!-- *********************************************************************** -->
1327
1328<div class="doc_text">
1329
1330<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1331 intermediate representation. Being typed enables a number of optimizations
1332 to be performed on the intermediate representation directly, without having
1333 to do extra analyses on the side before the transformation. A strong type
1334 system makes it easier to read the generated code and enables novel analyses
1335 and transformations that are not feasible to perform on normal three address
1336 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1337
1338</div>
1339
1340<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1341<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1342Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1343
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1344<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1345
1346<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1347
1348<table border="1" cellspacing="0" cellpadding="4">
1349 <tbody>
1350 <tr><th>Classification</th><th>Types</th></tr>
1351 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1352 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1353 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1354 </tr>
1355 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1356 <td><a href="#t_floating">floating point</a></td>
1357 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1358 </tr>
1359 <tr>
1360 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1361 <td><a href="#t_integer">integer</a>,
1362 <a href="#t_floating">floating point</a>,
1363 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1364 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1365 <a href="#t_struct">structure</a>,
1366 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1367 <a href="#t_label">label</a>,
1368 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1369 </td>
1370 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1371 <tr>
1372 <td><a href="#t_primitive">primitive</a></td>
1373 <td><a href="#t_label">label</a>,
1374 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1375 <a href="#t_floating">floating point</a>,
1376 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1377 </tr>
1378 <tr>
1379 <td><a href="#t_derived">derived</a></td>
1380 <td><a href="#t_integer">integer</a>,
1381 <a href="#t_array">array</a>,
1382 <a href="#t_function">function</a>,
1383 <a href="#t_pointer">pointer</a>,
1384 <a href="#t_struct">structure</a>,
1385 <a href="#t_pstruct">packed structure</a>,
1386 <a href="#t_vector">vector</a>,
1387 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1388 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1389 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1390 </tbody>
1391</table>
1392
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1393<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1394 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1395 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1396
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1397</div>
1398
1399<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1400<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1401
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1402<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1403
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1404<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1405 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1406
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1407</div>
1408
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1409<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1410<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1411
1412<div class="doc_text">
1413
1414<h5>Overview:</h5>
1415<p>The integer type is a very simple type that simply specifies an arbitrary
1416 bit width for the integer type desired. Any bit width from 1 bit to
1417 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1418
1419<h5>Syntax:</h5>
1420<pre>
1421 iN
1422</pre>
1423
1424<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1425 value.</p>
1426
1427<h5>Examples:</h5>
1428<table class="layout">
1429 <tr class="layout">
1430 <td class="left"><tt>i1</tt></td>
1431 <td class="left">a single-bit integer.</td>
1432 </tr>
1433 <tr class="layout">
1434 <td class="left"><tt>i32</tt></td>
1435 <td class="left">a 32-bit integer.</td>
1436 </tr>
1437 <tr class="layout">
1438 <td class="left"><tt>i1942652</tt></td>
1439 <td class="left">a really big integer of over 1 million bits.</td>
1440 </tr>
1441</table>
1442
1443<p>Note that the code generator does not yet support large integer types to be
1444 used as function return types. The specific limit on how large a return type
1445 the code generator can currently handle is target-dependent; currently it's
1446 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
1447
1448</div>
1449
1450<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1451<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1452
1453<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1454
1455<table>
1456 <tbody>
1457 <tr><th>Type</th><th>Description</th></tr>
1458 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1459 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1460 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1461 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1462 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1463 </tbody>
1464</table>
1465
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1466</div>
1467
1468<!-- _______________________________________________________________________ -->
1469<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1470
1471<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1472
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1473<h5>Overview:</h5>
1474<p>The void type does not represent any value and has no size.</p>
1475
1476<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1477<pre>
1478 void
1479</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1480
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1481</div>
1482
1483<!-- _______________________________________________________________________ -->
1484<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1485
1486<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1487
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1488<h5>Overview:</h5>
1489<p>The label type represents code labels.</p>
1490
1491<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1492<pre>
1493 label
1494</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1495
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1496</div>
1497
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1498<!-- _______________________________________________________________________ -->
1499<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1500
1501<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1502
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1503<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1504<p>The metadata type represents embedded metadata. No derived types may be
1505 created from metadata except for <a href="#t_function">function</a>
1506 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1507
1508<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1509<pre>
1510 metadata
1511</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1512
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1513</div>
1514
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1515
1516<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1517<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1518
1519<div class="doc_text">
1520
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1521<p>The real power in LLVM comes from the derived types in the system. This is
1522 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1523 useful types. Each of these types contain one or more element types which
1524 may be a primitive type, or another derived type. For example, it is
1525 possible to have a two dimensional array, using an array as the element type
1526 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1527
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1528</div>
1529
1530<!-- _______________________________________________________________________ -->
1531<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1532
1533<div class="doc_text">
1534
1535<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1536<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1537 sequentially in memory. The array type requires a size (number of elements)
1538 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1539
1540<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1541<pre>
1542 [&lt;# elements&gt; x &lt;elementtype&gt;]
1543</pre>
1544
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1545<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1546 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1547
1548<h5>Examples:</h5>
1549<table class="layout">
1550 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1551 <td class="left"><tt>[40 x i32]</tt></td>
1552 <td class="left">Array of 40 32-bit integer values.</td>
1553 </tr>
1554 <tr class="layout">
1555 <td class="left"><tt>[41 x i32]</tt></td>
1556 <td class="left">Array of 41 32-bit integer values.</td>
1557 </tr>
1558 <tr class="layout">
1559 <td class="left"><tt>[4 x i8]</tt></td>
1560 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1561 </tr>
1562</table>
1563<p>Here are some examples of multidimensional arrays:</p>
1564<table class="layout">
1565 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1566 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1567 <td class="left">3x4 array of 32-bit integer values.</td>
1568 </tr>
1569 <tr class="layout">
1570 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1571 <td class="left">12x10 array of single precision floating point values.</td>
1572 </tr>
1573 <tr class="layout">
1574 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1575 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1576 </tr>
1577</table>
1578
Dan Gohmanc668e252009-11-09 18:40:39 +0000[diff] [blame]1579<p>Except when the <tt>inbounds</tt> keyword is present, there is no limitation
1580 on indexing beyond the end of the array implied by the static type (though
1581 any loads or stores must of course be within the bounds of the allocated
1582 object!). This means that single-dimension 'variable sized array' addressing
1583 can be implemented in LLVM with a zero length array type. An implementation
1584 of 'pascal style arrays' in LLVM could use the type
1585 "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1586
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1587<p>Note that the code generator does not yet support large aggregate types to be
1588 used as function return types. The specific limit on how large an aggregate
1589 return type the code generator can currently handle is target-dependent, and
1590 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1591
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1592</div>
1593
1594<!-- _______________________________________________________________________ -->
1595<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1596
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1597<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1598
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1599<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1600<p>The function type can be thought of as a function signature. It consists of
1601 a return type and a list of formal parameter types. The return type of a
1602 function type is a scalar type, a void type, or a struct type. If the return
1603 type is a struct type then all struct elements must be of first class types,
1604 and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1605
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1606<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1607<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1608 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1609</pre>
1610
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1611<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]1612 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1613 which indicates that the function takes a variable number of arguments.
1614 Variable argument functions can access their arguments with
1615 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1616 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1617 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1618
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1619<h5>Examples:</h5>
1620<table class="layout">
1621 <tr class="layout">
1622 <td class="left"><tt>i32 (i32)</tt></td>
1623 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1624 </td>
1625 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1626 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1627 </tt></td>
1628 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1629 an <tt>i16</tt> that should be sign extended and a
1630 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1631 <tt>float</tt>.
1632 </td>
1633 </tr><tr class="layout">
1634 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1635 <td class="left">A vararg function that takes at least one
1636 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1637 which returns an integer. This is the signature for <tt>printf</tt> in
1638 LLVM.
1639 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1640 </tr><tr class="layout">
1641 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1642 <td class="left">A function taking an <tt>i32</tt>, returning a
1643 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1644 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1645 </tr>
1646</table>
1647
1648</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1650<!-- _______________________________________________________________________ -->
1651<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1652
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1653<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1654
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1655<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1656<p>The structure type is used to represent a collection of data members together
1657 in memory. The packing of the field types is defined to match the ABI of the
1658 underlying processor. The elements of a structure may be any type that has a
1659 size.</p>
1660
1661<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1662 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1663 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1664
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1665<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1666<pre>
1667 { &lt;type list&gt; }
1668</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1669
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1670<h5>Examples:</h5>
1671<table class="layout">
1672 <tr class="layout">
1673 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1674 <td class="left">A triple of three <tt>i32</tt> values</td>
1675 </tr><tr class="layout">
1676 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1677 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1678 second element is a <a href="#t_pointer">pointer</a> to a
1679 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1680 an <tt>i32</tt>.</td>
1681 </tr>
1682</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1683
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1684<p>Note that the code generator does not yet support large aggregate types to be
1685 used as function return types. The specific limit on how large an aggregate
1686 return type the code generator can currently handle is target-dependent, and
1687 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1688
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1689</div>
1690
1691<!-- _______________________________________________________________________ -->
1692<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1693</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1694
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1695<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1696
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1697<h5>Overview:</h5>
1698<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1699 together in memory. There is no padding between fields. Further, the
1700 alignment of a packed structure is 1 byte. The elements of a packed
1701 structure may be any type that has a size.</p>
1702
1703<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1704 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1705 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1706
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1707<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1708<pre>
1709 &lt; { &lt;type list&gt; } &gt;
1710</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1711
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1712<h5>Examples:</h5>
1713<table class="layout">
1714 <tr class="layout">
1715 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1716 <td class="left">A triple of three <tt>i32</tt> values</td>
1717 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1718 <td class="left">
1719<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1720 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1721 second element is a <a href="#t_pointer">pointer</a> to a
1722 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1723 an <tt>i32</tt>.</td>
1724 </tr>
1725</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1726
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1727</div>
1728
1729<!-- _______________________________________________________________________ -->
1730<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1731
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1732<div class="doc_text">
1733
1734<h5>Overview:</h5>
1735<p>As in many languages, the pointer type represents a pointer or reference to
1736 another object, which must live in memory. Pointer types may have an optional
1737 address space attribute defining the target-specific numbered address space
1738 where the pointed-to object resides. The default address space is zero.</p>
1739
1740<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1741 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1742
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1743<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1744<pre>
1745 &lt;type&gt; *
1746</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1747
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1748<h5>Examples:</h5>
1749<table class="layout">
1750 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1751 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1752 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1753 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1754 </tr>
1755 <tr class="layout">
1756 <td class="left"><tt>i32 (i32 *) *</tt></td>
1757 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1758 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1759 <tt>i32</tt>.</td>
1760 </tr>
1761 <tr class="layout">
1762 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1763 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1764 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1765 </tr>
1766</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1767
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1768</div>
1769
1770<!-- _______________________________________________________________________ -->
1771<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1772
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1773<div class="doc_text">
1774
1775<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1776<p>A vector type is a simple derived type that represents a vector of elements.
1777 Vector types are used when multiple primitive data are operated in parallel
1778 using a single instruction (SIMD). A vector type requires a size (number of
1779 elements) and an underlying primitive data type. Vectors must have a power
1780 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1781 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1782
1783<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1784<pre>
1785 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1786</pre>
1787
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1788<p>The number of elements is a constant integer value; elementtype may be any
1789 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1790
1791<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1792<table class="layout">
1793 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1794 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1795 <td class="left">Vector of 4 32-bit integer values.</td>
1796 </tr>
1797 <tr class="layout">
1798 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1799 <td class="left">Vector of 8 32-bit floating-point values.</td>
1800 </tr>
1801 <tr class="layout">
1802 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1803 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1804 </tr>
1805</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1806
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1807<p>Note that the code generator does not yet support large vector types to be
1808 used as function return types. The specific limit on how large a vector
1809 return type codegen can currently handle is target-dependent; currently it's
1810 often a few times longer than a hardware vector register.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1811
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1812</div>
1813
1814<!-- _______________________________________________________________________ -->
1815<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1816<div class="doc_text">
1817
1818<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1819<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1820 corresponds (for example) to the C notion of a forward declared structure
1821 type. In LLVM, opaque types can eventually be resolved to any type (not just
1822 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1823
1824<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1825<pre>
1826 opaque
1827</pre>
1828
1829<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1830<table class="layout">
1831 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1832 <td class="left"><tt>opaque</tt></td>
1833 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1834 </tr>
1835</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1836
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1837</div>
1838
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1839<!-- ======================================================================= -->
1840<div class="doc_subsection">
1841 <a name="t_uprefs">Type Up-references</a>
1842</div>
1843
1844<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1845
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1846<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1847<p>An "up reference" allows you to refer to a lexically enclosing type without
1848 requiring it to have a name. For instance, a structure declaration may
1849 contain a pointer to any of the types it is lexically a member of. Example
1850 of up references (with their equivalent as named type declarations)
1851 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1852
1853<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1854 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1855 { \2 }* %y = type { %y }*
1856 \1* %z = type %z*
1857</pre>
1858
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1859<p>An up reference is needed by the asmprinter for printing out cyclic types
1860 when there is no declared name for a type in the cycle. Because the
1861 asmprinter does not want to print out an infinite type string, it needs a
1862 syntax to handle recursive types that have no names (all names are optional
1863 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1864
1865<h5>Syntax:</h5>
1866<pre>
1867 \&lt;level&gt;
1868</pre>
1869
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1870<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]1871
1872<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1873<table class="layout">
1874 <tr class="layout">
1875 <td class="left"><tt>\1*</tt></td>
1876 <td class="left">Self-referential pointer.</td>
1877 </tr>
1878 <tr class="layout">
1879 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1880 <td class="left">Recursive structure where the upref refers to the out-most
1881 structure.</td>
1882 </tr>
1883</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1884
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1885</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1886
1887<!-- *********************************************************************** -->
1888<div class="doc_section"> <a name="constants">Constants</a> </div>
1889<!-- *********************************************************************** -->
1890
1891<div class="doc_text">
1892
1893<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1894 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1895
1896</div>
1897
1898<!-- ======================================================================= -->
1899<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1900
1901<div class="doc_text">
1902
1903<dl>
1904 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1905 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1906 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1907
1908 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1909 <dd>Standard integers (such as '4') are constants of
1910 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1911 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1912
1913 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1914 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1915 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1916 notation (see below). The assembler requires the exact decimal value of a
1917 floating-point constant. For example, the assembler accepts 1.25 but
1918 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1919 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1920
1921 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1922 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1923 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1924</dl>
1925
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1926<p>The one non-intuitive notation for constants is the hexadecimal form of
1927 floating point constants. For example, the form '<tt>double
1928 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1929 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1930 constants are required (and the only time that they are generated by the
1931 disassembler) is when a floating point constant must be emitted but it cannot
1932 be represented as a decimal floating point number in a reasonable number of
1933 digits. For example, NaN's, infinities, and other special values are
1934 represented in their IEEE hexadecimal format so that assembly and disassembly
1935 do not cause any bits to change in the constants.</p>
1936
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1937<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1938 represented using the 16-digit form shown above (which matches the IEEE754
1939 representation for double); float values must, however, be exactly
1940 representable as IEE754 single precision. Hexadecimal format is always used
1941 for long double, and there are three forms of long double. The 80-bit format
1942 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1943 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1944 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1945 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1946 currently supported target uses this format. Long doubles will only work if
1947 they match the long double format on your target. All hexadecimal formats
1948 are big-endian (sign bit at the left).</p>
1949
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1950</div>
1951
1952<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1953<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]1954<a name="aggregateconstants"></a> <!-- old anchor -->
1955<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1956</div>
1957
1958<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1959
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1960<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1961 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1962
1963<dl>
1964 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1965 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1966 type definitions (a comma separated list of elements, surrounded by braces
1967 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1968 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1969 Structure constants must have <a href="#t_struct">structure type</a>, and
1970 the number and types of elements must match those specified by the
1971 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1972
1973 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1974 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1975 definitions (a comma separated list of elements, surrounded by square
1976 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1977 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1978 the number and types of elements must match those specified by the
1979 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1980
1981 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1982 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1983 definitions (a comma separated list of elements, surrounded by
1984 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1985 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1986 have <a href="#t_vector">vector type</a>, and the number and types of
1987 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1988
1989 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1990 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1991 value to zero of <em>any</em> type, including scalar and aggregate types.
