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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 8c98a898f4a96088bd6af151e1573ef9cdef0bac / . / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
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>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]46 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]47 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]48 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]49 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]50 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
51 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]52 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]53 </ol>
54 </li>
55 <li><a href="#typesystem">Type System</a>
56 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]57 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]58 <li><a href="#t_primitive">Primitive Types</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]59 <ol>
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]60 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]61 <li><a href="#t_floating">Floating Point Types</a></li>
62 <li><a href="#t_void">Void Type</a></li>
63 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]64 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]65 </ol>
66 </li>
67 <li><a href="#t_derived">Derived Types</a>
68 <ol>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]69 <li><a href="#t_aggregate">Aggregate Types</a>
70 <ol>
71 <li><a href="#t_array">Array Type</a></li>
72 <li><a href="#t_struct">Structure Type</a></li>
73 <li><a href="#t_pstruct">Packed Structure Type</a></li>
74 <li><a href="#t_union">Union Type</a></li>
75 <li><a href="#t_vector">Vector Type</a></li>
76 </ol>
77 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]78 <li><a href="#t_function">Function Type</a></li>
79 <li><a href="#t_pointer">Pointer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]80 <li><a href="#t_opaque">Opaque Type</a></li>
81 </ol>
82 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]83 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]84 </ol>
85 </li>
86 <li><a href="#constants">Constants</a>
87 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]88 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]89 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]90 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
91 <li><a href="#undefvalues">Undefined Values</a></li>
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]92 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#constantexprs">Constant Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]94 </ol>
95 </li>
96 <li><a href="#othervalues">Other Values</a>
97 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]98 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]99 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]100 </ol>
101 </li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]102 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
103 <ol>
104 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]105 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
106 Global Variable</a></li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]107 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
108 Global Variable</a></li>
109 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
110 Global Variable</a></li>
111 </ol>
112 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]113 <li><a href="#instref">Instruction Reference</a>
114 <ol>
115 <li><a href="#terminators">Terminator Instructions</a>
116 <ol>
117 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
118 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
119 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]120 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]121 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
122 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
123 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
124 </ol>
125 </li>
126 <li><a href="#binaryops">Binary Operations</a>
127 <ol>
128 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]129 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]130 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]131 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]132 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]134 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
135 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
136 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
137 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
138 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
139 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
140 </ol>
141 </li>
142 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
143 <ol>
144 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
145 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
146 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
147 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
148 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
149 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
150 </ol>
151 </li>
152 <li><a href="#vectorops">Vector Operations</a>
153 <ol>
154 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
155 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
156 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
157 </ol>
158 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]159 <li><a href="#aggregateops">Aggregate Operations</a>
160 <ol>
161 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
162 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
163 </ol>
164 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]165 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
166 <ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]167 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
168 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
169 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
170 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
171 </ol>
172 </li>
173 <li><a href="#convertops">Conversion Operations</a>
174 <ol>
175 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
176 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
177 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
178 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
179 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
180 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
182 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
183 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
184 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
185 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
186 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
187 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]188 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]189 <li><a href="#otherops">Other Operations</a>
190 <ol>
191 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
192 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
193 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
194 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
195 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
196 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
197 </ol>
198 </li>
199 </ol>
200 </li>
201 <li><a href="#intrinsics">Intrinsic Functions</a>
202 <ol>
203 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
204 <ol>
205 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
206 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
207 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
208 </ol>
209 </li>
210 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
211 <ol>
212 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
213 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
214 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
215 </ol>
216 </li>
217 <li><a href="#int_codegen">Code Generator Intrinsics</a>
218 <ol>
219 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
220 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
221 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
222 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
223 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
224 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
225 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
226 </ol>
227 </li>
228 <li><a href="#int_libc">Standard C Library Intrinsics</a>
229 <ol>
230 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
231 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
232 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
233 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]235 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]238 </ol>
239 </li>
240 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
241 <ol>
242 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
243 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
244 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
245 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]246 </ol>
247 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]248 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
249 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]250 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
251 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
252 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
253 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
254 <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]255 <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]256 </ol>
257 </li>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame^]258 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
259 <ol>
260 <li><a href="#int_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
261 <li><a href="#int_from_fp16">'<tt>llvm.conver.from.fp16</tt>' Intrinsic</a></li>
262 </ol>
263 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]264 <li><a href="#int_debugger">Debugger intrinsics</a></li>
265 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]266 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]267 <ol>
268 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]269 </ol>
270 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]271 <li><a href="#int_atomics">Atomic intrinsics</a>
272 <ol>
273 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
274 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
275 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
276 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
277 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
278 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
279 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
280 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
281 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
282 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
283 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
284 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
285 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
286 </ol>
287 </li>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]288 <li><a href="#int_memorymarkers">Memory Use Markers</a>
289 <ol>
290 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
291 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
292 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
293 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
294 </ol>
295 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]296 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]297 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]298 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]299 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]300 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]301 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]302 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.trap</tt>' Intrinsic</a></li>
304 <li><a href="#int_stackprotector">
305 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]306 <li><a href="#int_objectsize">
307 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]308 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]309 </li>
310 </ol>
311 </li>
312</ol>
313
314<div class="doc_author">
315 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
316 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
317</div>
318
319<!-- *********************************************************************** -->
320<div class="doc_section"> <a name="abstract">Abstract </a></div>
321<!-- *********************************************************************** -->
322
323<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]324
325<p>This document is a reference manual for the LLVM assembly language. LLVM is
326 a Static Single Assignment (SSA) based representation that provides type
327 safety, low-level operations, flexibility, and the capability of representing
328 'all' high-level languages cleanly. It is the common code representation
329 used throughout all phases of the LLVM compilation strategy.</p>
330
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]331</div>
332
333<!-- *********************************************************************** -->
334<div class="doc_section"> <a name="introduction">Introduction</a> </div>
335<!-- *********************************************************************** -->
336
337<div class="doc_text">
338
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]339<p>The LLVM code representation is designed to be used in three different forms:
340 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
341 for fast loading by a Just-In-Time compiler), and as a human readable
342 assembly language representation. This allows LLVM to provide a powerful
343 intermediate representation for efficient compiler transformations and
344 analysis, while providing a natural means to debug and visualize the
345 transformations. The three different forms of LLVM are all equivalent. This
346 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]347
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]348<p>The LLVM representation aims to be light-weight and low-level while being
349 expressive, typed, and extensible at the same time. It aims to be a
350 "universal IR" of sorts, by being at a low enough level that high-level ideas
351 may be cleanly mapped to it (similar to how microprocessors are "universal
352 IR's", allowing many source languages to be mapped to them). By providing
353 type information, LLVM can be used as the target of optimizations: for
354 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]355 variable is never accessed outside of the current function, allowing it to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]356 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]357
358</div>
359
360<!-- _______________________________________________________________________ -->
361<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
362
363<div class="doc_text">
364
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]365<p>It is important to note that this document describes 'well formed' LLVM
366 assembly language. There is a difference between what the parser accepts and
367 what is considered 'well formed'. For example, the following instruction is
368 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]369
370<div class="doc_code">
371<pre>
372%x = <a href="#i_add">add</a> i32 1, %x
373</pre>
374</div>
375
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]376<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
377 LLVM infrastructure provides a verification pass that may be used to verify
378 that an LLVM module is well formed. This pass is automatically run by the
379 parser after parsing input assembly and by the optimizer before it outputs
380 bitcode. The violations pointed out by the verifier pass indicate bugs in
381 transformation passes or input to the parser.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]382
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]383</div>
384
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]385<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]386
387<!-- *********************************************************************** -->
388<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
389<!-- *********************************************************************** -->
390
391<div class="doc_text">
392
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]393<p>LLVM identifiers come in two basic types: global and local. Global
394 identifiers (functions, global variables) begin with the <tt>'@'</tt>
395 character. Local identifiers (register names, types) begin with
396 the <tt>'%'</tt> character. Additionally, there are three different formats
397 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]398
399<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]400 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]401 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
402 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
403 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
404 other characters in their names can be surrounded with quotes. Special
405 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
406 ASCII code for the character in hexadecimal. In this way, any character
407 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]408
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]409 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]410 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]411
412 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]413 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]414</ol>
415
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]416<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]417 don't need to worry about name clashes with reserved words, and the set of
418 reserved words may be expanded in the future without penalty. Additionally,
419 unnamed identifiers allow a compiler to quickly come up with a temporary
420 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]421
422<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]423 languages. There are keywords for different opcodes
424 ('<tt><a href="#i_add">add</a></tt>',
425 '<tt><a href="#i_bitcast">bitcast</a></tt>',
426 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
427 ('<tt><a href="#t_void">void</a></tt>',
428 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
429 reserved words cannot conflict with variable names, because none of them
430 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]431
432<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]433 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]434
435<p>The easy way:</p>
436
437<div class="doc_code">
438<pre>
439%result = <a href="#i_mul">mul</a> i32 %X, 8
440</pre>
441</div>
442
443<p>After strength reduction:</p>
444
445<div class="doc_code">
446<pre>
447%result = <a href="#i_shl">shl</a> i32 %X, i8 3
448</pre>
449</div>
450
451<p>And the hard way:</p>
452
453<div class="doc_code">
454<pre>
Gabor Greifc0ea7672009-10-28 13:05:07 +0000[diff] [blame]455%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
456%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]457%result = <a href="#i_add">add</a> i32 %1, %1
458</pre>
459</div>
460
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]461<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
462 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]463