1992 This is often used to avoid having to print large zero initializers
1993 (e.g. for large arrays) and is always exactly equivalent to using explicit
1994 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1995
1996 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]1997 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1998 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1999 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2000 be interpreted as part of the instruction stream, metadata is a place to
2001 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2002</dl>
2003
2004</div>
2005
2006<!-- ======================================================================= -->
2007<div class="doc_subsection">
2008 <a name="globalconstants">Global Variable and Function Addresses</a>
2009</div>
2010
2011<div class="doc_text">
2012
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2013<p>The addresses of <a href="#globalvars">global variables</a>
2014 and <a href="#functionstructure">functions</a> are always implicitly valid
2015 (link-time) constants. These constants are explicitly referenced when
2016 the <a href="#identifiers">identifier for the global</a> is used and always
2017 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2018 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2019
2020<div class="doc_code">
2021<pre>
2022@X = global i32 17
2023@Y = global i32 42
2024@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2025</pre>
2026</div>
2027
2028</div>
2029
2030<!-- ======================================================================= -->
2031<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2032<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2033
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2034<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2035 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2036 Undefined values may be of any type (other than label or void) and be used
2037 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2038
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2039<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2040 program is well defined no matter what value is used. This gives the
2041 compiler more freedom to optimize. Here are some examples of (potentially
2042 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2043
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2044
2045<div class="doc_code">
2046<pre>
2047 %A = add %X, undef
2048 %B = sub %X, undef
2049 %C = xor %X, undef
2050Safe:
2051 %A = undef
2052 %B = undef
2053 %C = undef
2054</pre>
2055</div>
2056
2057<p>This is safe because all of the output bits are affected by the undef bits.
2058Any output bit can have a zero or one depending on the input bits.</p>
2059
2060<div class="doc_code">
2061<pre>
2062 %A = or %X, undef
2063 %B = and %X, undef
2064Safe:
2065 %A = -1
2066 %B = 0
2067Unsafe:
2068 %A = undef
2069 %B = undef
2070</pre>
2071</div>
2072
2073<p>These logical operations have bits that are not always affected by the input.
2074For example, if "%X" has a zero bit, then the output of the 'and' operation will
2075always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2076such, it is unsafe to optimize or assume that the result of the and is undef.
2077However, it is safe to assume that all bits of the undef could be 0, and
2078optimize the and to 0. Likewise, it is safe to assume that all the bits of
2079the undef operand to the or could be set, allowing the or to be folded to
2080-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2081
2082<div class="doc_code">
2083<pre>
2084 %A = select undef, %X, %Y
2085 %B = select undef, 42, %Y
2086 %C = select %X, %Y, undef
2087Safe:
2088 %A = %X (or %Y)
2089 %B = 42 (or %Y)
2090 %C = %Y
2091Unsafe:
2092 %A = undef
2093 %B = undef
2094 %C = undef
2095</pre>
2096</div>
2097
2098<p>This set of examples show that undefined select (and conditional branch)
2099conditions can go "either way" but they have to come from one of the two
2100operands. In the %A example, if %X and %Y were both known to have a clear low
2101bit, then %A would have to have a cleared low bit. However, in the %C example,
2102the optimizer is allowed to assume that the undef operand could be the same as
2103%Y, allowing the whole select to be eliminated.</p>
2104
2105
2106<div class="doc_code">
2107<pre>
2108 %A = xor undef, undef
2109
2110 %B = undef
2111 %C = xor %B, %B
2112
2113 %D = undef
2114 %E = icmp lt %D, 4
2115 %F = icmp gte %D, 4
2116
2117Safe:
2118 %A = undef
2119 %B = undef
2120 %C = undef
2121 %D = undef
2122 %E = undef
2123 %F = undef
2124</pre>
2125</div>
2126
2127<p>This example points out that two undef operands are not necessarily the same.
2128This can be surprising to people (and also matches C semantics) where they
2129assume that "X^X" is always zero, even if X is undef. This isn't true for a
2130number of reasons, but the short answer is that an undef "variable" can
2131arbitrarily change its value over its "live range". This is true because the
2132"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2133logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2134so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2135to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2136would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2137
2138<div class="doc_code">
2139<pre>
2140 %A = fdiv undef, %X
2141 %B = fdiv %X, undef
2142Safe:
2143 %A = undef
2144b: unreachable
2145</pre>
2146</div>
2147
2148<p>These examples show the crucial difference between an <em>undefined
2149value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2150allowed to have an arbitrary bit-pattern. This means that the %A operation
2151can be constant folded to undef because the undef could be an SNaN, and fdiv is
2152not (currently) defined on SNaN's. However, in the second example, we can make
2153a more aggressive assumption: because the undef is allowed to be an arbitrary
2154value, 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]2155has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2156does not execute at all. This allows us to delete the divide and all code after
2157it: since the undefined operation "can't happen", the optimizer can assume that
2158it occurs in dead code.
2159</p>
2160
2161<div class="doc_code">
2162<pre>
2163a: store undef -> %X
2164b: store %X -> undef
2165Safe:
2166a: &lt;deleted&gt;
2167b: unreachable
2168</pre>
2169</div>
2170
2171<p>These examples reiterate the fdiv example: a store "of" an undefined value
2172can be assumed to not have any effect: we can assume that the value is
2173overwritten with bits that happen to match what was already there. However, a
2174store "to" an undefined location could clobber arbitrary memory, therefore, it
2175has undefined behavior.</p>
2176
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2177</div>
2178
2179<!-- ======================================================================= -->
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2180<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2181 Blocks</a></div>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2182<div class="doc_text">
2183
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2184<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2185
2186<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner24f2e852009-10-27 21:49:40 +0000[diff] [blame]2187 basic block in the specified function, and always has an i8* type. Taking
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2188 the address of the entry block is illegal.</p>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2189
2190<p>This value only has defined behavior when used as an operand to the
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2191 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2192 against null. Pointer equality tests between labels addresses is undefined
2193 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2194 equal to the null pointer. This may also be passed around as an opaque
2195 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner0bae7b32009-10-27 21:44:20 +0000[diff] [blame]2196 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2197 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2198
2199<p>Finally, some targets may provide defined semantics when
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2200 using the value as the operand to an inline assembly, but that is target
2201 specific.
2202 </p>
2203
2204</div>
2205
2206
2207<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2208<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2209</div>
2210
2211<div class="doc_text">
2212
2213<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2214 to be used as constants. Constant expressions may be of
2215 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2216 operation that does not have side effects (e.g. load and call are not
2217 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2218
2219<dl>
2220 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2221 <dd>Truncate a constant to another type. The bit size of CST must be larger
2222 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2223
2224 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2225 <dd>Zero extend a constant to another type. The bit size of CST must be
2226 smaller or equal to the bit size of TYPE. Both types must be
2227 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2228
2229 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2230 <dd>Sign extend a constant to another type. The bit size of CST must be
2231 smaller or equal to the bit size of TYPE. Both types must be
2232 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2233
2234 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2235 <dd>Truncate a floating point constant to another floating point type. The
2236 size of CST must be larger than the size of TYPE. Both types must be
2237 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2238
2239 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2240 <dd>Floating point extend a constant to another type. The size of CST must be
2241 smaller or equal to the size of TYPE. Both types must be floating
2242 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2243
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2244 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2245 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2246 constant. TYPE must be a scalar or vector integer type. CST must be of
2247 scalar or vector floating point type. Both CST and TYPE must be scalars,
2248 or vectors of the same number of elements. If the value won't fit in the
2249 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2250
2251 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2252 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2253 constant. TYPE must be a scalar or vector integer type. CST must be of
2254 scalar or vector floating point type. Both CST and TYPE must be scalars,
2255 or vectors of the same number of elements. If the value won't fit in the
2256 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2257
2258 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2259 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2260 constant. TYPE must be a scalar or vector floating point type. CST must be
2261 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2262 vectors of the same number of elements. If the value won't fit in the
2263 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2264
2265 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2266 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2267 constant. TYPE must be a scalar or vector floating point type. CST must be
2268 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2269 vectors of the same number of elements. If the value won't fit in the
2270 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2271
2272 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2273 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2274 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2275 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2276 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2277
2278 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2279 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2280 type. CST must be of integer type. The CST value is zero extended,
2281 truncated, or unchanged to make it fit in a pointer size. This one is
2282 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2283
2284 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2285 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2286 are the same as those for the <a href="#i_bitcast">bitcast
2287 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2288
2289 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2290 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2291 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2292 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2293 instruction, the index list may have zero or more indexes, which are
2294 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2295
2296 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2297 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2298
2299 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2300 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2301
2302 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2303 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2304
2305 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2306 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2307 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2308
2309 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2310 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2311 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2312
2313 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2314 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2315 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2316
2317 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2318 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2319 be any of the <a href="#binaryops">binary</a>
2320 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2321 on operands are the same as those for the corresponding instruction
2322 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2323</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2324
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2325</div>
2326
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2327<!-- ======================================================================= -->
2328<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2329</div>
2330
2331<div class="doc_text">
2332
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2333<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2334 stream without affecting the behaviour of the program. There are two
2335 metadata primitives, strings and nodes. All metadata has the
2336 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2337 point ('<tt>!</tt>').</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2338
2339<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2340 any character by escaping non-printable characters with "\xx" where "xx" is
2341 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2342
2343<p>Metadata nodes are represented with notation similar to structure constants
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2344 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2345 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2346 10}</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2347
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2348<p>A metadata node will attempt to track changes to the values it holds. In the
2349 event that a value is deleted, it will be replaced with a typeless
2350 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2351
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2352<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2353 the program that isn't available in the instructions, or that isn't easily
2354 computable. Similarly, the code generator may expect a certain metadata
2355 format to be used to express debugging information.</p>
2356
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2357</div>
2358
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2359<!-- *********************************************************************** -->
2360<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2361<!-- *********************************************************************** -->
2362
2363<!-- ======================================================================= -->
2364<div class="doc_subsection">
2365<a name="inlineasm">Inline Assembler Expressions</a>
2366</div>
2367
2368<div class="doc_text">
2369
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2370<p>LLVM supports inline assembler expressions (as opposed
2371 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2372 a special value. This value represents the inline assembler as a string
2373 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2374 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2375 expression has side effects, and a flag indicating whether the function
2376 containing the asm needs to align its stack conservatively. An example
2377 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2378
2379<div class="doc_code">
2380<pre>
2381i32 (i32) asm "bswap $0", "=r,r"
2382</pre>
2383</div>
2384
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2385<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2386 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2387 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2388
2389<div class="doc_code">
2390<pre>
2391%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2392</pre>
2393</div>
2394
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2395<p>Inline asms with side effects not visible in the constraint list must be
2396 marked as having side effects. This is done through the use of the
2397 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2398
2399<div class="doc_code">
2400<pre>
2401call void asm sideeffect "eieio", ""()
2402</pre>
2403</div>
2404
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2405<p>In some cases inline asms will contain code that will not work unless the
2406 stack is aligned in some way, such as calls or SSE instructions on x86,
2407 yet will not contain code that does that alignment within the asm.
2408 The compiler should make conservative assumptions about what the asm might
2409 contain and should generate its usual stack alignment code in the prologue
2410 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2411
2412<div class="doc_code">
2413<pre>
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2414call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2415</pre>
2416</div>
2417
2418<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2419 first.</p>
2420
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2421<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2422 documented here. Constraints on what can be done (e.g. duplication, moving,
2423 etc need to be documented). This is probably best done by reference to
2424 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2425
2426</div>
2427
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2428
2429<!-- *********************************************************************** -->
2430<div class="doc_section">
2431 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2432</div>
2433<!-- *********************************************************************** -->
2434
2435<p>LLVM has a number of "magic" global variables that contain data that affect
2436code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2437of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2438section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2439by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2440
2441<!-- ======================================================================= -->
2442<div class="doc_subsection">
2443<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2444</div>
2445
2446<div class="doc_text">
2447
2448<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2449href="#linkage_appending">appending linkage</a>. This array contains a list of
2450pointers to global variables and functions which may optionally have a pointer
2451cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2452
2453<pre>
2454 @X = global i8 4
2455 @Y = global i32 123
2456
2457 @llvm.used = appending global [2 x i8*] [
2458 i8* @X,
2459 i8* bitcast (i32* @Y to i8*)
2460 ], section "llvm.metadata"
2461</pre>
2462
2463<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2464compiler, assembler, and linker are required to treat the symbol as if there is
2465a reference to the global that it cannot see. For example, if a variable has
2466internal linkage and no references other than that from the <tt>@llvm.used</tt>
2467list, it cannot be deleted. This is commonly used to represent references from
2468inline asms and other things the compiler cannot "see", and corresponds to
2469"attribute((used))" in GNU C.</p>
2470
2471<p>On some targets, the code generator must emit a directive to the assembler or
2472object file to prevent the assembler and linker from molesting the symbol.</p>
2473
2474</div>
2475
2476<!-- ======================================================================= -->
2477<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2478<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2479</div>
2480
2481<div class="doc_text">
2482
2483<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2484<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2485touching the symbol. On targets that support it, this allows an intelligent
2486linker to optimize references to the symbol without being impeded as it would be
2487by <tt>@llvm.used</tt>.</p>
2488
2489<p>This is a rare construct that should only be used in rare circumstances, and
2490should not be exposed to source languages.</p>
2491
2492</div>
2493
2494<!-- ======================================================================= -->
2495<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2496<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2497</div>
2498
2499<div class="doc_text">
2500
2501<p>TODO: Describe this.</p>
2502
2503</div>
2504
2505<!-- ======================================================================= -->
2506<div class="doc_subsection">
2507<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2508</div>
2509
2510<div class="doc_text">
2511
2512<p>TODO: Describe this.</p>
2513
2514</div>
2515
2516
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2517<!-- *********************************************************************** -->
2518<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2519<!-- *********************************************************************** -->
2520
2521<div class="doc_text">
2522
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2523<p>The LLVM instruction set consists of several different classifications of
2524 instructions: <a href="#terminators">terminator
2525 instructions</a>, <a href="#binaryops">binary instructions</a>,
2526 <a href="#bitwiseops">bitwise binary instructions</a>,
2527 <a href="#memoryops">memory instructions</a>, and
2528 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2529
2530</div>
2531
2532<!-- ======================================================================= -->
2533<div class="doc_subsection"> <a name="terminators">Terminator
2534Instructions</a> </div>
2535
2536<div class="doc_text">
2537
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2538<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2539 in a program ends with a "Terminator" instruction, which indicates which
2540 block should be executed after the current block is finished. These
2541 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2542 control flow, not values (the one exception being the
2543 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2544
2545<p>There are six different terminator instructions: the
2546 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2547 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2548 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendlingb4ae2292009-11-02 00:25:26 +0000[diff] [blame]2549 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2550 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2551 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2552 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2553
2554</div>
2555
2556<!-- _______________________________________________________________________ -->
2557<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2558Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2559
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2560<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2561
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2562<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2563<pre>
2564 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]2565 ret void <i>; Return from void function</i>
2566</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2567
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2568<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2569<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2570 a value) from a function back to the caller.</p>
2571
2572<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2573 value and then causes control flow, and one that just causes control flow to
2574 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2575
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2576<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2577<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2578 return value. The type of the return value must be a
2579 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2580
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2581<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2582 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2583 value or a return value with a type that does not match its type, or if it
2584 has a void return type and contains a '<tt>ret</tt>' instruction with a
2585 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2586
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2587<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2588<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2589 the calling function's context. If the caller is a
2590 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2591 instruction after the call. If the caller was an
2592 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2593 the beginning of the "normal" destination block. If the instruction returns
2594 a value, that value shall set the call or invoke instruction's return
2595 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2596
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2597<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2598<pre>
2599 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2600 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2601 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]2602</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2603
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2604<p>Note that the code generator does not yet fully support large
2605 return values. The specific sizes that are currently supported are
2606 dependent on the target. For integers, on 32-bit targets the limit
2607 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2608 For aggregate types, the current limits are dependent on the element
2609 types; for example targets are often limited to 2 total integer
2610 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2611
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2612</div>
2613<!-- _______________________________________________________________________ -->
2614<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2615
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2616<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2617
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2618<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2619<pre>
2620 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]2621</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2622
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2623<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2624<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2625 different basic block in the current function. There are two forms of this
2626 instruction, corresponding to a conditional branch and an unconditional
2627 branch.</p>
2628
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2629<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2630<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2631 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2632 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2633 target.</p>
2634
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2635<h5>Semantics:</h5>
2636<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2637 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2638 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2639 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2640
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2641<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2642<pre>
2643Test:
2644 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2645 br i1 %cond, label %IfEqual, label %IfUnequal
2646IfEqual:
2647 <a href="#i_ret">ret</a> i32 1
2648IfUnequal:
2649 <a href="#i_ret">ret</a> i32 0
2650</pre>
2651
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2652</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2653
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2654<!-- _______________________________________________________________________ -->
2655<div class="doc_subsubsection">
2656 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2657</div>
2658
2659<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2660
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2661<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2662<pre>
2663 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2664</pre>
2665
2666<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2667<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]2668 several different places. It is a generalization of the '<tt>br</tt>'
2669 instruction, allowing a branch to occur to one of many possible
2670 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2671
2672<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2673<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2674 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2675 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2676 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2677
2678<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2679<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2680 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2681 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2682 transferred to the corresponding destination; otherwise, control flow is
2683 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2684
2685<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2686<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2687 <tt>switch</tt> instruction, this instruction may be code generated in
2688 different ways. For example, it could be generated as a series of chained
2689 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2690
2691<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2692<pre>
2693 <i>; Emulate a conditional br instruction</i>
2694 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2695 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2696
2697 <i>; Emulate an unconditional br instruction</i>
2698 switch i32 0, label %dest [ ]
2699
2700 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2701 switch i32 %val, label %otherwise [ i32 0, label %onzero
2702 i32 1, label %onone
2703 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2704</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2705
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2706</div>
2707
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2708
2709<!-- _______________________________________________________________________ -->
2710<div class="doc_subsubsection">
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2711 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2712</div>
2713
2714<div class="doc_text">
2715
2716<h5>Syntax:</h5>
2717<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2718 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2719</pre>
2720
2721<h5>Overview:</h5>
2722
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2723<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2724 within the current function, whose address is specified by
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2725 "<tt>address</tt>". Address must be derived from a <a
2726 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2727
2728<h5>Arguments:</h5>
2729
2730<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2731 rest of the arguments indicate the full set of possible destinations that the
2732 address may point to. Blocks are allowed to occur multiple times in the
2733 destination list, though this isn't particularly useful.</p>
2734
2735<p>This destination list is required so that dataflow analysis has an accurate
2736 understanding of the CFG.</p>
2737
2738<h5>Semantics:</h5>
2739
2740<p>Control transfers to the block specified in the address argument. All
2741 possible destination blocks must be listed in the label list, otherwise this
2742 instruction has undefined behavior. This implies that jumps to labels
2743 defined in other functions have undefined behavior as well.</p>
2744
2745<h5>Implementation:</h5>
2746
2747<p>This is typically implemented with a jump through a register.</p>
2748
2749<h5>Example:</h5>
2750<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2751 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2752</pre>
2753
2754</div>
2755
2756
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2757<!-- _______________________________________________________________________ -->
2758<div class="doc_subsubsection">
2759 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2760</div>
2761
2762<div class="doc_text">
2763
2764<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2765<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2766 &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]2767 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2768</pre>
2769
2770<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2771<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2772 function, with the possibility of control flow transfer to either the
2773 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2774 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2775 control flow will return to the "normal" label. If the callee (or any
2776 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2777 instruction, control is interrupted and continued at the dynamically nearest
2778 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2779
2780<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2781<p>This instruction requires several arguments:</p>
2782
2783<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2784 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2785 convention</a> the call should use. If none is specified, the call
2786 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2787
2788 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2789 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2790 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2792 <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]2793 function value being invoked. In most cases, this is a direct function
2794 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2795 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2796
2797 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2798 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2799
2800 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2801 signature argument types. If the function signature indicates the
2802 function accepts a variable number of arguments, the extra arguments can
2803 be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2804
2805 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2806 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2807
2808 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2809 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2810
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2811 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2812 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2813 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2814</ol>
2815
2816<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2817<p>This instruction is designed to operate as a standard
2818 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2819 primary difference is that it establishes an association with a label, which
2820 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2821
2822<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2823 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2824 exception. Additionally, this is important for implementation of
2825 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2826
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2827<p>For the purposes of the SSA form, the definition of the value returned by the
2828 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2829 block to the "normal" label. If the callee unwinds then no return value is
2830 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2831
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2832<h5>Example:</h5>
2833<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2834 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2835 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2836 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2837 unwind label %TestCleanup <i>; {i32}:retval set</i>
2838</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2839
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2840</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2841
2842<!-- _______________________________________________________________________ -->
2843
2844<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2845Instruction</a> </div>
2846
2847<div class="doc_text">
2848
2849<h5>Syntax:</h5>
2850<pre>
2851 unwind
2852</pre>
2853
2854<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2855<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2856 at the first callee in the dynamic call stack which used
2857 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2858 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2859
2860<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2861<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2862 immediately halt. The dynamic call stack is then searched for the
2863 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2864 Once found, execution continues at the "exceptional" destination block
2865 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2866 instruction in the dynamic call chain, undefined behavior results.</p>
2867
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2868</div>
2869
2870<!-- _______________________________________________________________________ -->
2871
2872<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2873Instruction</a> </div>
2874
2875<div class="doc_text">
2876
2877<h5>Syntax:</h5>
2878<pre>
2879 unreachable
2880</pre>
2881
2882<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2883<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2884 instruction is used to inform the optimizer that a particular portion of the
2885 code is not reachable. This can be used to indicate that the code after a
2886 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2887
2888<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2889<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2890
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2891</div>
2892
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2893<!-- ======================================================================= -->
2894<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2895
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2896<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2897
2898<p>Binary operators are used to do most of the computation in a program. They
2899 require two operands of the same type, execute an operation on them, and
2900 produce a single value. The operands might represent multiple data, as is
2901 the case with the <a href="#t_vector">vector</a> data type. The result value
2902 has the same type as its operands.</p>
2903
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2904<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2905
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2906</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2907
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2908<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2909<div class="doc_subsubsection">
2910 <a name="i_add">'<tt>add</tt>' Instruction</a>
2911</div>
2912
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2913<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2914
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2915<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2916<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2917 &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]2918 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2919 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2920 &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]2921</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2922
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2923<h5>Overview:</h5>
2924<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2925
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2926<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2927<p>The two arguments to the '<tt>add</tt>' instruction must
2928 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2929 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2930
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2931<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2932<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2933
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2934<p>If the sum has unsigned overflow, the result returned is the mathematical
2935 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]2936
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2937<p>Because LLVM integers use a two's complement representation, this instruction
2938 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2939
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2940<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2941 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2942 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2943 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2944
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2945<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2946<pre>
2947 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2948</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2949
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2950</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2951
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2952<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2953<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2954 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2955</div>
2956
2957<div class="doc_text">
2958
2959<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2960<pre>
2961 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2962</pre>
2963
2964<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2965<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2966
2967<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2968<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2969 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2970 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2971
2972<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2973<p>The value produced is the floating point sum of the two operands.</p>
2974
2975<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2976<pre>
2977 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2978</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2979
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2980</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2981
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2982<!-- _______________________________________________________________________ -->
2983<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2984 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2985</div>
2986
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2987<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2988
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2989<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2990<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2991 &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]2992 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2993 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2994 &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]2995</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2996
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2997<h5>Overview:</h5>
2998<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2999 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3000
3001<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3002 '<tt>neg</tt>' instruction present in most other intermediate
3003 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3004
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3005<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3006<p>The two arguments to the '<tt>sub</tt>' instruction must
3007 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3008 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3009
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3010<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3011<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3012
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3013<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3014 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3015 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3016
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3017<p>Because LLVM integers use a two's complement representation, this instruction
3018 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3019
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3020<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3021 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3022 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
3023 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3024
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3025<h5>Example:</h5>
3026<pre>
3027 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
3028 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
3029</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3030
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3031</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3032
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3033<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3034<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3035 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3036</div>
3037
3038<div class="doc_text">
3039
3040<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3041<pre>
3042 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3043</pre>
3044
3045<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3046<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3047 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3048
3049<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3050 '<tt>fneg</tt>' instruction present in most other intermediate
3051 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3052
3053<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]3054<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3055 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3056 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3057
3058<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3059<p>The value produced is the floating point difference of the two operands.</p>
3060
3061<h5>Example:</h5>
3062<pre>
3063 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3064 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3065</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3066
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3067</div>
3068
3069<!-- _______________________________________________________________________ -->
3070<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3071 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3072</div>
3073
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3074<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3075
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3076<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3077<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3078 &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]3079 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3080 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3081 &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]3082</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3083
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3084<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3085<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3086
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3087<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3088<p>The two arguments to the '<tt>mul</tt>' instruction must
3089 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3090 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3091
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3092<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3093<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3094
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3095<p>If the result of the multiplication has unsigned overflow, the result
3096 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3097 width of the result.</p>
3098
3099<p>Because LLVM integers use a two's complement representation, and the result
3100 is the same width as the operands, this instruction returns the correct
3101 result for both signed and unsigned integers. If a full product
3102 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3103 be sign-extended or zero-extended as appropriate to the width of the full
3104 product.</p>
3105
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3106<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3107 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3108 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3109 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3110
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3111<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3112<pre>
3113 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3114</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3115
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3116</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3117
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3118<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3119<div class="doc_subsubsection">
3120 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3121</div>
3122
3123<div class="doc_text">
3124
3125<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3126<pre>
3127 &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]3128</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3129
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3130<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3131<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3132
3133<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3134<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3135 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3136 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3137
3138<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3139<p>The value produced is the floating point product of the two operands.</p>
3140
3141<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3142<pre>
3143 &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]3144</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3145
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3146</div>
3147
3148<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3149<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3150</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3151
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3152<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3153
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3154<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3155<pre>
3156 &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]3157</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3158
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3159<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3160<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3161
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3162<h5>Arguments:</h5>
3163<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3164 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3165 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3166
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3167<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3168<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3169
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3170<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3171 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3172
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3173<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3174
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3175<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3176<pre>
3177 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3178</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3179
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3180</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3181
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3182<!-- _______________________________________________________________________ -->
3183<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3184</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3185
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3186<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3187
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3188<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3189<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3190 &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]3191 &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]3192</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3193
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3194<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3195<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3196
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3197<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3198<p>The two arguments to the '<tt>sdiv</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>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3203<p>The value produced is the signed integer quotient of the two operands rounded
3204 towards zero.</p>
3205
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3206<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3207 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3208
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3209<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3210 undefined behavior; this is a rare case, but can occur, for example, by doing
3211 a 32-bit division of -2147483648 by -1.</p>
3212
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3213<p>If the <tt>exact</tt> keyword is present, the result value of the
3214 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3215 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3216
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3217<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3218<pre>
3219 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3220</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3221
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3222</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3223
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3224<!-- _______________________________________________________________________ -->
3225<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3226Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3228<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3229
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3230<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3231<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3232 &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]3233</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3234
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3235<h5>Overview:</h5>
3236<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3238<h5>Arguments:</h5>
3239<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3240 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3241 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3242
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3243<h5>Semantics:</h5>
3244<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3245
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3246<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3247<pre>
3248 &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]3249</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3250
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3251</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3252
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3253<!-- _______________________________________________________________________ -->
3254<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3255</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3256
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3257<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3258
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3259<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3260<pre>
3261 &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]3262</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3263
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3264<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3265<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3266 division of its two arguments.</p>
3267
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3268<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3269<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3270 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3271 values. Both arguments must have identical types.</p>
3272
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3273<h5>Semantics:</h5>
3274<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3275 This instruction always performs an unsigned division to get the
3276 remainder.</p>
3277
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3278<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3279 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3280
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3281<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3282
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3283<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3284<pre>
3285 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3286</pre>
3287
3288</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3289
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3290<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3291<div class="doc_subsubsection">
3292 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3293</div>
3294
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3295<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3296
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3297<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3298<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3299 &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]3300</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3301
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3302<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3303<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3304 division of its two operands. This instruction can also take
3305 <a href="#t_vector">vector</a> versions of the values in which case the
3306 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3307
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3308<h5>Arguments:</h5>
3309<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3310 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3311 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3312
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3313<h5>Semantics:</h5>
3314<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3315 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3316 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3317 a value. For more information about the difference,
3318 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3319 Math Forum</a>. For a table of how this is implemented in various languages,
3320 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3321 Wikipedia: modulo operation</a>.</p>
3322
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3323<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3324 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3325
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3326<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3327 Overflow also leads to undefined behavior; this is a rare case, but can
3328 occur, for example, by taking the remainder of a 32-bit division of
3329 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3330 lets srem be implemented using instructions that return both the result of
3331 the division and the remainder.)</p>
3332
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3333<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3334<pre>
3335 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3336</pre>
3337
3338</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3339
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3340<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3341<div class="doc_subsubsection">
3342 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3343
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3344<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3345
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3346<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3347<pre>
3348 &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]3349</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3350
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3351<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3352<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3353 its two operands.</p>
3354
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3355<h5>Arguments:</h5>
3356<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3357 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3358 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3359
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3360<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3361<p>This instruction returns the <i>remainder</i> of a division. The remainder
3362 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3363
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3364<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3365<pre>
3366 &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]3367</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3368
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3369</div>
3370
3371<!-- ======================================================================= -->
3372<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3373Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3374
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3375<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3376
3377<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3378 program. They are generally very efficient instructions and can commonly be
3379 strength reduced from other instructions. They require two operands of the
3380 same type, execute an operation on them, and produce a single value. The
3381 resulting value is the same type as its operands.</p>
3382
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3383</div>
3384
3385<!-- _______________________________________________________________________ -->
3386<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3387Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3388
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3389<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3390
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3391<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3392<pre>
3393 &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]3394</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3395
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3396<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3397<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3398 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3399
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3400<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3401<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3402 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3403 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3404
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3405<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3406<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3407 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3408 is (statically or dynamically) negative or equal to or larger than the number
3409 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3410 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3411 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3412
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3413<h5>Example:</h5>
3414<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3415 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3416 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3417 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3418 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3419 &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]3420</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3421
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3422</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3423
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3424<!-- _______________________________________________________________________ -->
3425<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3426Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3427
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3428<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3429
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3430<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3431<pre>
3432 &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]3433</pre>
3434
3435<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3436<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3437 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3438
3439<h5>Arguments:</h5>
3440<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3441 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3442 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3443
3444<h5>Semantics:</h5>
3445<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3446 significant bits of the result will be filled with zero bits after the shift.