464<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]465 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]466 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]467
468 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]469 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]470
471 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]472</ol>
473
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]474<p>It also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]475 demonstrating instructions, we will follow an instruction with a comment that
476 defines the type and name of value produced. Comments are shown in italic
477 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]478
479</div>
480
481<!-- *********************************************************************** -->
482<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
483<!-- *********************************************************************** -->
484
485<!-- ======================================================================= -->
486<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
487</div>
488
489<div class="doc_text">
490
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]491<p>LLVM programs are composed of "Module"s, each of which is a translation unit
492 of the input programs. Each module consists of functions, global variables,
493 and symbol table entries. Modules may be combined together with the LLVM
494 linker, which merges function (and global variable) definitions, resolves
495 forward declarations, and merges symbol table entries. Here is an example of
496 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]497
498<div class="doc_code">
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]499<pre>
500<i>; Declare the string constant as a global constant.</i>
501<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]502
503<i>; External declaration of the puts function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]504<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]505
506<i>; Definition of main function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]507define i32 @main() { <i>; i32()* </i>
508 <i>; Convert [13 x i8]* to i8 *...</i>
509 %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]510
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]511 <i>; Call puts function to write out the string to stdout.</i>
512 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]513 <a href="#i_ret">ret</a> i32 0<br>}
514
515<i>; Named metadata</i>
516!1 = metadata !{i32 41}
517!foo = !{!1, null}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]518</pre>
519</div>
520
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]521<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]522 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]523 a <a href="#functionstructure">function definition</a> for
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]524 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
525 "<tt>foo"</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]526
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]527<p>In general, a module is made up of a list of global values, where both
528 functions and global variables are global values. Global values are
529 represented by a pointer to a memory location (in this case, a pointer to an
530 array of char, and a pointer to a function), and have one of the
531 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]532
533</div>
534
535<!-- ======================================================================= -->
536<div class="doc_subsection">
537 <a name="linkage">Linkage Types</a>
538</div>
539
540<div class="doc_text">
541
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]542<p>All Global Variables and Functions have one of the following types of
543 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]544
545<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]546 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]547 <dd>Global values with private linkage are only directly accessible by objects
548 in the current module. In particular, linking code into a module with an
549 private global value may cause the private to be renamed as necessary to
550 avoid collisions. Because the symbol is private to the module, all
551 references can be updated. This doesn't show up in any symbol table in the
552 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]553
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]554 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]555 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattner06c1ecc2009-08-24 04:32:16 +0000[diff] [blame]556 removed by the linker after evaluation. Note that (unlike private
557 symbols) linker_private symbols are subject to coalescing by the linker:
558 weak symbols get merged and redefinitions are rejected. However, unlike
559 normal strong symbols, they are removed by the linker from the final
560 linked image (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]561
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]562 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]563 <dd>Similar to private, but the value shows as a local symbol
564 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
565 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]566
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]567 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]568 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]569 into the object file corresponding to the LLVM module. They exist to
570 allow inlining and other optimizations to take place given knowledge of
571 the definition of the global, which is known to be somewhere outside the
572 module. Globals with <tt>available_externally</tt> linkage are allowed to
573 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
574 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]575
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]576 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]577 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattnerd16c5512010-01-09 19:15:14 +0000[diff] [blame]578 the same name when linkage occurs. This can be used to implement
579 some forms of inline functions, templates, or other code which must be
580 generated in each translation unit that uses it, but where the body may
581 be overridden with a more definitive definition later. Unreferenced
582 <tt>linkonce</tt> globals are allowed to be discarded. Note that
583 <tt>linkonce</tt> linkage does not actually allow the optimizer to
584 inline the body of this function into callers because it doesn't know if
585 this definition of the function is the definitive definition within the
586 program or whether it will be overridden by a stronger definition.
587 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
588 linkage.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]589
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]590 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]591 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
592 <tt>linkonce</tt> linkage, except that unreferenced globals with
593 <tt>weak</tt> linkage may not be discarded. This is used for globals that
594 are declared "weak" in C source code.</dd>
595
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]596 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]597 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
598 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
599 global scope.
600 Symbols with "<tt>common</tt>" linkage are merged in the same way as
601 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]602 <tt>common</tt> symbols may not have an explicit section,
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]603 must have a zero initializer, and may not be marked '<a
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]604 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
605 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]606
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]607
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]608 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]609 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]610 pointer to array type. When two global variables with appending linkage
611 are linked together, the two global arrays are appended together. This is
612 the LLVM, typesafe, equivalent of having the system linker append together
613 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]614
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]615 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]616 <dd>The semantics of this linkage follow the ELF object file model: the symbol
617 is weak until linked, if not linked, the symbol becomes null instead of
618 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]619
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]620 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
621 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]622 <dd>Some languages allow differing globals to be merged, such as two functions
623 with different semantics. Other languages, such as <tt>C++</tt>, ensure
624 that only equivalent globals are ever merged (the "one definition rule" -
625 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
626 and <tt>weak_odr</tt> linkage types to indicate that the global will only
627 be merged with equivalent globals. These linkage types are otherwise the
628 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]629
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]630 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]631 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]632 visible, meaning that it participates in linkage and can be used to
633 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]634</dl>
635
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]636<p>The next two types of linkage are targeted for Microsoft Windows platform
637 only. They are designed to support importing (exporting) symbols from (to)
638 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]639
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]640<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]641 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]642 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]643 or variable via a global pointer to a pointer that is set up by the DLL
644 exporting the symbol. On Microsoft Windows targets, the pointer name is
645 formed by combining <code>__imp_</code> and the function or variable
646 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]647
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]648 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]649 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]650 pointer to a pointer in a DLL, so that it can be referenced with the
651 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
652 name is formed by combining <code>__imp_</code> and the function or
653 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]654</dl>
655
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]656<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
657 another module defined a "<tt>.LC0</tt>" variable and was linked with this
658 one, one of the two would be renamed, preventing a collision. Since
659 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
660 declarations), they are accessible outside of the current module.</p>
661
662<p>It is illegal for a function <i>declaration</i> to have any linkage type
663 other than "externally visible", <tt>dllimport</tt>
664 or <tt>extern_weak</tt>.</p>
665
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]666<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]667 or <tt>weak_odr</tt> linkages.</p>
668
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]669</div>
670
671<!-- ======================================================================= -->
672<div class="doc_subsection">
673 <a name="callingconv">Calling Conventions</a>
674</div>
675
676<div class="doc_text">
677
678<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]679 and <a href="#i_invoke">invokes</a> can all have an optional calling
680 convention specified for the call. The calling convention of any pair of
681 dynamic caller/callee must match, or the behavior of the program is
682 undefined. The following calling conventions are supported by LLVM, and more
683 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]684
685<dl>
686 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]687 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]688 specified) matches the target C calling conventions. This calling
689 convention supports varargs function calls and tolerates some mismatch in
690 the declared prototype and implemented declaration of the function (as
691 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]692
693 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]694 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]695 (e.g. by passing things in registers). This calling convention allows the
696 target to use whatever tricks it wants to produce fast code for the
697 target, without having to conform to an externally specified ABI
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]698 (Application Binary Interface).
699 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnerac9a9392010-03-11 00:22:57 +0000[diff] [blame]700 when this or the GHC convention is used.</a> This calling convention
701 does not support varargs and requires the prototype of all callees to
702 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]703
704 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]705 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]706 as possible under the assumption that the call is not commonly executed.
707 As such, these calls often preserve all registers so that the call does
708 not break any live ranges in the caller side. This calling convention
709 does not support varargs and requires the prototype of all callees to
710 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]711
Chris Lattnerac9a9392010-03-11 00:22:57 +0000[diff] [blame]712 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
713 <dd>This calling convention has been implemented specifically for use by the
714 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
715 It passes everything in registers, going to extremes to achieve this by
716 disabling callee save registers. This calling convention should not be
717 used lightly but only for specific situations such as an alternative to
718 the <em>register pinning</em> performance technique often used when
719 implementing functional programming languages.At the moment only X86
720 supports this convention and it has the following limitations:
721 <ul>
722 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
723 floating point types are supported.</li>
724 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
725 6 floating point parameters.</li>
726 </ul>
727 This calling convention supports
728 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
729 requires both the caller and callee are using it.
730 </dd>
731
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]732 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]733 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]734 target-specific calling conventions to be used. Target specific calling
735 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]736</dl>
737
738<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]739 support Pascal conventions or any other well-known target-independent
740 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]741
742</div>
743
744<!-- ======================================================================= -->
745<div class="doc_subsection">
746 <a name="visibility">Visibility Styles</a>
747</div>
748
749<div class="doc_text">
750
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]751<p>All Global Variables and Functions have one of the following visibility
752 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]753
754<dl>
755 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]756 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]757 that the declaration is visible to other modules and, in shared libraries,
758 means that the declared entity may be overridden. On Darwin, default
759 visibility means that the declaration is visible to other modules. Default
760 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]761
762 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]763 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]764 object if they are in the same shared object. Usually, hidden visibility
765 indicates that the symbol will not be placed into the dynamic symbol
766 table, so no other module (executable or shared library) can reference it
767 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]768
769 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]770 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]771 the dynamic symbol table, but that references within the defining module
772 will bind to the local symbol. That is, the symbol cannot be overridden by
773 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]774</dl>
775
776</div>
777
778<!-- ======================================================================= -->
779<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]780 <a name="namedtypes">Named Types</a>
781</div>
782
783<div class="doc_text">
784
785<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]786 it easier to read the IR and make the IR more condensed (particularly when
787 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]788
789<div class="doc_code">
790<pre>
791%mytype = type { %mytype*, i32 }
792</pre>
793</div>
794
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]795<p>You may give a name to any <a href="#typesystem">type</a> except
796 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
797 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]798
799<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]800 and that you can therefore specify multiple names for the same type. This
801 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
802 uses structural typing, the name is not part of the type. When printing out
803 LLVM IR, the printer will pick <em>one name</em> to render all types of a
804 particular shape. This means that if you have code where two different
805 source types end up having the same LLVM type, that the dumper will sometimes
806 print the "wrong" or unexpected type. This is an important design point and
807 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]808
809</div>
810
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]811<!-- ======================================================================= -->
812<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]813 <a name="globalvars">Global Variables</a>
814</div>
815
816<div class="doc_text">
817
818<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]819 instead of run-time. Global variables may optionally be initialized, may
820 have an explicit section to be placed in, and may have an optional explicit
821 alignment specified. A variable may be defined as "thread_local", which
822 means that it will not be shared by threads (each thread will have a
823 separated copy of the variable). A variable may be defined as a global
824 "constant," which indicates that the contents of the variable
825 will <b>never</b> be modified (enabling better optimization, allowing the
826 global data to be placed in the read-only section of an executable, etc).
827 Note that variables that need runtime initialization cannot be marked
828 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]829
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]830<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
831 constant, even if the final definition of the global is not. This capability
832 can be used to enable slightly better optimization of the program, but
833 requires the language definition to guarantee that optimizations based on the
834 'constantness' are valid for the translation units that do not include the
835 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]836
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]837<p>As SSA values, global variables define pointer values that are in scope
838 (i.e. they dominate) all basic blocks in the program. Global variables
839 always define a pointer to their "content" type because they describe a
840 region of memory, and all memory objects in LLVM are accessed through
841 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]842
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]843<p>A global variable may be declared to reside in a target-specific numbered
844 address space. For targets that support them, address spaces may affect how
845 optimizations are performed and/or what target instructions are used to
846 access the variable. The default address space is zero. The address space
847 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]848
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]849<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]850 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]851
852<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]853 the alignment is set to zero, the alignment of the global is set by the
854 target to whatever it feels convenient. If an explicit alignment is
855 specified, the global is forced to have at least that much alignment. All
856 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]857
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]858<p>For example, the following defines a global in a numbered address space with
859 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]860
861<div class="doc_code">
862<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]863@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]864</pre>
865</div>
866
867</div>
868
869
870<!-- ======================================================================= -->
871<div class="doc_subsection">
872 <a name="functionstructure">Functions</a>
873</div>
874
875<div class="doc_text">
876
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]877<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]878 optional <a href="#linkage">linkage type</a>, an optional
879 <a href="#visibility">visibility style</a>, an optional
880 <a href="#callingconv">calling convention</a>, a return type, an optional
881 <a href="#paramattrs">parameter attribute</a> for the return type, a function
882 name, a (possibly empty) argument list (each with optional
883 <a href="#paramattrs">parameter attributes</a>), optional
884 <a href="#fnattrs">function attributes</a>, an optional section, an optional
885 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
886 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]887
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]888<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
889 optional <a href="#linkage">linkage type</a>, an optional
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]890 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]891 <a href="#callingconv">calling convention</a>, a return type, an optional
892 <a href="#paramattrs">parameter attribute</a> for the return type, a function
893 name, a possibly empty list of arguments, an optional alignment, and an
894 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]895
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]896<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]897 (Control Flow Graph) for the function. Each basic block may optionally start
898 with a label (giving the basic block a symbol table entry), contains a list
899 of instructions, and ends with a <a href="#terminators">terminator</a>
900 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]901
902<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]903 executed on entrance to the function, and it is not allowed to have
904 predecessor basic blocks (i.e. there can not be any branches to the entry
905 block of a function). Because the block can have no predecessors, it also
906 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]907
908<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]909 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]910
911<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]912 the alignment is set to zero, the alignment of the function is set by the
913 target to whatever it feels convenient. If an explicit alignment is
914 specified, the function is forced to have at least that much alignment. All
915 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]916
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]917<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]918<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]919<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]920define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]921 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
922 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
923 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
924 [<a href="#gc">gc</a>] { ... }
925</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]926</div>
927
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]928</div>
929
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]930<!-- ======================================================================= -->
931<div class="doc_subsection">
932 <a name="aliasstructure">Aliases</a>
933</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]934
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]935<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]936
937<p>Aliases act as "second name" for the aliasee value (which can be either
938 function, global variable, another alias or bitcast of global value). Aliases
939 may have an optional <a href="#linkage">linkage type</a>, and an
940 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]941
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]942<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]943<div class="doc_code">
944<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]945@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]946</pre>
947</div>
948
949</div>
950
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]951<!-- ======================================================================= -->
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]952<div class="doc_subsection">
953 <a name="namedmetadatastructure">Named Metadata</a>
954</div>
955
956<div class="doc_text">
957
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]958<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
959 nodes</a> (but not metadata strings) and null are the only valid operands for
960 a named metadata.</p>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]961
962<h5>Syntax:</h5>
963<div class="doc_code">
964<pre>
965!1 = metadata !{metadata !"one"}
966!name = !{null, !1}
967</pre>
968</div>
969
970</div>
971
972<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]973<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]974
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]975<div class="doc_text">
976
977<p>The return type and each parameter of a function type may have a set of
978 <i>parameter attributes</i> associated with them. Parameter attributes are
979 used to communicate additional information about the result or parameters of
980 a function. Parameter attributes are considered to be part of the function,
981 not of the function type, so functions with different parameter attributes
982 can have the same function type.</p>
983
984<p>Parameter attributes are simple keywords that follow the type specified. If
985 multiple parameter attributes are needed, they are space separated. For
986 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]987
988<div class="doc_code">
989<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]990declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]991declare i32 @atoi(i8 zeroext)
992declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]993</pre>
994</div>
995
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]996<p>Note that any attributes for the function result (<tt>nounwind</tt>,
997 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]998
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]999<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1000
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1001<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1002 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1003 <dd>This indicates to the code generator that the parameter or return value
1004 should be zero-extended to a 32-bit value by the caller (for a parameter)
1005 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1006
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1007 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1008 <dd>This indicates to the code generator that the parameter or return value
1009 should be sign-extended to a 32-bit value by the caller (for a parameter)
1010 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1011
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1012 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1013 <dd>This indicates that this parameter or return value should be treated in a
1014 special target-dependent fashion during while emitting code for a function
1015 call or return (usually, by putting it in a register as opposed to memory,
1016 though some targets use it to distinguish between two different kinds of
1017 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1018
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1019 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1020 <dd>This indicates that the pointer parameter should really be passed by value
1021 to the function. The attribute implies that a hidden copy of the pointee
1022 is made between the caller and the callee, so the callee is unable to
1023 modify the value in the callee. This attribute is only valid on LLVM
1024 pointer arguments. It is generally used to pass structs and arrays by
1025 value, but is also valid on pointers to scalars. The copy is considered
1026 to belong to the caller not the callee (for example,
1027 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1028 <tt>byval</tt> parameters). This is not a valid attribute for return
1029 values. The byval attribute also supports specifying an alignment with
1030 the align attribute. This has a target-specific effect on the code
1031 generator that usually indicates a desired alignment for the synthesized
1032 stack slot.</dd>
1033
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1034 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1035 <dd>This indicates that the pointer parameter specifies the address of a
1036 structure that is the return value of the function in the source program.
1037 This pointer must be guaranteed by the caller to be valid: loads and
1038 stores to the structure may be assumed by the callee to not to trap. This
1039 may only be applied to the first parameter. This is not a valid attribute
1040 for return values. </dd>
1041
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1042 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1043 <dd>This indicates that the pointer does not alias any global or any other
1044 parameter. The caller is responsible for ensuring that this is the
1045 case. On a function return value, <tt>noalias</tt> additionally indicates
1046 that the pointer does not alias any other pointers visible to the
1047 caller. For further details, please see the discussion of the NoAlias
1048 response in
1049 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1050 analysis</a>.</dd>
1051
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1052 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1053 <dd>This indicates that the callee does not make any copies of the pointer
1054 that outlive the callee itself. This is not a valid attribute for return
1055 values.</dd>
1056
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1057 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1058 <dd>This indicates that the pointer parameter can be excised using the
1059 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1060 attribute for return values.</dd>
1061</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1062
1063</div>
1064
1065<!-- ======================================================================= -->
1066<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1067 <a name="gc">Garbage Collector Names</a>
1068</div>
1069
1070<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1071
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1072<p>Each function may specify a garbage collector name, which is simply a
1073 string:</p>
1074
1075<div class="doc_code">
1076<pre>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1077define void @f() gc "name" { ... }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1078</pre>
1079</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1080
1081<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1082 collector which will cause the compiler to alter its output in order to
1083 support the named garbage collection algorithm.</p>
1084
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1085</div>
1086
1087<!-- ======================================================================= -->
1088<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1089 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1090</div>
1091
1092<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1093
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1094<p>Function attributes are set to communicate additional information about a
1095 function. Function attributes are considered to be part of the function, not
1096 of the function type, so functions with different parameter attributes can
1097 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1098
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1099<p>Function attributes are simple keywords that follow the type specified. If
1100 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1101
1102<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1103<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1104define void @f() noinline { ... }
1105define void @f() alwaysinline { ... }
1106define void @f() alwaysinline optsize { ... }
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1107define void @f() optsize { ... }
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1108</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1109</div>
1110
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1111<dl>
Charles Davisfaa8f752010-02-12 00:31:15 +0000[diff] [blame]1112 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1113 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1114 the backend should forcibly align the stack pointer. Specify the
1115 desired alignment, which must be a power of two, in parentheses.