3447 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3448 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3449 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3450 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3451
3452<h5>Example:</h5>
3453<pre>
3454 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3455 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3456 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3457 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3458 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3459 &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]3460</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3461
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3462</div>
3463
3464<!-- _______________________________________________________________________ -->
3465<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3466Instruction</a> </div>
3467<div class="doc_text">
3468
3469<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3470<pre>
3471 &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]3472</pre>
3473
3474<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3475<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3476 operand shifted to the right a specified number of bits with sign
3477 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3478
3479<h5>Arguments:</h5>
3480<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3481 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3482 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3483
3484<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3485<p>This instruction always performs an arithmetic shift right operation, The
3486 most significant bits of the result will be filled with the sign bit
3487 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3488 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3489 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3490 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3491
3492<h5>Example:</h5>
3493<pre>
3494 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3495 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3496 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3497 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3498 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3499 &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]3500</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3501
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3502</div>
3503
3504<!-- _______________________________________________________________________ -->
3505<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3506Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3507
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3508<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3509
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3510<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3511<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3512 &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]3513</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3514
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3515<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3516<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3517 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3518
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3519<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3520<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3521 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3522 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3524<h5>Semantics:</h5>
3525<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3526
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3527<table border="1" cellspacing="0" cellpadding="4">
3528 <tbody>
3529 <tr>
3530 <td>In0</td>
3531 <td>In1</td>
3532 <td>Out</td>
3533 </tr>
3534 <tr>
3535 <td>0</td>
3536 <td>0</td>
3537 <td>0</td>
3538 </tr>
3539 <tr>
3540 <td>0</td>
3541 <td>1</td>
3542 <td>0</td>
3543 </tr>
3544 <tr>
3545 <td>1</td>
3546 <td>0</td>
3547 <td>0</td>
3548 </tr>
3549 <tr>
3550 <td>1</td>
3551 <td>1</td>
3552 <td>1</td>
3553 </tr>
3554 </tbody>
3555</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3556
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3557<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3558<pre>
3559 &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]3560 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3561 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3562</pre>
3563</div>
3564<!-- _______________________________________________________________________ -->
3565<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3566
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3567<div class="doc_text">
3568
3569<h5>Syntax:</h5>
3570<pre>
3571 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3572</pre>
3573
3574<h5>Overview:</h5>
3575<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3576 two operands.</p>
3577
3578<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3579<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3580 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3581 values. Both arguments must have identical types.</p>
3582
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3583<h5>Semantics:</h5>
3584<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3585
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3586<table border="1" cellspacing="0" cellpadding="4">
3587 <tbody>
3588 <tr>
3589 <td>In0</td>
3590 <td>In1</td>
3591 <td>Out</td>
3592 </tr>
3593 <tr>
3594 <td>0</td>
3595 <td>0</td>
3596 <td>0</td>
3597 </tr>
3598 <tr>
3599 <td>0</td>
3600 <td>1</td>
3601 <td>1</td>
3602 </tr>
3603 <tr>
3604 <td>1</td>
3605 <td>0</td>
3606 <td>1</td>
3607 </tr>
3608 <tr>
3609 <td>1</td>
3610 <td>1</td>
3611 <td>1</td>
3612 </tr>
3613 </tbody>
3614</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3615
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3616<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3617<pre>
3618 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3619 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3620 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3621</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3622
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3623</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3624
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3625<!-- _______________________________________________________________________ -->
3626<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3627Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3628
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3629<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3630
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3631<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3632<pre>
3633 &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]3634</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3635
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3636<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3637<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3638 its two operands. The <tt>xor</tt> is used to implement the "one's
3639 complement" operation, which is the "~" operator in C.</p>
3640
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3641<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3642<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3643 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3644 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3645
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3646<h5>Semantics:</h5>
3647<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3648
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3649<table border="1" cellspacing="0" cellpadding="4">
3650 <tbody>
3651 <tr>
3652 <td>In0</td>
3653 <td>In1</td>
3654 <td>Out</td>
3655 </tr>
3656 <tr>
3657 <td>0</td>
3658 <td>0</td>
3659 <td>0</td>
3660 </tr>
3661 <tr>
3662 <td>0</td>
3663 <td>1</td>
3664 <td>1</td>
3665 </tr>
3666 <tr>
3667 <td>1</td>
3668 <td>0</td>
3669 <td>1</td>
3670 </tr>
3671 <tr>
3672 <td>1</td>
3673 <td>1</td>
3674 <td>0</td>
3675 </tr>
3676 </tbody>
3677</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3678
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3679<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3680<pre>
3681 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3682 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3683 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3684 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3685</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3686
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3687</div>
3688
3689<!-- ======================================================================= -->
3690<div class="doc_subsection">
3691 <a name="vectorops">Vector Operations</a>
3692</div>
3693
3694<div class="doc_text">
3695
3696<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3697 target-independent manner. These instructions cover the element-access and
3698 vector-specific operations needed to process vectors effectively. While LLVM
3699 does directly support these vector operations, many sophisticated algorithms
3700 will want to use target-specific intrinsics to take full advantage of a
3701 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3702
3703</div>
3704
3705<!-- _______________________________________________________________________ -->
3706<div class="doc_subsubsection">
3707 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3708</div>
3709
3710<div class="doc_text">
3711
3712<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3713<pre>
3714 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3715</pre>
3716
3717<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3718<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3719 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3720
3721
3722<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3723<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3724 of <a href="#t_vector">vector</a> type. The second operand is an index
3725 indicating the position from which to extract the element. The index may be
3726 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3727
3728<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3729<p>The result is a scalar of the same type as the element type of
3730 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3731 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3732 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3733
3734<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3735<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3736 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3737</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3738
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3739</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3740
3741<!-- _______________________________________________________________________ -->
3742<div class="doc_subsubsection">
3743 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3744</div>
3745
3746<div class="doc_text">
3747
3748<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3749<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3750 &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]3751</pre>
3752
3753<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3754<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3755 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3756
3757<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3758<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3759 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3760 whose type must equal the element type of the first operand. The third
3761 operand is an index indicating the position at which to insert the value.
3762 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3763
3764<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3765<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3766 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3767 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3768 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3769
3770<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3771<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3772 &lt;result&gt; = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3773</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3774
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3775</div>
3776
3777<!-- _______________________________________________________________________ -->
3778<div class="doc_subsubsection">
3779 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3780</div>
3781
3782<div class="doc_text">
3783
3784<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3785<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3786 &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]3787</pre>
3788
3789<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3790<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3791 from two input vectors, returning a vector with the same element type as the
3792 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3793
3794<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3795<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3796 with types that match each other. The third argument is a shuffle mask whose
3797 element type is always 'i32'. The result of the instruction is a vector
3798 whose length is the same as the shuffle mask and whose element type is the
3799 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3800
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3801<p>The shuffle mask operand is required to be a constant vector with either
3802 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3803
3804<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3805<p>The elements of the two input vectors are numbered from left to right across
3806 both of the vectors. The shuffle mask operand specifies, for each element of
3807 the result vector, which element of the two input vectors the result element
3808 gets. The element selector may be undef (meaning "don't care") and the
3809 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3810
3811<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3812<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3813 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3814 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3815 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3816 &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.
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3817 &lt;result&gt; = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3818 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3819 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3820 &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]3821</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3822
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3823</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3824
3825<!-- ======================================================================= -->
3826<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3827 <a name="aggregateops">Aggregate Operations</a>
3828</div>
3829
3830<div class="doc_text">
3831
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3832<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3833
3834</div>
3835
3836<!-- _______________________________________________________________________ -->
3837<div class="doc_subsubsection">
3838 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3839</div>
3840
3841<div class="doc_text">
3842
3843<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3844<pre>
3845 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3846</pre>
3847
3848<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3849<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3850 or array element from an aggregate value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3851
3852<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3853<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3854 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3855 operands are constant indices to specify which value to extract in a similar
3856 manner as indices in a
3857 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3858
3859<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3860<p>The result is the value at the position in the aggregate specified by the
3861 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3862
3863<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3864<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3865 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3866</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3867
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3868</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3869
3870<!-- _______________________________________________________________________ -->
3871<div class="doc_subsubsection">
3872 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3873</div>
3874
3875<div class="doc_text">
3876
3877<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3878<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3879 &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]3880</pre>
3881
3882<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3883<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3884 array element in an aggregate.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3885
3886
3887<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3888<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3889 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3890 second operand is a first-class value to insert. The following operands are
3891 constant indices indicating the position at which to insert the value in a
3892 similar manner as indices in a
3893 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3894 value to insert must have the same type as the value identified by the
3895 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3896
3897<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3898<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3899 that of <tt>val</tt> except that the value at the position specified by the
3900 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3901
3902<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3903<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3904 &lt;result&gt; = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3905</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3906
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3907</div>
3908
3909
3910<!-- ======================================================================= -->
3911<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3912 <a name="memoryops">Memory Access and Addressing Operations</a>
3913</div>
3914
3915<div class="doc_text">
3916
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3917<p>A key design point of an SSA-based representation is how it represents
3918 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]3919 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3920 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3921
3922</div>
3923
3924<!-- _______________________________________________________________________ -->
3925<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3926 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3927</div>
3928
3929<div class="doc_text">
3930
3931<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3932<pre>
3933 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3934</pre>
3935
3936<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3937<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3938 currently executing function, to be automatically released when this function
3939 returns to its caller. The object is always allocated in the generic address
3940 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3941
3942<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3943<p>The '<tt>alloca</tt>' instruction
3944 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3945 runtime stack, returning a pointer of the appropriate type to the program.
3946 If "NumElements" is specified, it is the number of elements allocated,
3947 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3948 specified, the value result of the allocation is guaranteed to be aligned to
3949 at least that boundary. If not specified, or if zero, the target can choose
3950 to align the allocation on any convenient boundary compatible with the
3951 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3952
3953<p>'<tt>type</tt>' may be any sized type.</p>
3954
3955<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3956<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3957 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3958 memory is automatically released when the function returns. The
3959 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3960 variables that must have an address available. When the function returns
3961 (either with the <tt><a href="#i_ret">ret</a></tt>
3962 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3963 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3964
3965<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3966<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3967 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3968 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3969 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3970 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3971</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3972
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3973</div>
3974
3975<!-- _______________________________________________________________________ -->
3976<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3977Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3978
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3979<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3980
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3981<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3982<pre>
3983 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3984 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3985</pre>
3986
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3987<h5>Overview:</h5>
3988<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3989
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3990<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3991<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3992 from which to load. The pointer must point to
3993 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3994 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3995 number or order of execution of this <tt>load</tt> with other
3996 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3997 instructions. </p>
3998
3999<p>The optional constant "align" argument specifies the alignment of the
4000 operation (that is, the alignment of the memory address). A value of 0 or an
4001 omitted "align" argument means that the operation has the preferential
4002 alignment for the target. It is the responsibility of the code emitter to
4003 ensure that the alignment information is correct. Overestimating the
4004 alignment results in an undefined behavior. Underestimating the alignment may
4005 produce less efficient code. An alignment of 1 is always safe.</p>
4006
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4007<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4008<p>The location of memory pointed to is loaded. If the value being loaded is of
4009 scalar type then the number of bytes read does not exceed the minimum number
4010 of bytes needed to hold all bits of the type. For example, loading an
4011 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4012 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4013 is undefined if the value was not originally written using a store of the
4014 same type.</p>
4015
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4016<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4017<pre>
4018 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4019 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4020 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
4021</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4022
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4023</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4024
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4025<!-- _______________________________________________________________________ -->
4026<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4027Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4028
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4029<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4030
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4031<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4032<pre>
4033 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]4034 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
4035</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4036
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4037<h5>Overview:</h5>
4038<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4039
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4040<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4041<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4042 and an address at which to store it. The type of the
4043 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4044 the <a href="#t_firstclass">first class</a> type of the
4045 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4046 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4047 or order of execution of this <tt>store</tt> with other
4048 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4049 instructions.</p>
4050
4051<p>The optional constant "align" argument specifies the alignment of the
4052 operation (that is, the alignment of the memory address). A value of 0 or an
4053 omitted "align" argument means that the operation has the preferential
4054 alignment for the target. It is the responsibility of the code emitter to
4055 ensure that the alignment information is correct. Overestimating the
4056 alignment results in an undefined behavior. Underestimating the alignment may
4057 produce less efficient code. An alignment of 1 is always safe.</p>
4058
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4059<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4060<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4061 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4062 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4063 does not exceed the minimum number of bytes needed to hold all bits of the
4064 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4065 writing a value of a type like <tt>i20</tt> with a size that is not an
4066 integral number of bytes, it is unspecified what happens to the extra bits
4067 that do not belong to the type, but they will typically be overwritten.</p>
4068
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4069<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4070<pre>
4071 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4072 store i32 3, i32* %ptr <i>; yields {void}</i>
4073 %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]4074</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4075
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4076</div>
4077
4078<!-- _______________________________________________________________________ -->
4079<div class="doc_subsubsection">
4080 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4081</div>
4082
4083<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4084
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4085<h5>Syntax:</h5>
4086<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4087 &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]4088 &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]4089</pre>
4090
4091<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4092<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4093 subelement of an aggregate data structure. It performs address calculation
4094 only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4095
4096<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4097<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4098 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4099 elements of the aggregate object are indexed. The interpretation of each
4100 index is dependent on the type being indexed into. The first index always
4101 indexes the pointer value given as the first argument, the second index
4102 indexes a value of the type pointed to (not necessarily the value directly
4103 pointed to, since the first index can be non-zero), etc. The first type
4104 indexed into must be a pointer value, subsequent types can be arrays, vectors
4105 and structs. Note that subsequent types being indexed into can never be
4106 pointers, since that would require loading the pointer before continuing
4107 calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4108
4109<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]4110 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4111 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4112 vector, integers of any width are allowed, and they are not required to be
4113 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4114
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4115<p>For example, let's consider a C code fragment and how it gets compiled to
4116 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4117
4118<div class="doc_code">
4119<pre>
4120struct RT {
4121 char A;
4122 int B[10][20];
4123 char C;
4124};
4125struct ST {
4126 int X;
4127 double Y;
4128 struct RT Z;
4129};
4130
4131int *foo(struct ST *s) {
4132 return &amp;s[1].Z.B[5][13];
4133}
4134</pre>
4135</div>
4136
4137<p>The LLVM code generated by the GCC frontend is:</p>
4138
4139<div class="doc_code">
4140<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4141%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4142%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4143
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4144define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4145entry:
4146 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4147 ret i32* %reg
4148}
4149</pre>
4150</div>
4151
4152<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4153<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]4154 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4155 }</tt>' type, a structure. The second index indexes into the third element
4156 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4157 i8 }</tt>' type, another structure. The third index indexes into the second
4158 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4159 array. The two dimensions of the array are subscripted into, yielding an
4160 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4161 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4162
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4163<p>Note that it is perfectly legal to index partially through a structure,
4164 returning a pointer to an inner element. Because of this, the LLVM code for
4165 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4166
4167<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4168 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4169 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4170 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4171 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4172 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4173 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4174 ret i32* %t5
4175 }
4176</pre>
4177
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4178<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4179 <tt>getelementptr</tt> is undefined if the base pointer is not an
4180 <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]4181 that would be formed by successive addition of the offsets implied by the
4182 indices to the base address with infinitely precise arithmetic are not an
4183 <i>in bounds</i> address of that allocated object.
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4184 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4185 that point into the object, plus the address one byte past the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4186
4187<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4188 the base address with silently-wrapping two's complement arithmetic, and
4189 the result value of the <tt>getelementptr</tt> may be outside the object
4190 pointed to by the base pointer. The result value may not necessarily be
4191 used to access memory though, even if it happens to point into allocated
4192 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4193 section for more information.</p>
4194
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4195<p>The getelementptr instruction is often confusing. For some more insight into
4196 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4197
4198<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4199<pre>
4200 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4201 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4202 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4203 %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]4204 <i>; yields i8*:eptr</i>
4205 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4206 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4207 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4208</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4209
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4210</div>
4211
4212<!-- ======================================================================= -->
4213<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4214</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4215
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4216<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4217
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4218<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4219 which all take a single operand and a type. They perform various bit
4220 conversions on the operand.</p>
4221
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4222</div>
4223
4224<!-- _______________________________________________________________________ -->
4225<div class="doc_subsubsection">
4226 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4227</div>
4228<div class="doc_text">
4229
4230<h5>Syntax:</h5>
4231<pre>
4232 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4233</pre>
4234
4235<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4236<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4237 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4238
4239<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4240<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4241 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4242 size and type of the result, which must be
4243 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4244 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4245 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4246
4247<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4248<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4249 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4250 source size must be larger than the destination size, <tt>trunc</tt> cannot
4251 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4252
4253<h5>Example:</h5>
4254<pre>
4255 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4256 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4257 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4258</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4259
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4260</div>
4261
4262<!-- _______________________________________________________________________ -->
4263<div class="doc_subsubsection">
4264 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4265</div>
4266<div class="doc_text">
4267
4268<h5>Syntax:</h5>
4269<pre>
4270 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4271</pre>
4272
4273<h5>Overview:</h5>
4274<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4275 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4276
4277
4278<h5>Arguments:</h5>
4279<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]4280 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4281 also be of <a href="#t_integer">integer</a> type. The bit size of the
4282 <tt>value</tt> must be smaller than the bit size of the destination type,
4283 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4284
4285<h5>Semantics:</h5>
4286<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]4287 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4288
4289<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4290
4291<h5>Example:</h5>
4292<pre>
4293 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4294 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4295</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4296
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4297</div>
4298
4299<!-- _______________________________________________________________________ -->
4300<div class="doc_subsubsection">
4301 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4302</div>
4303<div class="doc_text">
4304
4305<h5>Syntax:</h5>
4306<pre>
4307 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4308</pre>
4309
4310<h5>Overview:</h5>
4311<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4312
4313<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4314<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4315 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4316 also be of <a href="#t_integer">integer</a> type. The bit size of the
4317 <tt>value</tt> must be smaller than the bit size of the destination type,
4318 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4319
4320<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4321<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4322 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4323 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4324
4325<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4326
4327<h5>Example:</h5>
4328<pre>
4329 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4330 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4331</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4332
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4333</div>
4334
4335<!-- _______________________________________________________________________ -->
4336<div class="doc_subsubsection">
4337 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4338</div>
4339
4340<div class="doc_text">
4341
4342<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4343<pre>
4344 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4345</pre>
4346
4347<h5>Overview:</h5>
4348<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4349 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4350
4351<h5>Arguments:</h5>
4352<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4353 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4354 to cast it to. The size of <tt>value</tt> must be larger than the size of
4355 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4356 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4357
4358<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4359<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4360 <a href="#t_floating">floating point</a> type to a smaller
4361 <a href="#t_floating">floating point</a> type. If the value cannot fit
4362 within the destination type, <tt>ty2</tt>, then the results are
4363 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4364
4365<h5>Example:</h5>
4366<pre>
4367 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4368 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4369</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4370
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4371</div>
4372
4373<!-- _______________________________________________________________________ -->
4374<div class="doc_subsubsection">
4375 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4376</div>
4377<div class="doc_text">
4378
4379<h5>Syntax:</h5>
4380<pre>
4381 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4382</pre>
4383
4384<h5>Overview:</h5>
4385<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]4386 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4387
4388<h5>Arguments:</h5>
4389<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4390 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4391 a <a href="#t_floating">floating point</a> type to cast it to. The source
4392 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4393
4394<h5>Semantics:</h5>
4395<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4396 <a href="#t_floating">floating point</a> type to a larger
4397 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4398 used to make a <i>no-op cast</i> because it always changes bits. Use
4399 <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]4400
4401<h5>Example:</h5>
4402<pre>
4403 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4404 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4405</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4406
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4407</div>
4408
4409<!-- _______________________________________________________________________ -->
4410<div class="doc_subsubsection">
4411 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4412</div>
4413<div class="doc_text">
4414
4415<h5>Syntax:</h5>
4416<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4417 &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]4418</pre>
4419
4420<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4421<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4422 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4423
4424<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4425<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4426 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4427 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4428 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4429 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4430
4431<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4432<p>The '<tt>fptoui</tt>' instruction converts its
4433 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4434 towards zero) unsigned integer value. If the value cannot fit
4435 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4436
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4437<h5>Example:</h5>
4438<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4439 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4440 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4441 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4442</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4443
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4444</div>
4445
4446<!-- _______________________________________________________________________ -->
4447<div class="doc_subsubsection">
4448 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4449</div>
4450<div class="doc_text">
4451
4452<h5>Syntax:</h5>
4453<pre>
4454 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4455</pre>
4456
4457<h5>Overview:</h5>
4458<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4459 <a href="#t_floating">floating point</a> <tt>value</tt> to
4460 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4461
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4462<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4463<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4464 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4465 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4466 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4467 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4468
4469<h5>Semantics:</h5>
4470<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4471 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4472 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4473 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4474
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4475<h5>Example:</h5>
4476<pre>
4477 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4478 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4479 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4480</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4481
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4482</div>
4483
4484<!-- _______________________________________________________________________ -->
4485<div class="doc_subsubsection">
4486 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4487</div>
4488<div class="doc_text">
4489
4490<h5>Syntax:</h5>
4491<pre>
4492 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4493</pre>
4494
4495<h5>Overview:</h5>
4496<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4497 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4498
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4499<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4500<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]4501 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4502 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4503 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4504 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4505
4506<h5>Semantics:</h5>
4507<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4508 integer quantity and converts it to the corresponding floating point
4509 value. If the value cannot fit in the floating point value, the results are
4510 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4511
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4512<h5>Example:</h5>
4513<pre>
4514 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4515 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4516</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4517
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4518</div>
4519
4520<!-- _______________________________________________________________________ -->
4521<div class="doc_subsubsection">
4522 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4523</div>
4524<div class="doc_text">
4525
4526<h5>Syntax:</h5>
4527<pre>
4528 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4529</pre>
4530
4531<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4532<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4533 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4534
4535<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4536<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]4537 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4538 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4539 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4540 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4541
4542<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4543<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4544 quantity and converts it to the corresponding floating point value. If the
4545 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4546
4547<h5>Example:</h5>
4548<pre>
4549 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4550 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4551</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4552
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4553</div>
4554
4555<!-- _______________________________________________________________________ -->
4556<div class="doc_subsubsection">
4557 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4558</div>
4559<div class="doc_text">
4560
4561<h5>Syntax:</h5>
4562<pre>
4563 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4564</pre>
4565
4566<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4567<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4568 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4569
4570<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4571<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4572 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4573 <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]4574
4575<h5>Semantics:</h5>
4576<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4577 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4578 truncating or zero extending that value to the size of the integer type. If
4579 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4580 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4581 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4582 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4583
4584<h5>Example:</h5>
4585<pre>
4586 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4587 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4588</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4590</div>
4591
4592<!-- _______________________________________________________________________ -->
4593<div class="doc_subsubsection">
4594 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4595</div>
4596<div class="doc_text">
4597
4598<h5>Syntax:</h5>
4599<pre>
4600 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4601</pre>
4602
4603<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4604<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4605 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4606
4607<h5>Arguments:</h5>
4608<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4609 value to cast, and a type to cast it to, which must be a
4610 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4611
4612<h5>Semantics:</h5>
4613<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4614 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4615 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4616 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4617 than the size of a pointer then a zero extension is done. If they are the
4618 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4619
4620<h5>Example:</h5>
4621<pre>
4622 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4623 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4624 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4625</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4626
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4627</div>
4628
4629<!-- _______________________________________________________________________ -->
4630<div class="doc_subsubsection">
4631 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4632</div>
4633<div class="doc_text">
4634
4635<h5>Syntax:</h5>
4636<pre>
4637 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4638</pre>
4639
4640<h5>Overview:</h5>
4641<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4642 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4643
4644<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4645<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4646 non-aggregate first class value, and a type to cast it to, which must also be
4647 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4648 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4649 identical. If the source type is a pointer, the destination type must also be
4650 a pointer. This instruction supports bitwise conversion of vectors to
4651 integers and to vectors of other types (as long as they have the same
4652 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4653
4654<h5>Semantics:</h5>
4655<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4656 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4657 this conversion. The conversion is done as if the <tt>value</tt> had been
4658 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4659 be converted to other pointer types with this instruction. To convert
4660 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4661 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4662
4663<h5>Example:</h5>
4664<pre>
4665 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4666 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4667 %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]4668</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4669
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4670</div>
4671
4672<!-- ======================================================================= -->
4673<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4674
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4675<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4676
4677<p>The instructions in this category are the "miscellaneous" instructions, which
4678 defy better classification.</p>
4679
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4680</div>
4681
4682<!-- _______________________________________________________________________ -->
4683<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4684</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4685
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4686<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4687
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4688<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4689<pre>
4690 &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]4691</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4692
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4693<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4694<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4695 boolean values based on comparison of its two integer, integer vector, or
4696 pointer operands.</p>
4697
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4698<h5>Arguments:</h5>
4699<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4700 the condition code indicating the kind of comparison to perform. It is not a
4701 value, just a keyword. The possible condition code are:</p>
4702
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4703<ol>
4704 <li><tt>eq</tt>: equal</li>
4705 <li><tt>ne</tt>: not equal </li>
4706 <li><tt>ugt</tt>: unsigned greater than</li>
4707 <li><tt>uge</tt>: unsigned greater or equal</li>
4708 <li><tt>ult</tt>: unsigned less than</li>
4709 <li><tt>ule</tt>: unsigned less or equal</li>
4710 <li><tt>sgt</tt>: signed greater than</li>
4711 <li><tt>sge</tt>: signed greater or equal</li>
4712 <li><tt>slt</tt>: signed less than</li>
4713 <li><tt>sle</tt>: signed less or equal</li>
4714</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4715
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4716<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4717 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4718 typed. They must also be identical types.</p>
4719
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4720<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4721<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4722 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4723 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4724 result, as follows:</p>
4725
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4726<ol>
4727 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4728 <tt>false</tt> otherwise. No sign interpretation is necessary or
4729 performed.</li>
4730
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4731 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4732 <tt>false</tt> otherwise. No sign interpretation is necessary or
4733 performed.</li>
4734
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4735 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4736 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4737
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4738 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4739 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4740 to <tt>op2</tt>.</li>
4741
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4742 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4743 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4744
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4745 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4746 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4747
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4748 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4749 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4750
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4751 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4752 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4753 to <tt>op2</tt>.</li>
4754
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4755 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4756 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4757
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4758 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4759 <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]4760</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4761
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4762<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4763 values are compared as if they were integers.</p>
4764
4765<p>If the operands are integer vectors, then they are compared element by
4766 element. The result is an <tt>i1</tt> vector with the same number of elements
4767 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4768
4769<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4770<pre>
4771 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4772 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4773 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4774 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4775 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4776 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4777</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4778
4779<p>Note that the code generator does not yet support vector types with
4780 the <tt>icmp</tt> instruction.</p>
4781
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4782</div>
4783
4784<!-- _______________________________________________________________________ -->
4785<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4786</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4787
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4788<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4789
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4790<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4791<pre>
4792 &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]4793</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4794
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4795<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4796<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4797 values based on comparison of its operands.</p>
4798
4799<p>If the operands are floating point scalars, then the result type is a boolean
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4800(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4801
4802<p>If the operands are floating point vectors, then the result type is a vector
4803 of boolean with the same number of elements as the operands being
4804 compared.</p>
4805
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4806<h5>Arguments:</h5>
4807<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4808 the condition code indicating the kind of comparison to perform. It is not a
4809 value, just a keyword. The possible condition code are:</p>
4810
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4811<ol>
4812 <li><tt>false</tt>: no comparison, always returns false</li>
4813 <li><tt>oeq</tt>: ordered and equal</li>
4814 <li><tt>ogt</tt>: ordered and greater than </li>
4815 <li><tt>oge</tt>: ordered and greater than or equal</li>
4816 <li><tt>olt</tt>: ordered and less than </li>
4817 <li><tt>ole</tt>: ordered and less than or equal</li>
4818 <li><tt>one</tt>: ordered and not equal</li>
4819 <li><tt>ord</tt>: ordered (no nans)</li>
4820 <li><tt>ueq</tt>: unordered or equal</li>
4821 <li><tt>ugt</tt>: unordered or greater than </li>
4822 <li><tt>uge</tt>: unordered or greater than or equal</li>
4823 <li><tt>ult</tt>: unordered or less than </li>
4824 <li><tt>ule</tt>: unordered or less than or equal</li>
4825 <li><tt>une</tt>: unordered or not equal</li>
4826 <li><tt>uno</tt>: unordered (either nans)</li>
4827 <li><tt>true</tt>: no comparison, always returns true</li>
4828</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4829
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4830<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4831 <i>unordered</i> means that either operand may be a QNAN.</p>
4832
4833<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4834 a <a href="#t_floating">floating point</a> type or
4835 a <a href="#t_vector">vector</a> of floating point type. They must have
4836 identical types.</p>
4837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4838<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4839<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4840 according to the condition code given as <tt>cond</tt>. If the operands are
4841 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4842 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4843 follows:</p>
4844
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4845<ol>
4846 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4847
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4848 <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]4849 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4850
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4851 <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]4852 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4853
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4854 <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]4855 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4856
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4857 <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]4858 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4859
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4860 <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]4861 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4862
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4863 <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]4864 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4865
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4866 <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]4867
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4868 <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]4869 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4870
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4871 <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]4872 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4873
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4874 <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]4875 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4876
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4877 <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]4878 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4879
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4880 <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]4881 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4882
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4883 <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]4884 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4885
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4886 <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]4887
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4888 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4889</ol>
4890
4891<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4892<pre>
4893 &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]4894 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4895 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4896 &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]4897</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4898
4899<p>Note that the code generator does not yet support vector types with
4900 the <tt>fcmp</tt> instruction.</p>
4901
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4902</div>
4903
4904<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4905<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4906 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4907</div>
4908
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4909<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4910
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4911<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4912<pre>
4913 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4914</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4915
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4916<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4917<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4918 SSA graph representing the function.</p>
4919
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4920<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4921<p>The type of the incoming values is specified with the first type field. After
4922 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4923 one pair for each predecessor basic block of the current block. Only values
4924 of <a href="#t_firstclass">first class</a> type may be used as the value
4925 arguments to the PHI node. Only labels may be used as the label
4926 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4927
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4928<p>There must be no non-phi instructions between the start of a basic block and
4929 the PHI instructions: i.e. PHI instructions must be first in a basic
4930 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4931
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4932<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4933 occur on the edge from the corresponding predecessor block to the current
4934 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4935 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4936
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4937<h5>Semantics:</h5>
4938<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4939 specified by the pair corresponding to the predecessor basic block that
4940 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4941
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4942<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4943<pre>
4944Loop: ; Infinite loop that counts from 0 on up...