1116
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1117 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1118 <dd>This attribute indicates that the inliner should attempt to inline this
1119 function into callers whenever possible, ignoring any active inlining size
1120 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1121
Jakob Stoklund Olesen77180732010-02-06 01:16:28 +0000[diff] [blame]1122 <dt><tt><b>inlinehint</b></tt></dt>
1123 <dd>This attribute indicates that the source code contained a hint that inlining
1124 this function is desirable (such as the "inline" keyword in C/C++). It
1125 is just a hint; it imposes no requirements on the inliner.</dd>
1126
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1127 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1128 <dd>This attribute indicates that the inliner should never inline this
1129 function in any situation. This attribute may not be used together with
1130 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1131
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1132 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1133 <dd>This attribute suggests that optimization passes and code generator passes
1134 make choices that keep the code size of this function low, and otherwise
1135 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1136
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1137 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1138 <dd>This function attribute indicates that the function never returns
1139 normally. This produces undefined behavior at runtime if the function
1140 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1141
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1142 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1143 <dd>This function attribute indicates that the function never returns with an
1144 unwind or exceptional control flow. If the function does unwind, its
1145 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1146
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1147 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1148 <dd>This attribute indicates that the function computes its result (or decides
1149 to unwind an exception) based strictly on its arguments, without
1150 dereferencing any pointer arguments or otherwise accessing any mutable
1151 state (e.g. memory, control registers, etc) visible to caller functions.
1152 It does not write through any pointer arguments
1153 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1154 changes any state visible to callers. This means that it cannot unwind
1155 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1156 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1157
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1158 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1159 <dd>This attribute indicates that the function does not write through any
1160 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1161 arguments) or otherwise modify any state (e.g. memory, control registers,
1162 etc) visible to caller functions. It may dereference pointer arguments
1163 and read state that may be set in the caller. A readonly function always
1164 returns the same value (or unwinds an exception identically) when called
1165 with the same set of arguments and global state. It cannot unwind an
1166 exception by calling the <tt>C++</tt> exception throwing methods, but may
1167 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1168
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1169 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1170 <dd>This attribute indicates that the function should emit a stack smashing
1171 protector. It is in the form of a "canary"&mdash;a random value placed on
1172 the stack before the local variables that's checked upon return from the
1173 function to see if it has been overwritten. A heuristic is used to
1174 determine if a function needs stack protectors or not.<br>
1175<br>
1176 If a function that has an <tt>ssp</tt> attribute is inlined into a
1177 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1178 function will have an <tt>ssp</tt> attribute.</dd>
1179
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1180 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1181 <dd>This attribute indicates that the function should <em>always</em> emit a
1182 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1183 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1184<br>
1185 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1186 function that doesn't have an <tt>sspreq</tt> attribute or which has
1187 an <tt>ssp</tt> attribute, then the resulting function will have
1188 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1189
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1190 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1191 <dd>This attribute indicates that the code generator should not use a red
1192 zone, even if the target-specific ABI normally permits it.</dd>
1193
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1194 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1195 <dd>This attributes disables implicit floating point instructions.</dd>
1196
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1197 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1198 <dd>This attribute disables prologue / epilogue emission for the function.
1199 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1200</dl>
1201
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1202</div>
1203
1204<!-- ======================================================================= -->
1205<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1206 <a name="moduleasm">Module-Level Inline Assembly</a>
1207</div>
1208
1209<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1210
1211<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1212 the GCC "file scope inline asm" blocks. These blocks are internally
1213 concatenated by LLVM and treated as a single unit, but may be separated in
1214 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1215
1216<div class="doc_code">
1217<pre>
1218module asm "inline asm code goes here"
1219module asm "more can go here"
1220</pre>
1221</div>
1222
1223<p>The strings can contain any character by escaping non-printable characters.
1224 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]1225 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1226
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1227<p>The inline asm code is simply printed to the machine code .s file when
1228 assembly code is generated.</p>
1229
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1230</div>
1231
1232<!-- ======================================================================= -->
1233<div class="doc_subsection">
1234 <a name="datalayout">Data Layout</a>
1235</div>
1236
1237<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1238
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1239<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1240 data is to be laid out in memory. The syntax for the data layout is
1241 simply:</p>
1242
1243<div class="doc_code">
1244<pre>
1245target datalayout = "<i>layout specification</i>"
1246</pre>
1247</div>
1248
1249<p>The <i>layout specification</i> consists of a list of specifications
1250 separated by the minus sign character ('-'). Each specification starts with
1251 a letter and may include other information after the letter to define some
1252 aspect of the data layout. The specifications accepted are as follows:</p>
1253
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1254<dl>
1255 <dt><tt>E</tt></dt>
1256 <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]1257 bits with the most significance have the lowest address location.</dd>
1258
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1259 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1260 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1261 the bits with the least significance have the lowest address
1262 location.</dd>
1263
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1264 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1265 <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]1266 <i>preferred</i> alignments. All sizes are in bits. Specifying
1267 the <i>pref</i> alignment is optional. If omitted, the
1268 preceding <tt>:</tt> should be omitted too.</dd>
1269
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1270 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1271 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1272 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1273
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1274 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1275 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1276 <i>size</i>.</dd>
1277
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1278 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1279 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1280 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1281 (double).</dd>
1282
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1283 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1284 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1285 <i>size</i>.</dd>
1286
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1287 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1288 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1289 <i>size</i>.</dd>
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1290
1291 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1292 <dd>This specifies a set of native integer widths for the target CPU
1293 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1294 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1295 this set are considered to support most general arithmetic
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1296 operations efficiently.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1297</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1298
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1299<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1300 default set of specifications which are then (possibly) overriden by the
1301 specifications in the <tt>datalayout</tt> keyword. The default specifications
1302 are given in this list:</p>
1303
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1304<ul>
1305 <li><tt>E</tt> - big endian</li>
Dan Gohmane78194f2010-02-23 02:44:03 +0000[diff] [blame]1306 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1307 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1308 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1309 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1310 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1311 <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]1312 alignment of 64-bits</li>
1313 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1314 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1315 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1316 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1317 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1318 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1319</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1320
1321<p>When LLVM is determining the alignment for a given type, it uses the
1322 following rules:</p>
1323
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1324<ol>
1325 <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]1326 specification is used.</li>
1327
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1328 <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]1329 smallest integer type that is larger than the bitwidth of the sought type
1330 is used. If none of the specifications are larger than the bitwidth then
1331 the the largest integer type is used. For example, given the default
1332 specifications above, the i7 type will use the alignment of i8 (next
1333 largest) while both i65 and i256 will use the alignment of i64 (largest
1334 specified).</li>
1335
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1336 <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]1337 largest vector type that is smaller than the sought vector type will be
1338 used as a fall back. This happens because &lt;128 x double&gt; can be
1339 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1340</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1341
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1342</div>
1343
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1344<!-- ======================================================================= -->
1345<div class="doc_subsection">
1346 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1347</div>
1348
1349<div class="doc_text">
1350
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1351<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1352with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1353is undefined. Pointer values are associated with address ranges
1354according to the following rules:</p>
1355
1356<ul>
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1357 <li>A pointer value formed from a
1358 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1359 is associated with the addresses associated with the first operand
1360 of the <tt>getelementptr</tt>.</li>
1361 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1362 range of the variable's storage.</li>
1363 <li>The result value of an allocation instruction is associated with
1364 the address range of the allocated storage.</li>
1365 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1366 no address.</li>
1367 <li>A pointer value formed by an
1368 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1369 address ranges of all pointer values that contribute (directly or
1370 indirectly) to the computation of the pointer's value.</li>
1371 <li>The result value of a
1372 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1373 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1374 <li>An integer constant other than zero or a pointer value returned
1375 from a function not defined within LLVM may be associated with address
1376 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1377 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1378 allocated by mechanisms provided by LLVM.</li>
1379 </ul>
1380
1381<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1382<tt><a href="#i_load">load</a></tt> merely indicates the size and
1383alignment of the memory from which to load, as well as the
1384interpretation of the value. The first operand of a
1385<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1386and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1387
1388<p>Consequently, type-based alias analysis, aka TBAA, aka
1389<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1390LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1391additional information which specialized optimization passes may use
1392to implement type-based alias analysis.</p>
1393
1394</div>
1395
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1396<!-- *********************************************************************** -->
1397<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1398<!-- *********************************************************************** -->
1399
1400<div class="doc_text">
1401
1402<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1403 intermediate representation. Being typed enables a number of optimizations
1404 to be performed on the intermediate representation directly, without having
1405 to do extra analyses on the side before the transformation. A strong type
1406 system makes it easier to read the generated code and enables novel analyses
1407 and transformations that are not feasible to perform on normal three address
1408 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1409
1410</div>
1411
1412<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1413<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1414Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1415
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1416<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1417
1418<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1419
1420<table border="1" cellspacing="0" cellpadding="4">
1421 <tbody>
1422 <tr><th>Classification</th><th>Types</th></tr>
1423 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1424 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1425 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1426 </tr>
1427 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1428 <td><a href="#t_floating">floating point</a></td>
1429 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1430 </tr>
1431 <tr>
1432 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1433 <td><a href="#t_integer">integer</a>,
1434 <a href="#t_floating">floating point</a>,
1435 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1436 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1437 <a href="#t_struct">structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1438 <a href="#t_union">union</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1439 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1440 <a href="#t_label">label</a>,
1441 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1442 </td>
1443 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1444 <tr>
1445 <td><a href="#t_primitive">primitive</a></td>
1446 <td><a href="#t_label">label</a>,
1447 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1448 <a href="#t_floating">floating point</a>,
1449 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1450 </tr>
1451 <tr>