4945 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4946 %nextindvar = add i32 %indvar, 1
4947 br label %Loop
4948</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4949
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4950</div>
4951
4952<!-- _______________________________________________________________________ -->
4953<div class="doc_subsubsection">
4954 <a name="i_select">'<tt>select</tt>' Instruction</a>
4955</div>
4956
4957<div class="doc_text">
4958
4959<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4960<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4961 &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>
4962
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4963 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4964</pre>
4965
4966<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4967<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4968 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4969
4970
4971<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4972<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4973 values indicating the condition, and two values of the
4974 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4975 vectors and the condition is a scalar, then entire vectors are selected, not
4976 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4977
4978<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4979<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4980 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4981
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4982<p>If the condition is a vector of i1, then the value arguments must be vectors
4983 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4984
4985<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4986<pre>
4987 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4988</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4989
4990<p>Note that the code generator does not yet support conditions
4991 with vector type.</p>
4992
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4993</div>
4994
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4995<!-- _______________________________________________________________________ -->
4996<div class="doc_subsubsection">
4997 <a name="i_call">'<tt>call</tt>' Instruction</a>
4998</div>
4999
5000<div class="doc_text">
5001
5002<h5>Syntax:</h5>
5003<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]5004 &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]5005</pre>
5006
5007<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5008<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
5009
5010<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5011<p>This instruction requires several arguments:</p>
5012
5013<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5014 <li>The optional "tail" marker indicates whether the callee function accesses
5015 any allocas or varargs in the caller. If the "tail" marker is present,
5016 the function call is eligible for tail call optimization. Note that calls
5017 may be marked "tail" even if they do not occur before
5018 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5019
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5020 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5021 convention</a> the call should use. If none is specified, the call
5022 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5023
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5024 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5025 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5026 '<tt>inreg</tt>' attributes are valid here.</li>
5027
5028 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5029 type of the return value. Functions that return no value are marked
5030 <tt><a href="#t_void">void</a></tt>.</li>
5031
5032 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5033 being invoked. The argument types must match the types implied by this
5034 signature. This type can be omitted if the function is not varargs and if
5035 the function type does not return a pointer to a function.</li>
5036
5037 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5038 be invoked. In most cases, this is a direct function invocation, but
5039 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5040 to function value.</li>
5041
5042 <li>'<tt>function args</tt>': argument list whose types match the function
5043 signature argument types. All arguments must be of
5044 <a href="#t_firstclass">first class</a> type. If the function signature
5045 indicates the function accepts a variable number of arguments, the extra
5046 arguments can be specified.</li>
5047
5048 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5049 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5050 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5051</ol>
5052
5053<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5054<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5055 a specified function, with its incoming arguments bound to the specified
5056 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5057 function, control flow continues with the instruction after the function
5058 call, and the return value of the function is bound to the result
5059 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5060
5061<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5062<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5063 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5064 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5065 %X = tail call i32 @foo() <i>; yields i32</i>
5066 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5067 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5068
5069 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5070 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5071 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5072 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5073 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5074 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5075</pre>
5076
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5077<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5078standard C99 library as being the C99 library functions, and may perform
5079optimizations or generate code for them under that assumption. This is
5080something we'd like to change in the future to provide better support for
5081freestanding environments and non-C-based langauges.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5082
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5083</div>
5084
5085<!-- _______________________________________________________________________ -->
5086<div class="doc_subsubsection">
5087 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5088</div>
5089
5090<div class="doc_text">
5091
5092<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5093<pre>
5094 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5095</pre>
5096
5097<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5098<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5099 the "variable argument" area of a function call. It is used to implement the
5100 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5101
5102<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5103<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5104 argument. It returns a value of the specified argument type and increments
5105 the <tt>va_list</tt> to point to the next argument. The actual type
5106 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5107
5108<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5109<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5110 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5111 to the next argument. For more information, see the variable argument
5112 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5113
5114<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]5115 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5116 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5117
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5118<p><tt>va_arg</tt> is an LLVM instruction instead of
5119 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5120 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5121
5122<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5123<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5124
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5125<p>Note that the code generator does not yet fully support va_arg on many
5126 targets. Also, it does not currently support va_arg with aggregate types on
5127 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5128
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5129</div>
5130
5131<!-- *********************************************************************** -->
5132<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5133<!-- *********************************************************************** -->
5134
5135<div class="doc_text">
5136
5137<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5138 well known names and semantics and are required to follow certain
5139 restrictions. Overall, these intrinsics represent an extension mechanism for
5140 the LLVM language that does not require changing all of the transformations
5141 in LLVM when adding to the language (or the bitcode reader/writer, the
5142 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5143
5144<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5145 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5146 begin with this prefix. Intrinsic functions must always be external
5147 functions: you cannot define the body of intrinsic functions. Intrinsic
5148 functions may only be used in call or invoke instructions: it is illegal to
5149 take the address of an intrinsic function. Additionally, because intrinsic
5150 functions are part of the LLVM language, it is required if any are added that
5151 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5152
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5153<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5154 family of functions that perform the same operation but on different data
5155 types. Because LLVM can represent over 8 million different integer types,
5156 overloading is used commonly to allow an intrinsic function to operate on any
5157 integer type. One or more of the argument types or the result type can be
5158 overloaded to accept any integer type. Argument types may also be defined as
5159 exactly matching a previous argument's type or the result type. This allows
5160 an intrinsic function which accepts multiple arguments, but needs all of them
5161 to be of the same type, to only be overloaded with respect to a single
5162 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5163
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5164<p>Overloaded intrinsics will have the names of its overloaded argument types
5165 encoded into its function name, each preceded by a period. Only those types
5166 which are overloaded result in a name suffix. Arguments whose type is matched
5167 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5168 can take an integer of any width and returns an integer of exactly the same
5169 integer width. This leads to a family of functions such as
5170 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5171 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5172 suffix is required. Because the argument's type is matched against the return
5173 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5174
5175<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5176 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5177
5178</div>
5179
5180<!-- ======================================================================= -->
5181<div class="doc_subsection">
5182 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5183</div>
5184
5185<div class="doc_text">
5186
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5187<p>Variable argument support is defined in LLVM with
5188 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5189 intrinsic functions. These functions are related to the similarly named
5190 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5191
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5192<p>All of these functions operate on arguments that use a target-specific value
5193 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5194 not define what this type is, so all transformations should be prepared to
5195 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5196
5197<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]5198 instruction and the variable argument handling intrinsic functions are
5199 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5200
5201<div class="doc_code">
5202<pre>
5203define i32 @test(i32 %X, ...) {
5204 ; Initialize variable argument processing
5205 %ap = alloca i8*
5206 %ap2 = bitcast i8** %ap to i8*
5207 call void @llvm.va_start(i8* %ap2)
5208
5209 ; Read a single integer argument
5210 %tmp = va_arg i8** %ap, i32
5211
5212 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5213 %aq = alloca i8*
5214 %aq2 = bitcast i8** %aq to i8*
5215 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5216 call void @llvm.va_end(i8* %aq2)
5217
5218 ; Stop processing of arguments.
5219 call void @llvm.va_end(i8* %ap2)
5220 ret i32 %tmp
5221}
5222
5223declare void @llvm.va_start(i8*)
5224declare void @llvm.va_copy(i8*, i8*)
5225declare void @llvm.va_end(i8*)
5226</pre>
5227</div>
5228
5229</div>
5230
5231<!-- _______________________________________________________________________ -->
5232<div class="doc_subsubsection">
5233 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5234</div>
5235
5236
5237<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5238
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5239<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5240<pre>
5241 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5242</pre>
5243
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5244<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5245<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5246 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]5247
5248<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5249<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]5250
5251<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5252<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]5253 macro available in C. In a target-dependent way, it initializes
5254 the <tt>va_list</tt> element to which the argument points, so that the next
5255 call to <tt>va_arg</tt> will produce the first variable argument passed to
5256 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5257 need to know the last argument of the function as the compiler can figure
5258 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5259
5260</div>
5261
5262<!-- _______________________________________________________________________ -->
5263<div class="doc_subsubsection">
5264 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5265</div>
5266
5267<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5268
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5269<h5>Syntax:</h5>
5270<pre>
5271 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5272</pre>
5273
5274<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5275<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5276 which has been initialized previously
5277 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5278 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5279
5280<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5281<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5282
5283<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5284<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]5285 macro available in C. In a target-dependent way, it destroys
5286 the <tt>va_list</tt> element to which the argument points. Calls
5287 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5288 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5289 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5290
5291</div>
5292
5293<!-- _______________________________________________________________________ -->
5294<div class="doc_subsubsection">
5295 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5296</div>
5297
5298<div class="doc_text">
5299
5300<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5301<pre>
5302 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5303</pre>
5304
5305<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5306<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5307 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5308
5309<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5310<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]5311 The second argument is a pointer to a <tt>va_list</tt> element to copy
5312 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5313
5314<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5315<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]5316 macro available in C. In a target-dependent way, it copies the
5317 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5318 element. This intrinsic is necessary because
5319 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5320 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5321
5322</div>
5323
5324<!-- ======================================================================= -->
5325<div class="doc_subsection">
5326 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5327</div>
5328
5329<div class="doc_text">
5330
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5331<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5332Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5333intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5334roots on the stack</a>, as well as garbage collector implementations that
5335require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5336barriers. Front-ends for type-safe garbage collected languages should generate
5337these intrinsics to make use of the LLVM garbage collectors. For more details,
5338see <a href="GarbageCollection.html">Accurate Garbage Collection with
5339LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5340
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5341<p>The garbage collection intrinsics only operate on objects in the generic
5342 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5343
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5344</div>
5345
5346<!-- _______________________________________________________________________ -->
5347<div class="doc_subsubsection">
5348 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5349</div>
5350
5351<div class="doc_text">
5352
5353<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5354<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5355 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5356</pre>
5357
5358<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5359<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]5360 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5361
5362<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5363<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5364 root pointer. The second pointer (which must be either a constant or a
5365 global value address) contains the meta-data to be associated with the
5366 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5367
5368<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5369<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]5370 location. At compile-time, the code generator generates information to allow
5371 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5372 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5373 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5374
5375</div>
5376
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5377<!-- _______________________________________________________________________ -->
5378<div class="doc_subsubsection">
5379 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5380</div>
5381
5382<div class="doc_text">
5383
5384<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5385<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5386 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5387</pre>
5388
5389<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5390<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5391 locations, allowing garbage collector implementations that require read
5392 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5393
5394<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5395<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]5396 allocated from the garbage collector. The first object is a pointer to the
5397 start of the referenced object, if needed by the language runtime (otherwise
5398 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5399
5400<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5401<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5402 instruction, but may be replaced with substantially more complex code by the
5403 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5404 may only be used in a function which <a href="#gc">specifies a GC
5405 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5406
5407</div>
5408
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5409<!-- _______________________________________________________________________ -->
5410<div class="doc_subsubsection">
5411 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5412</div>
5413
5414<div class="doc_text">
5415
5416<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5417<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5418 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5419</pre>
5420
5421<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5422<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5423 locations, allowing garbage collector implementations that require write
5424 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5425
5426<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5427<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]5428 object to store it to, and the third is the address of the field of Obj to
5429 store to. If the runtime does not require a pointer to the object, Obj may
5430 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5431
5432<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5433<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5434 instruction, but may be replaced with substantially more complex code by the
5435 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5436 may only be used in a function which <a href="#gc">specifies a GC
5437 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5438
5439</div>
5440
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5441<!-- ======================================================================= -->
5442<div class="doc_subsection">
5443 <a name="int_codegen">Code Generator Intrinsics</a>
5444</div>
5445
5446<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5447
5448<p>These intrinsics are provided by LLVM to expose special features that may
5449 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5450
5451</div>
5452
5453<!-- _______________________________________________________________________ -->
5454<div class="doc_subsubsection">
5455 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5456</div>
5457
5458<div class="doc_text">
5459
5460<h5>Syntax:</h5>
5461<pre>
5462 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5463</pre>
5464
5465<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5466<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5467 target-specific value indicating the return address of the current function
5468 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5469
5470<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5471<p>The argument to this intrinsic indicates which function to return the address
5472 for. Zero indicates the calling function, one indicates its caller, etc.
5473 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5474
5475<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5476<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5477 indicating the return address of the specified call frame, or zero if it
5478 cannot be identified. The value returned by this intrinsic is likely to be
5479 incorrect or 0 for arguments other than zero, so it should only be used for
5480 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5481
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5482<p>Note that calling this intrinsic does not prevent function inlining or other
5483 aggressive transformations, so the value returned may not be that of the
5484 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5485
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5486</div>
5487
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5488<!-- _______________________________________________________________________ -->
5489<div class="doc_subsubsection">
5490 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5491</div>
5492
5493<div class="doc_text">
5494
5495<h5>Syntax:</h5>
5496<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5497 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5498</pre>
5499
5500<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5501<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5502 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5503
5504<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5505<p>The argument to this intrinsic indicates which function to return the frame
5506 pointer for. Zero indicates the calling function, one indicates its caller,
5507 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5508
5509<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5510<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5511 indicating the frame address of the specified call frame, or zero if it
5512 cannot be identified. The value returned by this intrinsic is likely to be
5513 incorrect or 0 for arguments other than zero, so it should only be used for
5514 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5515
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5516<p>Note that calling this intrinsic does not prevent function inlining or other
5517 aggressive transformations, so the value returned may not be that of the
5518 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5519
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5520</div>
5521
5522<!-- _______________________________________________________________________ -->
5523<div class="doc_subsubsection">
5524 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5525</div>
5526
5527<div class="doc_text">
5528
5529<h5>Syntax:</h5>
5530<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5531 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5532</pre>
5533
5534<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5535<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5536 of the function stack, for use
5537 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5538 useful for implementing language features like scoped automatic variable
5539 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5540
5541<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5542<p>This intrinsic returns a opaque pointer value that can be passed
5543 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5544 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5545 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5546 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5547 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5548 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5549
5550</div>
5551
5552<!-- _______________________________________________________________________ -->
5553<div class="doc_subsubsection">
5554 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5555</div>
5556
5557<div class="doc_text">
5558
5559<h5>Syntax:</h5>
5560<pre>
5561 declare void @llvm.stackrestore(i8 * %ptr)
5562</pre>
5563
5564<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5565<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5566 the function stack to the state it was in when the
5567 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5568 executed. This is useful for implementing language features like scoped
5569 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5570
5571<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5572<p>See the description
5573 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5574
5575</div>
5576
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5577<!-- _______________________________________________________________________ -->
5578<div class="doc_subsubsection">
5579 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5580</div>
5581
5582<div class="doc_text">
5583
5584<h5>Syntax:</h5>
5585<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5586 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]5587</pre>
5588
5589<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5590<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5591 insert a prefetch instruction if supported; otherwise, it is a noop.
5592 Prefetches have no effect on the behavior of the program but can change its
5593 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5594
5595<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5596<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5597 specifier determining if the fetch should be for a read (0) or write (1),
5598 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5599 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5600 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5601
5602<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5603<p>This intrinsic does not modify the behavior of the program. In particular,
5604 prefetches cannot trap and do not produce a value. On targets that support
5605 this intrinsic, the prefetch can provide hints to the processor cache for
5606 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5607
5608</div>
5609
5610<!-- _______________________________________________________________________ -->
5611<div class="doc_subsubsection">
5612 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5613</div>
5614
5615<div class="doc_text">
5616
5617<h5>Syntax:</h5>
5618<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5619 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5620</pre>
5621
5622<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5623<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5624 Counter (PC) in a region of code to simulators and other tools. The method
5625 is target specific, but it is expected that the marker will use exported
5626 symbols to transmit the PC of the marker. The marker makes no guarantees
5627 that it will remain with any specific instruction after optimizations. It is
5628 possible that the presence of a marker will inhibit optimizations. The
5629 intended use is to be inserted after optimizations to allow correlations of
5630 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5631
5632<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5633<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5634
5635<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5636<p>This intrinsic does not modify the behavior of the program. Backends that do
5637 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5638
5639</div>
5640
5641<!-- _______________________________________________________________________ -->
5642<div class="doc_subsubsection">
5643 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5644</div>
5645
5646<div class="doc_text">
5647
5648<h5>Syntax:</h5>
5649<pre>
5650 declare i64 @llvm.readcyclecounter( )
5651</pre>
5652
5653<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5654<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5655 counter register (or similar low latency, high accuracy clocks) on those
5656 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5657 should map to RPCC. As the backing counters overflow quickly (on the order
5658 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5659
5660<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5661<p>When directly supported, reading the cycle counter should not modify any
5662 memory. Implementations are allowed to either return a application specific
5663 value or a system wide value. On backends without support, this is lowered
5664 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5665
5666</div>
5667
5668<!-- ======================================================================= -->
5669<div class="doc_subsection">
5670 <a name="int_libc">Standard C Library Intrinsics</a>
5671</div>
5672
5673<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5674
5675<p>LLVM provides intrinsics for a few important standard C library functions.
5676 These intrinsics allow source-language front-ends to pass information about
5677 the alignment of the pointer arguments to the code generator, providing
5678 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5679
5680</div>
5681
5682<!-- _______________________________________________________________________ -->
5683<div class="doc_subsubsection">
5684 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5685</div>
5686
5687<div class="doc_text">
5688
5689<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5690<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5691 integer bit width. Not all targets support all bit widths however.</p>
5692
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5693<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5694 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5695 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5696 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5697 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5698 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5699 i32 &lt;len&gt;, i32 &lt;align&gt;)
5700 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5701 i64 &lt;len&gt;, i32 &lt;align&gt;)
5702</pre>
5703
5704<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5705<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5706 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5707
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5708<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5709 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5710
5711<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5712<p>The first argument is a pointer to the destination, the second is a pointer
5713 to the source. The third argument is an integer argument specifying the
5714 number of bytes to copy, and the fourth argument is the alignment of the
5715 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5716
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5717<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5718 then the caller guarantees that both the source and destination pointers are
5719 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5720
5721<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5722<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5723 source location to the destination location, which are not allowed to
5724 overlap. It copies "len" bytes of memory over. If the argument is known to
5725 be aligned to some boundary, this can be specified as the fourth argument,
5726 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5727
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5728</div>
5729
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5730<!-- _______________________________________________________________________ -->
5731<div class="doc_subsubsection">
5732 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5733</div>
5734
5735<div class="doc_text">
5736
5737<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5738<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]5739 width. Not all targets support all bit widths however.</p>
5740
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5741<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5742 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5743 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5744 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5745 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5746 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5747 i32 &lt;len&gt;, i32 &lt;align&gt;)
5748 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5749 i64 &lt;len&gt;, i32 &lt;align&gt;)
5750</pre>
5751
5752<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5753<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5754 source location to the destination location. It is similar to the
5755 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5756 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5757
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5758<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5759 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5760
5761<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5762<p>The first argument is a pointer to the destination, the second is a pointer
5763 to the source. The third argument is an integer argument specifying the
5764 number of bytes to copy, and the fourth argument is the alignment of the
5765 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5766
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5767<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5768 then the caller guarantees that the source and destination pointers are
5769 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5770
5771<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5772<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5773 source location to the destination location, which may overlap. It copies
5774 "len" bytes of memory over. If the argument is known to be aligned to some
5775 boundary, this can be specified as the fourth argument, otherwise it should
5776 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5777
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5778</div>
5779
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5780<!-- _______________________________________________________________________ -->
5781<div class="doc_subsubsection">
5782 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5783</div>
5784
5785<div class="doc_text">
5786
5787<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5788<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]5789 width. Not all targets support all bit widths however.</p>
5790
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5791<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5792 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5793 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5794 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5795 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5796 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5797 i32 &lt;len&gt;, i32 &lt;align&gt;)
5798 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5799 i64 &lt;len&gt;, i32 &lt;align&gt;)
5800</pre>
5801
5802<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5803<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5804 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5805
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5806<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5807 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5808
5809<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5810<p>The first argument is a pointer to the destination to fill, the second is the
5811 byte value to fill it with, the third argument is an integer argument
5812 specifying the number of bytes to fill, and the fourth argument is the known
5813 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5814
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5815<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5816 then the caller guarantees that the destination pointer is aligned to that
5817 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5818
5819<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5820<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5821 at the destination location. If the argument is known to be aligned to some
5822 boundary, this can be specified as the fourth argument, otherwise it should
5823 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5824
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5825</div>
5826
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5827<!-- _______________________________________________________________________ -->
5828<div class="doc_subsubsection">
5829 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5830</div>
5831
5832<div class="doc_text">
5833
5834<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5835<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5836 floating point or vector of floating point type. Not all targets support all
5837 types however.</p>
5838
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5839<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5840 declare float @llvm.sqrt.f32(float %Val)
5841 declare double @llvm.sqrt.f64(double %Val)
5842 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5843 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5844 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5845</pre>
5846
5847<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5848<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5849 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5850 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5851 behavior for negative numbers other than -0.0 (which allows for better
5852 optimization, because there is no need to worry about errno being
5853 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]5854
5855<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5856<p>The argument and return value are floating point numbers of the same
5857 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5858
5859<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5860<p>This function returns the sqrt of the specified operand if it is a
5861 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5862
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5863</div>
5864
5865<!-- _______________________________________________________________________ -->
5866<div class="doc_subsubsection">
5867 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5868</div>
5869
5870<div class="doc_text">
5871
5872<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5873<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5874 floating point or vector of floating point type. Not all targets support all
5875 types however.</p>
5876
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5877<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5878 declare float @llvm.powi.f32(float %Val, i32 %power)
5879 declare double @llvm.powi.f64(double %Val, i32 %power)
5880 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5881 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5882 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5883</pre>
5884
5885<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5886<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5887 specified (positive or negative) power. The order of evaluation of
5888 multiplications is not defined. When a vector of floating point type is
5889 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5890
5891<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5892<p>The second argument is an integer power, and the first is a value to raise to
5893 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5894
5895<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5896<p>This function returns the first value raised to the second power with an
5897 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5898
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5899</div>
5900
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5901<!-- _______________________________________________________________________ -->
5902<div class="doc_subsubsection">
5903 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5904</div>
5905
5906<div class="doc_text">
5907
5908<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5909<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5910 floating point or vector of floating point type. Not all targets support all
5911 types however.</p>
5912
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5913<pre>
5914 declare float @llvm.sin.f32(float %Val)
5915 declare double @llvm.sin.f64(double %Val)
5916 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5917 declare fp128 @llvm.sin.f128(fp128 %Val)
5918 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5919</pre>
5920
5921<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5922<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5923
5924<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5925<p>The argument and return value are floating point numbers of the same
5926 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5927
5928<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5929<p>This function returns the sine of the specified operand, returning the same
5930 values as the libm <tt>sin</tt> functions would, and handles error conditions
5931 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5932
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5933</div>
5934
5935<!-- _______________________________________________________________________ -->
5936<div class="doc_subsubsection">
5937 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5938</div>
5939
5940<div class="doc_text">
5941
5942<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5943<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5944 floating point or vector of floating point type. Not all targets support all
5945 types however.</p>
5946
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5947<pre>
5948 declare float @llvm.cos.f32(float %Val)
5949 declare double @llvm.cos.f64(double %Val)
5950 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5951 declare fp128 @llvm.cos.f128(fp128 %Val)
5952 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5953</pre>
5954
5955<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5956<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</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 argument and return value are floating point numbers of the same
5960 type.</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 cosine of the specified operand, returning the same
5964 values as the libm <tt>cos</tt> functions would, and handles error conditions
5965 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
5969<!-- _______________________________________________________________________ -->
5970<div class="doc_subsubsection">
5971 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5972</div>
5973
5974<div class="doc_text">
5975
5976<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5977<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5978 floating point or vector of floating point type. Not all targets support all
5979 types however.</p>
5980
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5981<pre>
5982 declare float @llvm.pow.f32(float %Val, float %Power)
5983 declare double @llvm.pow.f64(double %Val, double %Power)
5984 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5985 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5986 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5987</pre>
5988
5989<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5990<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5991 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5992
5993<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5994<p>The second argument is a floating point power, and the first is a value to
5995 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5996
5997<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5998<p>This function returns the first value raised to the second power, returning
5999 the same values as the libm <tt>pow</tt> functions would, and handles error
6000 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6001
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6002</div>
6003
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6004<!-- ======================================================================= -->
6005<div class="doc_subsection">
6006 <a name="int_manip">Bit Manipulation Intrinsics</a>
6007</div>
6008
6009<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6010
6011<p>LLVM provides intrinsics for a few important bit manipulation operations.
6012 These allow efficient code generation for some algorithms.</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_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
6019</div>
6020
6021<div class="doc_text">
6022
6023<h5>Syntax:</h5>
6024<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6025 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6026
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6027<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6028 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6029 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6030 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6031</pre>
6032
6033<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6034<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6035 values with an even number of bytes (positive multiple of 16 bits). These
6036 are useful for performing operations on data that is not in the target's
6037 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6038
6039<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6040<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6041 and low byte of the input i16 swapped. Similarly,
6042 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6043 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6044 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6045 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6046 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6047 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6048
6049</div>
6050
6051<!-- _______________________________________________________________________ -->
6052<div class="doc_subsubsection">
6053 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6054</div>
6055
6056<div class="doc_text">
6057
6058<h5>Syntax:</h5>
6059<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]6060 width. Not all targets support all bit widths however.</p>
6061
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6062<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6063 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6064 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6065 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6066 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6067 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6068</pre>
6069
6070<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6071<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6072 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6073
6074<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6075<p>The only argument is the value to be counted. The argument may be of any
6076 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6077
6078<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6079<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]6080
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6081</div>
6082
6083<!-- _______________________________________________________________________ -->
6084<div class="doc_subsubsection">
6085 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6086</div>
6087
6088<div class="doc_text">
6089
6090<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6091<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6092 integer bit width. Not all targets support all bit widths however.</p>
6093
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6094<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6095 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6096 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6097 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6098 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6099 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6100</pre>
6101
6102<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6103<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6104 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6105
6106<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6107<p>The only argument is the value to be counted. The argument may be of any
6108 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6109
6110<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6111<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6112 zeros in a variable. If the src == 0 then the result is the size in bits of
6113 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6114
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6115</div>
6116
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6117<!-- _______________________________________________________________________ -->
6118<div class="doc_subsubsection">
6119 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6120</div>
6121
6122<div class="doc_text">
6123
6124<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6125<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6126 integer bit width. Not all targets support all bit widths however.</p>
6127
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6128<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6129 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6130 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6131 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6132 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6133 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6134</pre>
6135
6136<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6137<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6138 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6139
6140<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6141<p>The only argument is the value to be counted. The argument may be of any
6142 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6143
6144<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6145<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6146 zeros in a variable. If the src == 0 then the result is the size in bits of
6147 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6148
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6149</div>
6150
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6151<!-- ======================================================================= -->
6152<div class="doc_subsection">
6153 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6154</div>
6155
6156<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6157
6158<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6159
6160</div>
6161
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6162<!-- _______________________________________________________________________ -->
6163<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6164 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6165</div>
6166
6167<div class="doc_text">
6168
6169<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6170<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]6171 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6172
6173<pre>
6174 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6175 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6176 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6177</pre>
6178
6179<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6180<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6181 a signed addition of the two arguments, and indicate whether an overflow
6182 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6183
6184<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6185<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]6186 be of integer types of any bit width, but they must have the same bit
6187 width. The second element of the result structure must be of
6188 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6189 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6190
6191<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6192<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6193 a signed addition of the two variables. They return a structure &mdash; the
6194 first element of which is the signed summation, and the second element of
6195 which is a bit specifying if the signed summation resulted in an
6196 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6197
6198<h5>Examples:</h5>
6199<pre>
6200 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6201 %sum = extractvalue {i32, i1} %res, 0
6202 %obit = extractvalue {i32, i1} %res, 1
6203 br i1 %obit, label %overflow, label %normal
6204</pre>
6205
6206</div>
6207
6208<!-- _______________________________________________________________________ -->
6209<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6210 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6211</div>
6212
6213<div class="doc_text">
6214
6215<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6216<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]6217 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6218
6219<pre>
6220 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6221 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6222 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6223</pre>
6224
6225<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6226<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6227 an unsigned addition of the two arguments, and indicate whether a carry
6228 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6229
6230<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6231<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]6232 be of integer types of any bit width, but they must have the same bit
6233 width. The second element of the result structure must be of
6234 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6235 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6236
6237<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6238<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6239 an unsigned addition of the two arguments. They return a structure &mdash;
6240 the first element of which is the sum, and the second element of which is a
6241 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6242
6243<h5>Examples:</h5>
6244<pre>
6245 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6246 %sum = extractvalue {i32, i1} %res, 0
6247 %obit = extractvalue {i32, i1} %res, 1
6248 br i1 %obit, label %carry, label %normal
6249</pre>
6250
6251</div>
6252
6253<!-- _______________________________________________________________________ -->
6254<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6255 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6256</div>
6257
6258<div class="doc_text">
6259
6260<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6261<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]6262 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6263
6264<pre>
6265 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6266 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6267 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6268</pre>
6269
6270<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6271<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6272 a signed subtraction of the two arguments, and indicate whether an overflow
6273 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6274
6275<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6276<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]6277 be of integer types of any bit width, but they must have the same bit
6278 width. The second element of the result structure must be of
6279 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6280 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6281
6282<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6283<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6284 a signed subtraction of the two arguments. They return a structure &mdash;
6285 the first element of which is the subtraction, and the second element of
6286 which is a bit specifying if the signed subtraction resulted in an
6287 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6288
6289<h5>Examples:</h5>
6290<pre>
6291 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6292 %sum = extractvalue {i32, i1} %res, 0
6293 %obit = extractvalue {i32, i1} %res, 1
6294 br i1 %obit, label %overflow, label %normal
6295</pre>
6296
6297</div>
6298
6299<!-- _______________________________________________________________________ -->
6300<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6301 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6302</div>
6303
6304<div class="doc_text">
6305
6306<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6307<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]6308 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6309
6310<pre>
6311 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6312 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6313 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6314</pre>
6315
6316<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6317<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6318 an unsigned subtraction of the two arguments, and indicate whether an
6319 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6320
6321<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6322<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]6323 be of integer types of any bit width, but they must have the same bit
6324 width. The second element of the result structure must be of
6325 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6326 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6327
6328<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6329<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6330 an unsigned subtraction of the two arguments. They return a structure &mdash;
6331 the first element of which is the subtraction, and the second element of
6332 which is a bit specifying if the unsigned subtraction resulted in an
6333 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6334
6335<h5>Examples:</h5>
6336<pre>
6337 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6338 %sum = extractvalue {i32, i1} %res, 0
6339 %obit = extractvalue {i32, i1} %res, 1
6340 br i1 %obit, label %overflow, label %normal
6341</pre>
6342
6343</div>
6344
6345<!-- _______________________________________________________________________ -->
6346<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6347 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6348</div>
6349
6350<div class="doc_text">
6351
6352<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6353<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]6354 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6355
6356<pre>
6357 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6358 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6359 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6360</pre>
6361
6362<h5>Overview:</h5>
6363
6364<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6365 a signed multiplication of the two arguments, and indicate whether an
6366 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6367
6368<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6369<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]6370 be of integer types of any bit width, but they must have the same bit
6371 width. The second element of the result structure must be of
6372 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6373 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6374
6375<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6376<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6377 a signed multiplication of the two arguments. They return a structure &mdash;
6378 the first element of which is the multiplication, and the second element of
6379 which is a bit specifying if the signed multiplication resulted in an
6380 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6381
6382<h5>Examples:</h5>
6383<pre>
6384 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6385 %sum = extractvalue {i32, i1} %res, 0
6386 %obit = extractvalue {i32, i1} %res, 1
6387 br i1 %obit, label %overflow, label %normal
6388</pre>
6389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6390</div>
6391
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6392<!-- _______________________________________________________________________ -->
6393<div class="doc_subsubsection">
6394 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6395</div>
6396
6397<div class="doc_text">
6398
6399<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6400<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]6401 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6402
6403<pre>
6404 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6405 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6406 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6407</pre>
6408
6409<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6410<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6411 a unsigned multiplication of the two arguments, and indicate whether an
6412 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6413
6414<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6415<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]6416 be of integer types of any bit width, but they must have the same bit
6417 width. The second element of the result structure must be of
6418 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6419 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6420
6421<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6422<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6423 an unsigned multiplication of the two arguments. They return a structure
6424 &mdash; the first element of which is the multiplication, and the second
6425 element of which is a bit specifying if the unsigned multiplication resulted
6426 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6427
6428<h5>Examples:</h5>
6429<pre>
6430 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6431 %sum = extractvalue {i32, i1} %res, 0
6432 %obit = extractvalue {i32, i1} %res, 1
6433 br i1 %obit, label %overflow, label %normal
6434</pre>
6435
6436</div>
6437
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6438<!-- ======================================================================= -->
6439<div class="doc_subsection">
6440 <a name="int_debugger">Debugger Intrinsics</a>
6441</div>
6442
6443<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6444
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6445<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6446 prefix), are described in
6447 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6448 Level Debugging</a> document.</p>
6449
6450</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6451
6452<!-- ======================================================================= -->
6453<div class="doc_subsection">
6454 <a name="int_eh">Exception Handling Intrinsics</a>
6455</div>
6456
6457<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6458
6459<p>The LLVM exception handling intrinsics (which all start with
6460 <tt>llvm.eh.</tt> prefix), are described in
6461 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6462 Handling</a> document.</p>
6463
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6464</div>
6465
6466<!-- ======================================================================= -->
6467<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6468 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6469</div>
6470
6471<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6472
6473<p>This intrinsic makes it possible to excise one parameter, marked with
6474 the <tt>nest</tt> attribute, from a function. The result is a callable
6475 function pointer lacking the nest parameter - the caller does not need to
6476 provide a value for it. Instead, the value to use is stored in advance in a
6477 "trampoline", a block of memory usually allocated on the stack, which also
6478 contains code to splice the nest value into the argument list. This is used
6479 to implement the GCC nested function address extension.</p>
6480
6481<p>For example, if the function is
6482 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6483 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6484 follows:</p>
6485
6486<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6487<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6488 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6489 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6490 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6491 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6492</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6493</div>
6494
6495<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6496 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6497
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6498</div>
6499
6500<!-- _______________________________________________________________________ -->
6501<div class="doc_subsubsection">
6502 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6503</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6504
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6505<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6506
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6507<h5>Syntax:</h5>
6508<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6509 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]6510</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6511
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6512<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6513<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6514 function pointer suitable for executing it.</p>
6515
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6516<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6517<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6518 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6519 sufficiently aligned block of memory; this memory is written to by the
6520 intrinsic. Note that the size and the alignment are target-specific - LLVM
6521 currently provides no portable way of determining them, so a front-end that
6522 generates this intrinsic needs to have some target-specific knowledge.
6523 The <tt>func</tt> argument must hold a function bitcast to
6524 an <tt>i8*</tt>.</p>
6525
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6526<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6527<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6528 dependent code, turning it into a function. A pointer to this function is
6529 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6530 function pointer type</a> before being called. The new function's signature
6531 is the same as that of <tt>func</tt> with any arguments marked with
6532 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6533 is allowed, and it must be of pointer type. Calling the new function is
6534 equivalent to calling <tt>func</tt> with the same argument list, but
6535 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6536 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6537 by <tt>tramp</tt> is modified, then the effect of any later call to the
6538 returned function pointer is undefined.</p>
6539
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6540</div>
6541
6542<!-- ======================================================================= -->
6543<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6544 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6545</div>
6546
6547<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6548
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6549<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6550 hardware constructs for atomic operations and memory synchronization. This
6551 provides an interface to the hardware, not an interface to the programmer. It
6552 is aimed at a low enough level to allow any programming models or APIs
6553 (Application Programming Interfaces) which need atomic behaviors to map
6554 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6555 hardware provides a "universal IR" for source languages, it also provides a
6556 starting point for developing a "universal" atomic operation and
6557 synchronization IR.</p>
6558
6559<p>These do <em>not</em> form an API such as high-level threading libraries,
6560 software transaction memory systems, atomic primitives, and intrinsic
6561 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6562 application libraries. The hardware interface provided by LLVM should allow
6563 a clean implementation of all of these APIs and parallel programming models.