1452 <td><a href="#t_derived">derived</a></td>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1453 <td><a href="#t_array">array</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1454 <a href="#t_function">function</a>,
1455 <a href="#t_pointer">pointer</a>,
1456 <a href="#t_struct">structure</a>,
1457 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1458 <a href="#t_union">union</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1459 <a href="#t_vector">vector</a>,
1460 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1461 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1462 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1463 </tbody>
1464</table>
1465
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1466<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1467 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1468 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1469
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1470</div>
1471
1472<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1473<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1474
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1475<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1476
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1477<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1478 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1479
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1480</div>
1481
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1482<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1483<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1484
1485<div class="doc_text">
1486
1487<h5>Overview:</h5>
1488<p>The integer type is a very simple type that simply specifies an arbitrary
1489 bit width for the integer type desired. Any bit width from 1 bit to
1490 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1491
1492<h5>Syntax:</h5>
1493<pre>
1494 iN
1495</pre>
1496
1497<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1498 value.</p>
1499
1500<h5>Examples:</h5>
1501<table class="layout">
1502 <tr class="layout">
1503 <td class="left"><tt>i1</tt></td>
1504 <td class="left">a single-bit integer.</td>
1505 </tr>
1506 <tr class="layout">
1507 <td class="left"><tt>i32</tt></td>
1508 <td class="left">a 32-bit integer.</td>
1509 </tr>
1510 <tr class="layout">
1511 <td class="left"><tt>i1942652</tt></td>
1512 <td class="left">a really big integer of over 1 million bits.</td>
1513 </tr>
1514</table>
1515
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1516</div>
1517
1518<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1519<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1520
1521<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1522
1523<table>
1524 <tbody>
1525 <tr><th>Type</th><th>Description</th></tr>
1526 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1527 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1528 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1529 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1530 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1531 </tbody>
1532</table>
1533
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1534</div>
1535
1536<!-- _______________________________________________________________________ -->
1537<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1538
1539<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1540
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1541<h5>Overview:</h5>
1542<p>The void type does not represent any value and has no size.</p>
1543
1544<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1545<pre>
1546 void
1547</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1548
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1549</div>
1550
1551<!-- _______________________________________________________________________ -->
1552<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1553
1554<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1555
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1556<h5>Overview:</h5>
1557<p>The label type represents code labels.</p>
1558
1559<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1560<pre>
1561 label
1562</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1563
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1564</div>
1565
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1566<!-- _______________________________________________________________________ -->
1567<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1568
1569<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1570
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1571<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1572<p>The metadata type represents embedded metadata. No derived types may be
1573 created from metadata except for <a href="#t_function">function</a>
1574 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1575
1576<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1577<pre>
1578 metadata
1579</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1580
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1581</div>
1582
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1583
1584<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1585<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1586
1587<div class="doc_text">
1588
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1589<p>The real power in LLVM comes from the derived types in the system. This is
1590 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1591 useful types. Each of these types contain one or more element types which
1592 may be a primitive type, or another derived type. For example, it is
1593 possible to have a two dimensional array, using an array as the element type
1594 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1595
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1596
1597</div>
1598
1599<!-- _______________________________________________________________________ -->
1600<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1601
1602<div class="doc_text">
1603
1604<p>Aggregate Types are a subset of derived types that can contain multiple
1605 member types. <a href="#t_array">Arrays</a>,
1606 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1607 <a href="#t_union">unions</a> are aggregate types.</p>
1608
1609</div>
1610
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1611</div>
1612
1613<!-- _______________________________________________________________________ -->
1614<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1615
1616<div class="doc_text">
1617
1618<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1619<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1620 sequentially in memory. The array type requires a size (number of elements)
1621 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1622
1623<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1624<pre>
1625 [&lt;# elements&gt; x &lt;elementtype&gt;]
1626</pre>
1627
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1628<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1629 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1630
1631<h5>Examples:</h5>
1632<table class="layout">
1633 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1634 <td class="left"><tt>[40 x i32]</tt></td>
1635 <td class="left">Array of 40 32-bit integer values.</td>
1636 </tr>
1637 <tr class="layout">
1638 <td class="left"><tt>[41 x i32]</tt></td>
1639 <td class="left">Array of 41 32-bit integer values.</td>
1640 </tr>
1641 <tr class="layout">
1642 <td class="left"><tt>[4 x i8]</tt></td>
1643 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1644 </tr>
1645</table>
1646<p>Here are some examples of multidimensional arrays:</p>
1647<table class="layout">
1648 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1649 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1650 <td class="left">3x4 array of 32-bit integer values.</td>
1651 </tr>
1652 <tr class="layout">
1653 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1654 <td class="left">12x10 array of single precision floating point values.</td>
1655 </tr>
1656 <tr class="layout">
1657 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1658 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1659 </tr>
1660</table>
1661
Dan Gohman87ec5ad2009-11-09 19:01:53 +0000[diff] [blame]1662<p>There is no restriction on indexing beyond the end of the array implied by
1663 a static type (though there are restrictions on indexing beyond the bounds
1664 of an allocated object in some cases). This means that single-dimension
1665 'variable sized array' addressing can be implemented in LLVM with a zero
1666 length array type. An implementation of 'pascal style arrays' in LLVM could
1667 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1668
1669</div>
1670
1671<!-- _______________________________________________________________________ -->
1672<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1673
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1674<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1675
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1676<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1677<p>The function type can be thought of as a function signature. It consists of
1678 a return type and a list of formal parameter types. The return type of a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1679 function type is a scalar type, a void type, a struct type, or a union
1680 type. If the return type is a struct type then all struct elements must be
1681 of first class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1682
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1683<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1684<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1685 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1686</pre>
1687
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1688<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]1689 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1690 which indicates that the function takes a variable number of arguments.
1691 Variable argument functions can access their arguments with
1692 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1693 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1694 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1695
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1696<h5>Examples:</h5>
1697<table class="layout">
1698 <tr class="layout">
1699 <td class="left"><tt>i32 (i32)</tt></td>
1700 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1701 </td>
1702 </tr><tr class="layout">
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1703 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1704 </tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1705 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1706 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1707 returning <tt>float</tt>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1708 </td>
1709 </tr><tr class="layout">
1710 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1711 <td class="left">A vararg function that takes at least one
1712 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1713 which returns an integer. This is the signature for <tt>printf</tt> in
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1714 LLVM.
1715 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1716 </tr><tr class="layout">
1717 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1718 <td class="left">A function taking an <tt>i32</tt>, returning a
1719 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1720 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1721 </tr>
1722</table>
1723
1724</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1725
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1726<!-- _______________________________________________________________________ -->
1727<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1728
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1729<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1730
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1731<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1732<p>The structure type is used to represent a collection of data members together
1733 in memory. The packing of the field types is defined to match the ABI of the
1734 underlying processor. The elements of a structure may be any type that has a
1735 size.</p>
1736
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]1737<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1738 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1739 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1740 Structures in registers are accessed using the
1741 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1742 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
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 list&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">
1751 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1752 <td class="left">A triple of three <tt>i32</tt> values</td>
1753 </tr><tr class="layout">
1754 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1755 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1756 second element is a <a href="#t_pointer">pointer</a> to a
1757 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1758 an <tt>i32</tt>.</td>
1759 </tr>
1760</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1761
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1762</div>
1763
1764<!-- _______________________________________________________________________ -->
1765<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1766</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1767
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1768<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1769
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1770<h5>Overview:</h5>
1771<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1772 together in memory. There is no padding between fields. Further, the
1773 alignment of a packed structure is 1 byte. The elements of a packed
1774 structure may be any type that has a size.</p>
1775
1776<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1777 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1778 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1779
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1780<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1781<pre>
1782 &lt; { &lt;type list&gt; } &gt;
1783</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1784
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1785<h5>Examples:</h5>
1786<table class="layout">
1787 <tr class="layout">
1788 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1789 <td class="left">A triple of three <tt>i32</tt> values</td>
1790 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1791 <td class="left">
1792<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1793 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1794 second element is a <a href="#t_pointer">pointer</a> to a
1795 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1796 an <tt>i32</tt>.</td>
1797 </tr>
1798</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1799
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1800</div>
1801
1802<!-- _______________________________________________________________________ -->
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1803<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1804
1805<div class="doc_text">
1806
1807<h5>Overview:</h5>
1808<p>A union type describes an object with size and alignment suitable for
1809 an object of any one of a given set of types (also known as an "untagged"
1810 union). It is similar in concept and usage to a
1811 <a href="#t_struct">struct</a>, except that all members of the union
1812 have an offset of zero. The elements of a union may be any type that has a
1813 size. Unions must have at least one member - empty unions are not allowed.
1814 </p>
1815
1816<p>The size of the union as a whole will be the size of its largest member,
1817 and the alignment requirements of the union as a whole will be the largest
1818 alignment requirement of any member.</p>
1819
Dan Gohmanef8400c2010-02-25 16:51:31 +0000[diff] [blame]1820<p>Union members are accessed using '<tt><a href="#i_load">load</a></tt> and
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1821 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1822 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1823 Since all members are at offset zero, the getelementptr instruction does
1824 not affect the address, only the type of the resulting pointer.</p>
1825
1826<h5>Syntax:</h5>
1827<pre>
1828 union { &lt;type list&gt; }
1829</pre>
1830
1831<h5>Examples:</h5>
1832<table class="layout">
1833 <tr class="layout">
1834 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1835 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1836 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1837 </tr><tr class="layout">
1838 <td class="left">
1839 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1840 <td class="left">A union, where the first element is a <tt>float</tt> and the
1841 second element is a <a href="#t_pointer">pointer</a> to a
1842 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1843 an <tt>i32</tt>.</td>
1844 </tr>
1845</table>
1846
1847</div>
1848
1849<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1850<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1851
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1852<div class="doc_text">
1853
1854<h5>Overview:</h5>
Dan Gohmanb2f72c82010-02-25 16:50:07 +0000[diff] [blame]1855<p>The pointer type is used to specify memory locations.
1856 Pointers are commonly used to reference objects in memory.</p>
1857
1858<p>Pointer types may have an optional address space attribute defining the
1859 numbered address space where the pointed-to object resides. The default
1860 address space is number zero. The semantics of non-zero address
1861 spaces are target-specific.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1862
1863<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1864 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1865
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1866<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1867<pre>
1868 &lt;type&gt; *
1869</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1870
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1871<h5>Examples:</h5>
1872<table class="layout">
1873 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1874 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1875 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1876 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1877 </tr>
1878 <tr class="layout">
1879 <td class="left"><tt>i32 (i32 *) *</tt></td>
1880 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1881 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1882 <tt>i32</tt>.</td>
1883 </tr>
1884 <tr class="layout">
1885 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1886 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1887 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1888 </tr>
1889</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1890
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1891</div>
1892
1893<!-- _______________________________________________________________________ -->
1894<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1895
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1896<div class="doc_text">
1897
1898<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1899<p>A vector type is a simple derived type that represents a vector of elements.
1900 Vector types are used when multiple primitive data are operated in parallel
1901 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands87598b02009-11-27 13:38:03 +0000[diff] [blame]1902 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1903 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1904
1905<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1906<pre>
1907 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1908</pre>
1909
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1910<p>The number of elements is a constant integer value; elementtype may be any
1911 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1912
1913<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1914<table class="layout">
1915 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1916 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1917 <td class="left">Vector of 4 32-bit integer values.</td>
1918 </tr>
1919 <tr class="layout">
1920 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1921 <td class="left">Vector of 8 32-bit floating-point values.</td>
1922 </tr>
1923 <tr class="layout">
1924 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1925 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1926 </tr>
1927</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1928
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1929</div>
1930
1931<!-- _______________________________________________________________________ -->
1932<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1933<div class="doc_text">
1934
1935<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1936<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1937 corresponds (for example) to the C notion of a forward declared structure
1938 type. In LLVM, opaque types can eventually be resolved to any type (not just
1939 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1940
1941<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1942<pre>
1943 opaque
1944</pre>
1945
1946<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1947<table class="layout">
1948 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1949 <td class="left"><tt>opaque</tt></td>
1950 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1951 </tr>
1952</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1953
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1954</div>
1955
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1956<!-- ======================================================================= -->
1957<div class="doc_subsection">
1958 <a name="t_uprefs">Type Up-references</a>
1959</div>
1960
1961<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1962
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1963<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1964<p>An "up reference" allows you to refer to a lexically enclosing type without
1965 requiring it to have a name. For instance, a structure declaration may
1966 contain a pointer to any of the types it is lexically a member of. Example
1967 of up references (with their equivalent as named type declarations)
1968 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1969
1970<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1971 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1972 { \2 }* %y = type { %y }*
1973 \1* %z = type %z*
1974</pre>
1975
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1976<p>An up reference is needed by the asmprinter for printing out cyclic types
1977 when there is no declared name for a type in the cycle. Because the
1978 asmprinter does not want to print out an infinite type string, it needs a
1979 syntax to handle recursive types that have no names (all names are optional
1980 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1981
1982<h5>Syntax:</h5>
1983<pre>
1984 \&lt;level&gt;
1985</pre>
1986
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1987<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]1988
1989<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1990<table class="layout">
1991 <tr class="layout">
1992 <td class="left"><tt>\1*</tt></td>
1993 <td class="left">Self-referential pointer.</td>
1994 </tr>
1995 <tr class="layout">
1996 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1997 <td class="left">Recursive structure where the upref refers to the out-most
1998 structure.</td>
1999 </tr>
2000</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2001
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2002</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2003
2004<!-- *********************************************************************** -->
2005<div class="doc_section"> <a name="constants">Constants</a> </div>
2006<!-- *********************************************************************** -->
2007
2008<div class="doc_text">
2009
2010<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2011 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2012
2013</div>
2014
2015<!-- ======================================================================= -->
2016<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
2017
2018<div class="doc_text">
2019
2020<dl>
2021 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2022 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]2023 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2024
2025 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2026 <dd>Standard integers (such as '4') are constants of
2027 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2028 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2029
2030 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2031 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2032 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2033 notation (see below). The assembler requires the exact decimal value of a
2034 floating-point constant. For example, the assembler accepts 1.25 but
2035 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2036 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2037
2038 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2039 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2040 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2041</dl>
2042
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2043<p>The one non-intuitive notation for constants is the hexadecimal form of
2044 floating point constants. For example, the form '<tt>double
2045 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2046 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2047 constants are required (and the only time that they are generated by the
2048 disassembler) is when a floating point constant must be emitted but it cannot
2049 be represented as a decimal floating point number in a reasonable number of
2050 digits. For example, NaN's, infinities, and other special values are
2051 represented in their IEEE hexadecimal format so that assembly and disassembly
2052 do not cause any bits to change in the constants.</p>
2053
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]2054<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2055 represented using the 16-digit form shown above (which matches the IEEE754
2056 representation for double); float values must, however, be exactly
2057 representable as IEE754 single precision. Hexadecimal format is always used
2058 for long double, and there are three forms of long double. The 80-bit format
2059 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2060 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2061 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2062 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2063 currently supported target uses this format. Long doubles will only work if
2064 they match the long double format on your target. All hexadecimal formats
2065 are big-endian (sign bit at the left).</p>
2066
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2067</div>
2068
2069<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2070<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2071<a name="aggregateconstants"></a> <!-- old anchor -->
2072<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2073</div>
2074
2075<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2076
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2077<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2078 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2079
2080<dl>
2081 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2082 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2083 type definitions (a comma separated list of elements, surrounded by braces
2084 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2085 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2086 Structure constants must have <a href="#t_struct">structure type</a>, and
2087 the number and types of elements must match those specified by the
2088 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2089
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2090 <dt><b>Union constants</b></dt>
2091 <dd>Union constants are represented with notation similar to a structure with
2092 a single element - that is, a single typed element surrounded
2093 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2094 <a href="#t_union">union type</a> can be initialized with a single-element
2095 struct as long as the type of the struct element matches the type of
2096 one of the union members.</dd>
2097
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2098 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2099 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2100 definitions (a comma separated list of elements, surrounded by square
2101 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2102 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2103 the number and types of elements must match those specified by the
2104 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2105
2106 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2107 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2108 definitions (a comma separated list of elements, surrounded by
2109 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2110 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2111 have <a href="#t_vector">vector type</a>, and the number and types of
2112 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2113
2114 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2115 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2116 value to zero of <em>any</em> type, including scalar and
2117 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2118 This is often used to avoid having to print large zero initializers
2119 (e.g. for large arrays) and is always exactly equivalent to using explicit
2120 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2121
2122 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]2123 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2124 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2125 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2126 be interpreted as part of the instruction stream, metadata is a place to
2127 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2128</dl>
2129
2130</div>
2131
2132<!-- ======================================================================= -->
2133<div class="doc_subsection">
2134 <a name="globalconstants">Global Variable and Function Addresses</a>
2135</div>
2136
2137<div class="doc_text">
2138
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2139<p>The addresses of <a href="#globalvars">global variables</a>
2140 and <a href="#functionstructure">functions</a> are always implicitly valid
2141 (link-time) constants. These constants are explicitly referenced when
2142 the <a href="#identifiers">identifier for the global</a> is used and always
2143 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2144 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2145
2146<div class="doc_code">
2147<pre>
2148@X = global i32 17
2149@Y = global i32 42
2150@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2151</pre>
2152</div>
2153
2154</div>
2155
2156<!-- ======================================================================= -->
2157<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2158<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2159
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2160<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]2161 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2162 Undefined values may be of any type (other than label or void) and be used
2163 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2164
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2165<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2166 program is well defined no matter what value is used. This gives the
2167 compiler more freedom to optimize. Here are some examples of (potentially
2168 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2169
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2170
2171<div class="doc_code">
2172<pre>
2173 %A = add %X, undef
2174 %B = sub %X, undef
2175 %C = xor %X, undef
2176Safe:
2177 %A = undef
2178 %B = undef
2179 %C = undef
2180</pre>
2181</div>
2182
2183<p>This is safe because all of the output bits are affected by the undef bits.
2184Any output bit can have a zero or one depending on the input bits.</p>
2185
2186<div class="doc_code">
2187<pre>
2188 %A = or %X, undef
2189 %B = and %X, undef
2190Safe:
2191 %A = -1
2192 %B = 0
2193Unsafe:
2194 %A = undef
2195 %B = undef
2196</pre>
2197</div>
2198
2199<p>These logical operations have bits that are not always affected by the input.
2200For example, if "%X" has a zero bit, then the output of the 'and' operation will
2201always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2202such, it is unsafe to optimize or assume that the result of the and is undef.
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2203However, it is safe to assume that all bits of the undef could be 0, and
2204optimize the and to 0. Likewise, it is safe to assume that all the bits of
2205the undef operand to the or could be set, allowing the or to be folded to
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2206-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2207
2208<div class="doc_code">
2209<pre>
2210 %A = select undef, %X, %Y
2211 %B = select undef, 42, %Y
2212 %C = select %X, %Y, undef
2213Safe:
2214 %A = %X (or %Y)
2215 %B = 42 (or %Y)
2216 %C = %Y
2217Unsafe:
2218 %A = undef
2219 %B = undef
2220 %C = undef
2221</pre>
2222</div>
2223
2224<p>This set of examples show that undefined select (and conditional branch)
2225conditions can go "either way" but they have to come from one of the two
2226operands. In the %A example, if %X and %Y were both known to have a clear low
2227bit, then %A would have to have a cleared low bit. However, in the %C example,
2228the optimizer is allowed to assume that the undef operand could be the same as
2229%Y, allowing the whole select to be eliminated.</p>
2230
2231
2232<div class="doc_code">
2233<pre>
2234 %A = xor undef, undef
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2235
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2236 %B = undef
2237 %C = xor %B, %B
2238
2239 %D = undef
2240 %E = icmp lt %D, 4
2241 %F = icmp gte %D, 4
2242
2243Safe:
2244 %A = undef
2245 %B = undef
2246 %C = undef
2247 %D = undef
2248 %E = undef
2249 %F = undef
2250</pre>
2251</div>
2252
2253<p>This example points out that two undef operands are not necessarily the same.