6564 No one model or paradigm should be selected above others unless the hardware
6565 itself ubiquitously does so.</p>
6566
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6567</div>
6568
6569<!-- _______________________________________________________________________ -->
6570<div class="doc_subsubsection">
6571 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6572</div>
6573<div class="doc_text">
6574<h5>Syntax:</h5>
6575<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6576 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]6577</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6578
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6579<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6580<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6581 specific pairs of memory access types.</p>
6582
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6583<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6584<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6585 The first four arguments enables a specific barrier as listed below. The
6586 fith argument specifies that the barrier applies to io or device or uncached
6587 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6588
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6589<ul>
6590 <li><tt>ll</tt>: load-load barrier</li>
6591 <li><tt>ls</tt>: load-store barrier</li>
6592 <li><tt>sl</tt>: store-load barrier</li>
6593 <li><tt>ss</tt>: store-store barrier</li>
6594 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6595</ul>
6596
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6597<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6598<p>This intrinsic causes the system to enforce some ordering constraints upon
6599 the loads and stores of the program. This barrier does not
6600 indicate <em>when</em> any events will occur, it only enforces
6601 an <em>order</em> in which they occur. For any of the specified pairs of load
6602 and store operations (f.ex. load-load, or store-load), all of the first
6603 operations preceding the barrier will complete before any of the second
6604 operations succeeding the barrier begin. Specifically the semantics for each
6605 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6606
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6607<ul>
6608 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6609 after the barrier begins.</li>
6610 <li><tt>ls</tt>: All loads before the barrier must complete before any
6611 store after the barrier begins.</li>
6612 <li><tt>ss</tt>: All stores before the barrier must complete before any
6613 store after the barrier begins.</li>
6614 <li><tt>sl</tt>: All stores before the barrier must complete before any
6615 load after the barrier begins.</li>
6616</ul>
6617
6618<p>These semantics are applied with a logical "and" behavior when more than one
6619 is enabled in a single memory barrier intrinsic.</p>
6620
6621<p>Backends may implement stronger barriers than those requested when they do
6622 not support as fine grained a barrier as requested. Some architectures do
6623 not need all types of barriers and on such architectures, these become
6624 noops.</p>
6625
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6626<h5>Example:</h5>
6627<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6628%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6629%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6630 store i32 4, %ptr
6631
6632%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6633 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6634 <i>; guarantee the above finishes</i>
6635 store i32 8, %ptr <i>; before this begins</i>
6636</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6637
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6638</div>
6639
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6640<!-- _______________________________________________________________________ -->
6641<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6642 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6643</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6644
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6645<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6646
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6647<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6648<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6649 any integer bit width and for different address spaces. Not all targets
6650 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6651
6652<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6653 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6654 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6655 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6656 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]6657</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6658
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6659<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6660<p>This loads a value in memory and compares it to a given value. If they are
6661 equal, it stores a new value into the memory.</p>
6662
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6663<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6664<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6665 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6666 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6667 this integer type. While any bit width integer may be used, targets may only
6668 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6669
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6670<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6671<p>This entire intrinsic must be executed atomically. It first loads the value
6672 in memory pointed to by <tt>ptr</tt> and compares it with the
6673 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6674 memory. The loaded value is yielded in all cases. This provides the
6675 equivalent of an atomic compare-and-swap operation within the SSA
6676 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6677
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6678<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6679<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6680%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6681%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6682 store i32 4, %ptr
6683
6684%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6685%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6686 <i>; yields {i32}:result1 = 4</i>
6687%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6688%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6689
6690%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6691%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6692 <i>; yields {i32}:result2 = 8</i>
6693%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6694
6695%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6696</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6697
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6698</div>
6699
6700<!-- _______________________________________________________________________ -->
6701<div class="doc_subsubsection">
6702 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6703</div>
6704<div class="doc_text">
6705<h5>Syntax:</h5>
6706
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6707<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6708 integer bit width. Not all targets support all bit widths however.</p>
6709
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6710<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6711 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6712 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6713 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6714 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]6715</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6716
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6717<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6718<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6719 the value from memory. It then stores the value in <tt>val</tt> in the memory
6720 at <tt>ptr</tt>.</p>
6721
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6722<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6723<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6724 the <tt>val</tt> argument and the result must be integers of the same bit
6725 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6726 integer type. The targets may only lower integer representations they
6727 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6728
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6729<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6730<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6731 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6732 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6733
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6734<h5>Examples:</h5>
6735<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6736%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6737%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6738 store i32 4, %ptr
6739
6740%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6741%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6742 <i>; yields {i32}:result1 = 4</i>
6743%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6744%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6745
6746%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6747%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6748 <i>; yields {i32}:result2 = 8</i>
6749
6750%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6751%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6752</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6753
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6754</div>
6755
6756<!-- _______________________________________________________________________ -->
6757<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6758 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6759
6760</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6761
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6762<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6763
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6764<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6765<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6766 any integer bit width. Not all targets support all bit widths however.</p>
6767
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6768<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6769 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6770 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6771 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6772 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]6773</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6774
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6775<h5>Overview:</h5>
6776<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6777 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6778
6779<h5>Arguments:</h5>
6780<p>The intrinsic takes two arguments, the first a pointer to an integer value
6781 and the second an integer value. The result is also an integer value. These
6782 integer types can have any bit width, but they must all have the same bit
6783 width. The targets may only lower integer representations they support.</p>
6784
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6785<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6786<p>This intrinsic does a series of operations atomically. It first loads the
6787 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6788 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]6789
6790<h5>Examples:</h5>
6791<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6792%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6793%ptr = bitcast i8* %mallocP to i32*
6794 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6795%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6796 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6797%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6798 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6799%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6800 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6801%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6802</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6803
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6804</div>
6805
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6806<!-- _______________________________________________________________________ -->
6807<div class="doc_subsubsection">
6808 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6809
6810</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6811
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6812<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6813
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6814<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6815<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6816 any integer bit width and for different address spaces. Not all targets
6817 support all bit widths however.</p>
6818
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6819<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6820 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6821 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6822 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6823 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]6824</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6825
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6826<h5>Overview:</h5>
6827<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6828 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6829
6830<h5>Arguments:</h5>
6831<p>The intrinsic takes two arguments, the first a pointer to an integer value
6832 and the second an integer value. The result is also an integer value. These
6833 integer types can have any bit width, but they must all have the same bit
6834 width. The targets may only lower integer representations they support.</p>
6835
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6836<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6837<p>This intrinsic does a series of operations atomically. It first loads the
6838 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6839 result to <tt>ptr</tt>. It yields the original value stored
6840 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6841
6842<h5>Examples:</h5>
6843<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6844%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6845%ptr = bitcast i8* %mallocP to i32*
6846 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6847%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6848 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6849%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6850 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6851%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6852 <i>; yields {i32}:result3 = 2</i>
6853%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6854</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6855
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6856</div>
6857
6858<!-- _______________________________________________________________________ -->
6859<div class="doc_subsubsection">
6860 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6861 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6862 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6863 <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]6864</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6865
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6866<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6867
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6868<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6869<p>These are overloaded intrinsics. You can
6870 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6871 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6872 bit width and for different address spaces. Not all targets support all bit
6873 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6874
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6875<pre>
6876 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6877 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6878 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6879 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]6880</pre>
6881
6882<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6883 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6884 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6885 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6886 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]6887</pre>
6888
6889<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6890 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6891 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6892 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6893 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]6894</pre>
6895
6896<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6897 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6898 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6899 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6900 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]6901</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6902
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6903<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6904<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6905 the value stored in memory at <tt>ptr</tt>. It yields the original value
6906 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6907
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6908<h5>Arguments:</h5>
6909<p>These intrinsics take two arguments, the first a pointer to an integer value
6910 and the second an integer value. The result is also an integer value. These
6911 integer types can have any bit width, but they must all have the same bit
6912 width. The targets may only lower integer representations they support.</p>
6913
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6914<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6915<p>These intrinsics does a series of operations atomically. They first load the
6916 value stored at <tt>ptr</tt>. They then do the bitwise
6917 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6918 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6919
6920<h5>Examples:</h5>
6921<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6922%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6923%ptr = bitcast i8* %mallocP to i32*
6924 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6925%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6926 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6927%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6928 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6929%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6930 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6931%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6932 <i>; yields {i32}:result3 = FF</i>
6933%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6934</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6935
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6936</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6937
6938<!-- _______________________________________________________________________ -->
6939<div class="doc_subsubsection">
6940 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6941 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6942 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6943 <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]6944</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6945
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6946<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6947
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6948<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6949<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6950 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6951 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6952 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6953
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6954<pre>
6955 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6956 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6957 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6958 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]6959</pre>
6960
6961<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6962 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6963 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6964 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6965 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]6966</pre>
6967
6968<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6969 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6970 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6971 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6972 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]6973</pre>
6974
6975<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6976 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6977 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6978 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6979 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]6980</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6981
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6982<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6983<p>These intrinsics takes the signed or unsigned minimum or maximum of
6984 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6985 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6986
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6987<h5>Arguments:</h5>
6988<p>These intrinsics take two arguments, the first a pointer to an integer value
6989 and the second an integer value. The result is also an integer value. These
6990 integer types can have any bit width, but they must all have the same bit
6991 width. The targets may only lower integer representations they support.</p>
6992
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6993<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6994<p>These intrinsics does a series of operations atomically. They first load the
6995 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6996 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6997 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6998
6999<h5>Examples:</h5>
7000<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7001%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7002%ptr = bitcast i8* %mallocP to i32*
7003 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7004%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7005 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7006%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7007 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7008%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7009 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7010%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7011 <i>; yields {i32}:result3 = 8</i>
7012%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7013</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7014
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7015</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7016
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7017
7018<!-- ======================================================================= -->
7019<div class="doc_subsection">
7020 <a name="int_memorymarkers">Memory Use Markers</a>
7021</div>
7022
7023<div class="doc_text">
7024
7025<p>This class of intrinsics exists to information about the lifetime of memory
7026 objects and ranges where variables are immutable.</p>
7027
7028</div>
7029
7030<!-- _______________________________________________________________________ -->
7031<div class="doc_subsubsection">
7032 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7033</div>
7034
7035<div class="doc_text">
7036
7037<h5>Syntax:</h5>
7038<pre>
7039 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7040</pre>
7041
7042<h5>Overview:</h5>
7043<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7044 object's lifetime.</p>
7045
7046<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7047<p>The first argument is a constant integer representing the size of the
7048 object, or -1 if it is variable sized. The second argument is a pointer to
7049 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7050
7051<h5>Semantics:</h5>
7052<p>This intrinsic indicates that before this point in the code, the value of the
7053 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
Nick Lewyckyf8a5f302009-10-27 16:56:58 +0000[diff] [blame]7054 never be used and has an undefined value. A load from the pointer that
7055 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7056 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7057
7058</div>
7059
7060<!-- _______________________________________________________________________ -->
7061<div class="doc_subsubsection">
7062 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7063</div>
7064
7065<div class="doc_text">
7066
7067<h5>Syntax:</h5>
7068<pre>
7069 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7070</pre>
7071
7072<h5>Overview:</h5>
7073<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7074 object's lifetime.</p>
7075
7076<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7077<p>The first argument is a constant integer representing the size of the
7078 object, or -1 if it is variable sized. The second argument is a pointer to
7079 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7080
7081<h5>Semantics:</h5>
7082<p>This intrinsic indicates that after this point in the code, the value of the
7083 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7084 never be used and has an undefined value. Any stores into the memory object
7085 following this intrinsic may be removed as dead.
7086
7087</div>
7088
7089<!-- _______________________________________________________________________ -->
7090<div class="doc_subsubsection">
7091 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7092</div>
7093
7094<div class="doc_text">
7095
7096<h5>Syntax:</h5>
7097<pre>
7098 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7099</pre>
7100
7101<h5>Overview:</h5>
7102<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7103 a memory object will not change.</p>
7104
7105<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7106<p>The first argument is a constant integer representing the size of the
7107 object, or -1 if it is variable sized. The second argument is a pointer to
7108 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7109
7110<h5>Semantics:</h5>
7111<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7112 the return value, the referenced memory location is constant and
7113 unchanging.</p>
7114
7115</div>
7116
7117<!-- _______________________________________________________________________ -->
7118<div class="doc_subsubsection">
7119 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7120</div>
7121
7122<div class="doc_text">
7123
7124<h5>Syntax:</h5>
7125<pre>
7126 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7127</pre>
7128
7129<h5>Overview:</h5>
7130<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7131 a memory object are mutable.</p>
7132
7133<h5>Arguments:</h5>
7134<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7135 The second argument is a constant integer representing the size of the
7136 object, or -1 if it is variable sized and the third argument is a pointer
7137 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7138
7139<h5>Semantics:</h5>
7140<p>This intrinsic indicates that the memory is mutable again.</p>
7141
7142</div>
7143
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7144<!-- ======================================================================= -->
7145<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7146 <a name="int_general">General Intrinsics</a>
7147</div>
7148
7149<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7150
7151<p>This class of intrinsics is designed to be generic and has no specific
7152 purpose.</p>
7153
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7154</div>
7155
7156<!-- _______________________________________________________________________ -->
7157<div class="doc_subsubsection">
7158 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7159</div>
7160
7161<div class="doc_text">
7162
7163<h5>Syntax:</h5>
7164<pre>
7165 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7166</pre>
7167
7168<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7169<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7170
7171<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7172<p>The first argument is a pointer to a value, the second is a pointer to a
7173 global string, the third is a pointer to a global string which is the source
7174 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7175
7176<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7177<p>This intrinsic allows annotation of local variables with arbitrary strings.
7178 This can be useful for special purpose optimizations that want to look for
7179 these annotations. These have no other defined use, they are ignored by code
7180 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7181
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7182</div>
7183
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7184<!-- _______________________________________________________________________ -->
7185<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7186 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7187</div>
7188
7189<div class="doc_text">
7190
7191<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7192<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7193 any integer bit width.</p>
7194
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7195<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7196 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7197 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7198 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7199 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7200 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]7201</pre>
7202
7203<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7204<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7205
7206<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7207<p>The first argument is an integer value (result of some expression), the
7208 second is a pointer to a global string, the third is a pointer to a global
7209 string which is the source file name, and the last argument is the line
7210 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7211
7212<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7213<p>This intrinsic allows annotations to be put on arbitrary expressions with
7214 arbitrary strings. This can be useful for special purpose optimizations that
7215 want to look for these annotations. These have no other defined use, they
7216 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7217
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7218</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7219
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7220<!-- _______________________________________________________________________ -->
7221<div class="doc_subsubsection">
7222 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7223</div>
7224
7225<div class="doc_text">
7226
7227<h5>Syntax:</h5>
7228<pre>
7229 declare void @llvm.trap()
7230</pre>
7231
7232<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7233<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7234
7235<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7236<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7237
7238<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7239<p>This intrinsics is lowered to the target dependent trap instruction. If the
7240 target does not have a trap instruction, this intrinsic will be lowered to
7241 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7242
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7243</div>
7244
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7245<!-- _______________________________________________________________________ -->
7246<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7247 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7248</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7249
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7250<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7251
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7252<h5>Syntax:</h5>
7253<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7254 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7255</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7256
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7257<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7258<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7259 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7260 ensure that it is placed on the stack before local variables.</p>
7261
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7262<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7263<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7264 arguments. The first argument is the value loaded from the stack
7265 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7266 that has enough space to hold the value of the guard.</p>
7267
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7268<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7269<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7270 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7271 stack. This is to ensure that if a local variable on the stack is
7272 overwritten, it will destroy the value of the guard. When the function exits,
7273 the guard on the stack is checked against the original guard. If they're
7274 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7275 function.</p>
7276
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7277</div>
7278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7279<!-- *********************************************************************** -->
7280<hr>
7281<address>
7282 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7283 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7284 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7285 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7286
7287 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7288 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7289 Last modified: $Date$
7290</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7291
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7292</body>
7293</html>