2254This can be surprising to people (and also matches C semantics) where they
2255assume that "X^X" is always zero, even if X is undef. This isn't true for a
2256number of reasons, but the short answer is that an undef "variable" can
2257arbitrarily change its value over its "live range". This is true because the
2258"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2259logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2260so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2261to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2262would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2263
2264<div class="doc_code">
2265<pre>
2266 %A = fdiv undef, %X
2267 %B = fdiv %X, undef
2268Safe:
2269 %A = undef
2270b: unreachable
2271</pre>
2272</div>
2273
2274<p>These examples show the crucial difference between an <em>undefined
2275value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2276allowed to have an arbitrary bit-pattern. This means that the %A operation
2277can be constant folded to undef because the undef could be an SNaN, and fdiv is
2278not (currently) defined on SNaN's. However, in the second example, we can make
2279a more aggressive assumption: because the undef is allowed to be an arbitrary
2280value, 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]2281has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2282does not execute at all. This allows us to delete the divide and all code after
2283it: since the undefined operation "can't happen", the optimizer can assume that
2284it occurs in dead code.
2285</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2286
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2287<div class="doc_code">
2288<pre>
2289a: store undef -> %X
2290b: store %X -> undef
2291Safe:
2292a: &lt;deleted&gt;
2293b: unreachable
2294</pre>
2295</div>
2296
2297<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2298can be assumed to not have any effect: we can assume that the value is
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2299overwritten with bits that happen to match what was already there. However, a
2300store "to" an undefined location could clobber arbitrary memory, therefore, it
2301has undefined behavior.</p>
2302
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2303</div>
2304
2305<!-- ======================================================================= -->
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2306<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2307 Blocks</a></div>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2308<div class="doc_text">
2309
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2310<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2311
2312<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner24f2e852009-10-27 21:49:40 +0000[diff] [blame]2313 basic block in the specified function, and always has an i8* type. Taking
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2314 the address of the entry block is illegal.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2315
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2316<p>This value only has defined behavior when used as an operand to the
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2317 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2318 against null. Pointer equality tests between labels addresses is undefined
2319 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2320 equal to the null pointer. This may also be passed around as an opaque
2321 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner0bae7b32009-10-27 21:44:20 +0000[diff] [blame]2322 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2323 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2324
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2325<p>Finally, some targets may provide defined semantics when
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2326 using the value as the operand to an inline assembly, but that is target
2327 specific.
2328 </p>
2329
2330</div>
2331
2332
2333<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2334<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2335</div>
2336
2337<div class="doc_text">
2338
2339<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2340 to be used as constants. Constant expressions may be of
2341 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2342 operation that does not have side effects (e.g. load and call are not
2343 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2344
2345<dl>
2346 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2347 <dd>Truncate a constant to another type. The bit size of CST must be larger
2348 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2349
2350 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2351 <dd>Zero extend a constant to another type. The bit size of CST must be
2352 smaller or equal to the bit size of TYPE. Both types must be
2353 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2354
2355 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2356 <dd>Sign extend a constant to another type. The bit size of CST must be
2357 smaller or equal to the bit size of TYPE. Both types must be
2358 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2359
2360 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2361 <dd>Truncate a floating point constant to another floating point type. The
2362 size of CST must be larger than the size of TYPE. Both types must be
2363 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2364
2365 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2366 <dd>Floating point extend a constant to another type. The size of CST must be
2367 smaller or equal to the size of TYPE. Both types must be floating
2368 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2369
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2370 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2371 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2372 constant. TYPE must be a scalar or vector integer type. CST must be of
2373 scalar or vector floating point type. Both CST and TYPE must be scalars,
2374 or vectors of the same number of elements. If the value won't fit in the
2375 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2376
2377 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2378 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2379 constant. TYPE must be a scalar or vector integer type. CST must be of
2380 scalar or vector floating point type. Both CST and TYPE must be scalars,
2381 or vectors of the same number of elements. If the value won't fit in the
2382 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2383
2384 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2385 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2386 constant. TYPE must be a scalar or vector floating point type. CST must be
2387 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2388 vectors of the same number of elements. If the value won't fit in the
2389 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2390
2391 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2392 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2393 constant. TYPE must be a scalar or vector floating point type. CST must be
2394 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2395 vectors of the same number of elements. If the value won't fit in the
2396 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2397
2398 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2399 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2400 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2401 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2402 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2403
2404 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2405 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2406 type. CST must be of integer type. The CST value is zero extended,
2407 truncated, or unchanged to make it fit in a pointer size. This one is
2408 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2409
2410 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2411 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2412 are the same as those for the <a href="#i_bitcast">bitcast
2413 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2414
2415 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2416 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2417 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2418 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2419 instruction, the index list may have zero or more indexes, which are
2420 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2421
2422 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2423 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2424
2425 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2426 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2427
2428 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2429 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2430
2431 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2432 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2433 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2434
2435 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2436 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2437 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2438
2439 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2440 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2441 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2442
2443 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2444 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2445 be any of the <a href="#binaryops">binary</a>
2446 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2447 on operands are the same as those for the corresponding instruction
2448 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2449</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2450
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2451</div>
2452
2453<!-- *********************************************************************** -->
2454<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2455<!-- *********************************************************************** -->
2456
2457<!-- ======================================================================= -->
2458<div class="doc_subsection">
2459<a name="inlineasm">Inline Assembler Expressions</a>
2460</div>
2461
2462<div class="doc_text">
2463
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2464<p>LLVM supports inline assembler expressions (as opposed
2465 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2466 a special value. This value represents the inline assembler as a string
2467 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2468 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2469 expression has side effects, and a flag indicating whether the function
2470 containing the asm needs to align its stack conservatively. An example
2471 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2472
2473<div class="doc_code">
2474<pre>
2475i32 (i32) asm "bswap $0", "=r,r"
2476</pre>
2477</div>
2478
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2479<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2480 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2481 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2482
2483<div class="doc_code">
2484<pre>
2485%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2486</pre>
2487</div>
2488
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2489<p>Inline asms with side effects not visible in the constraint list must be
2490 marked as having side effects. This is done through the use of the
2491 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2492
2493<div class="doc_code">
2494<pre>
2495call void asm sideeffect "eieio", ""()
2496</pre>
2497</div>
2498
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2499<p>In some cases inline asms will contain code that will not work unless the
2500 stack is aligned in some way, such as calls or SSE instructions on x86,
2501 yet will not contain code that does that alignment within the asm.
2502 The compiler should make conservative assumptions about what the asm might
2503 contain and should generate its usual stack alignment code in the prologue
2504 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2505
2506<div class="doc_code">
2507<pre>
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2508call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2509</pre>
2510</div>
2511
2512<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2513 first.</p>
2514
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2515<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2516 documented here. Constraints on what can be done (e.g. duplication, moving,
2517 etc need to be documented). This is probably best done by reference to
2518 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2519
2520</div>
2521
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2522<!-- ======================================================================= -->
2523<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2524 Strings</a>
2525</div>
2526
2527<div class="doc_text">
2528
2529<p>LLVM IR allows metadata to be attached to instructions in the program that
2530 can convey extra information about the code to the optimizers and code
2531 generator. One example application of metadata is source-level debug
2532 information. There are two metadata primitives: strings and nodes. All
2533 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2534 preceding exclamation point ('<tt>!</tt>').</p>
2535
2536<p>A metadata string is a string surrounded by double quotes. It can contain
2537 any character by escaping non-printable characters with "\xx" where "xx" is
2538 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2539
2540<p>Metadata nodes are represented with notation similar to structure constants
2541 (a comma separated list of elements, surrounded by braces and preceded by an
2542 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2543 10}</tt>". Metadata nodes can have any values as their operand.</p>
2544
2545<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2546 metadata nodes, which can be looked up in the module symbol table. For
2547 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2548
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2549<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
2550 function is using two metadata arguments.
2551
2552 <div class="doc_code">
2553 <pre>
2554 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2555 </pre>
2556 </div></p>
2557
2558<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
2559 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.
2560
2561 <div class="doc_code">
2562 <pre>
2563 %indvar.next = add i64 %indvar, 1, !dbg !21
2564 </pre>
2565 </div></p>
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2566</div>
2567
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2568
2569<!-- *********************************************************************** -->
2570<div class="doc_section">
2571 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2572</div>
2573<!-- *********************************************************************** -->
2574
2575<p>LLVM has a number of "magic" global variables that contain data that affect
2576code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2577of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2578section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2579by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2580
2581<!-- ======================================================================= -->
2582<div class="doc_subsection">
2583<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2584</div>
2585
2586<div class="doc_text">
2587
2588<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2589href="#linkage_appending">appending linkage</a>. This array contains a list of
2590pointers to global variables and functions which may optionally have a pointer
2591cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2592
2593<pre>
2594 @X = global i8 4
2595 @Y = global i32 123
2596
2597 @llvm.used = appending global [2 x i8*] [
2598 i8* @X,
2599 i8* bitcast (i32* @Y to i8*)
2600 ], section "llvm.metadata"
2601</pre>
2602
2603<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2604compiler, assembler, and linker are required to treat the symbol as if there is
2605a reference to the global that it cannot see. For example, if a variable has
2606internal linkage and no references other than that from the <tt>@llvm.used</tt>
2607list, it cannot be deleted. This is commonly used to represent references from
2608inline asms and other things the compiler cannot "see", and corresponds to
2609"attribute((used))" in GNU C.</p>
2610
2611<p>On some targets, the code generator must emit a directive to the assembler or
2612object file to prevent the assembler and linker from molesting the symbol.</p>
2613
2614</div>
2615
2616<!-- ======================================================================= -->
2617<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2618<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2619</div>
2620
2621<div class="doc_text">
2622
2623<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2624<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2625touching the symbol. On targets that support it, this allows an intelligent
2626linker to optimize references to the symbol without being impeded as it would be
2627by <tt>@llvm.used</tt>.</p>
2628
2629<p>This is a rare construct that should only be used in rare circumstances, and
2630should not be exposed to source languages.</p>
2631
2632</div>
2633
2634<!-- ======================================================================= -->
2635<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2636<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2637</div>
2638
2639<div class="doc_text">
2640
2641<p>TODO: Describe this.</p>
2642
2643</div>
2644
2645<!-- ======================================================================= -->
2646<div class="doc_subsection">
2647<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2648</div>
2649
2650<div class="doc_text">
2651
2652<p>TODO: Describe this.</p>
2653
2654</div>
2655
2656
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2657<!-- *********************************************************************** -->
2658<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2659<!-- *********************************************************************** -->
2660
2661<div class="doc_text">
2662
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2663<p>The LLVM instruction set consists of several different classifications of
2664 instructions: <a href="#terminators">terminator
2665 instructions</a>, <a href="#binaryops">binary instructions</a>,
2666 <a href="#bitwiseops">bitwise binary instructions</a>,
2667 <a href="#memoryops">memory instructions</a>, and
2668 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2669
2670</div>
2671
2672<!-- ======================================================================= -->
2673<div class="doc_subsection"> <a name="terminators">Terminator
2674Instructions</a> </div>
2675
2676<div class="doc_text">
2677
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2678<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2679 in a program ends with a "Terminator" instruction, which indicates which
2680 block should be executed after the current block is finished. These
2681 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2682 control flow, not values (the one exception being the
2683 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2684
2685<p>There are six different terminator instructions: the
2686 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2687 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2688 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendlingb4ae2292009-11-02 00:25:26 +0000[diff] [blame]2689 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2690 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2691 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2692 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2693
2694</div>
2695
2696<!-- _______________________________________________________________________ -->
2697<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2698Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2699
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2700<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2701
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2702<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2703<pre>
2704 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]2705 ret void <i>; Return from void function</i>
2706</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2707
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2708<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2709<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2710 a value) from a function back to the caller.</p>
2711
2712<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2713 value and then causes control flow, and one that just causes control flow to
2714 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2715
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2716<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2717<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2718 return value. The type of the return value must be a
2719 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2720
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2721<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2722 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2723 value or a return value with a type that does not match its type, or if it
2724 has a void return type and contains a '<tt>ret</tt>' instruction with a
2725 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2726
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2727<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2728<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2729 the calling function's context. If the caller is a
2730 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2731 instruction after the call. If the caller was an
2732 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2733 the beginning of the "normal" destination block. If the instruction returns
2734 a value, that value shall set the call or invoke instruction's return
2735 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2736
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2737<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2738<pre>
2739 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2740 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2741 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]2742</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2743
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2744</div>
2745<!-- _______________________________________________________________________ -->
2746<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2747
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2748<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2749
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2750<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2751<pre>
2752 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]2753</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2754
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2755<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2756<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2757 different basic block in the current function. There are two forms of this
2758 instruction, corresponding to a conditional branch and an unconditional
2759 branch.</p>
2760
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2761<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2762<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2763 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2764 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2765 target.</p>
2766
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2767<h5>Semantics:</h5>
2768<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2769 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2770 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2771 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2772
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2773<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2774<pre>
2775Test:
2776 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2777 br i1 %cond, label %IfEqual, label %IfUnequal
2778IfEqual:
2779 <a href="#i_ret">ret</a> i32 1
2780IfUnequal:
2781 <a href="#i_ret">ret</a> i32 0
2782</pre>
2783
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2784</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2785
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2786<!-- _______________________________________________________________________ -->
2787<div class="doc_subsubsection">
2788 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2789</div>
2790
2791<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2792
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2793<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2794<pre>
2795 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2796</pre>
2797
2798<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2799<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]2800 several different places. It is a generalization of the '<tt>br</tt>'
2801 instruction, allowing a branch to occur to one of many possible
2802 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2803
2804<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2805<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2806 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2807 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2808 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2809
2810<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2811<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2812 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2813 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2814 transferred to the corresponding destination; otherwise, control flow is
2815 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2816
2817<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2818<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2819 <tt>switch</tt> instruction, this instruction may be code generated in
2820 different ways. For example, it could be generated as a series of chained
2821 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2822
2823<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2824<pre>
2825 <i>; Emulate a conditional br instruction</i>
2826 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2827 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2828
2829 <i>; Emulate an unconditional br instruction</i>
2830 switch i32 0, label %dest [ ]
2831
2832 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2833 switch i32 %val, label %otherwise [ i32 0, label %onzero
2834 i32 1, label %onone
2835 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2836</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2838</div>
2839
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2840
2841<!-- _______________________________________________________________________ -->
2842<div class="doc_subsubsection">
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2843 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2844</div>
2845
2846<div class="doc_text">
2847
2848<h5>Syntax:</h5>
2849<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2850 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]2851</pre>
2852
2853<h5>Overview:</h5>
2854
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2855<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2856 within the current function, whose address is specified by
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2857 "<tt>address</tt>". Address must be derived from a <a
2858 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2859
2860<h5>Arguments:</h5>
2861
2862<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2863 rest of the arguments indicate the full set of possible destinations that the
2864 address may point to. Blocks are allowed to occur multiple times in the
2865 destination list, though this isn't particularly useful.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2866
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2867<p>This destination list is required so that dataflow analysis has an accurate
2868 understanding of the CFG.</p>
2869
2870<h5>Semantics:</h5>
2871
2872<p>Control transfers to the block specified in the address argument. All
2873 possible destination blocks must be listed in the label list, otherwise this
2874 instruction has undefined behavior. This implies that jumps to labels
2875 defined in other functions have undefined behavior as well.</p>
2876
2877<h5>Implementation:</h5>
2878
2879<p>This is typically implemented with a jump through a register.</p>
2880
2881<h5>Example:</h5>
2882<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2883 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2884</pre>
2885
2886</div>
2887
2888
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2889<!-- _______________________________________________________________________ -->
2890<div class="doc_subsubsection">
2891 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2892</div>
2893
2894<div class="doc_text">
2895
2896<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2897<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2898 &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]2899 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2900</pre>
2901
2902<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2903<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2904 function, with the possibility of control flow transfer to either the
2905 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2906 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2907 control flow will return to the "normal" label. If the callee (or any
2908 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2909 instruction, control is interrupted and continued at the dynamically nearest
2910 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2911
2912<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2913<p>This instruction requires several arguments:</p>
2914
2915<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2916 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2917 convention</a> the call should use. If none is specified, the call
2918 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2919
2920 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2921 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2922 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2923
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2924 <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]2925 function value being invoked. In most cases, this is a direct function
2926 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2927 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2928
2929 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2930 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2931
2932 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]2933 signature argument types and parameter attributes. All arguments must be
2934 of <a href="#t_firstclass">first class</a> type. If the function
2935 signature indicates the function accepts a variable number of arguments,
2936 the extra arguments can be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2937
2938 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2939 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2940
2941 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2942 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2943
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2944 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2945 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2946 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2947</ol>
2948
2949<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2950<p>This instruction is designed to operate as a standard
2951 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2952 primary difference is that it establishes an association with a label, which
2953 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2954
2955<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2956 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2957 exception. Additionally, this is important for implementation of
2958 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2959
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2960<p>For the purposes of the SSA form, the definition of the value returned by the
2961 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2962 block to the "normal" label. If the callee unwinds then no return value is
2963 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2964
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]2965<p>Note that the code generator does not yet completely support unwind, and
2966that the invoke/unwind semantics are likely to change in future versions.</p>
2967
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2968<h5>Example:</h5>
2969<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2970 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2971 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2972 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2973 unwind label %TestCleanup <i>; {i32}:retval set</i>
2974</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2975
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2976</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2977
2978<!-- _______________________________________________________________________ -->
2979
2980<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2981Instruction</a> </div>
2982
2983<div class="doc_text">
2984
2985<h5>Syntax:</h5>
2986<pre>
2987 unwind
2988</pre>
2989
2990<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2991<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2992 at the first callee in the dynamic call stack which used
2993 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2994 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2995
2996<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2997<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2998 immediately halt. The dynamic call stack is then searched for the
2999 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3000 Once found, execution continues at the "exceptional" destination block
3001 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3002 instruction in the dynamic call chain, undefined behavior results.</p>
3003
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]3004<p>Note that the code generator does not yet completely support unwind, and
3005that the invoke/unwind semantics are likely to change in future versions.</p>
3006
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3007</div>
3008
3009<!-- _______________________________________________________________________ -->
3010
3011<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3012Instruction</a> </div>
3013
3014<div class="doc_text">
3015
3016<h5>Syntax:</h5>
3017<pre>
3018 unreachable
3019</pre>
3020
3021<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3022<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3023 instruction is used to inform the optimizer that a particular portion of the
3024 code is not reachable. This can be used to indicate that the code after a
3025 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3026
3027<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3028<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3029
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3030</div>
3031
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3032<!-- ======================================================================= -->
3033<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3034
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3035<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3036
3037<p>Binary operators are used to do most of the computation in a program. They
3038 require two operands of the same type, execute an operation on them, and
3039 produce a single value. The operands might represent multiple data, as is
3040 the case with the <a href="#t_vector">vector</a> data type. The result value
3041 has the same type as its operands.</p>
3042
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3043<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3044
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3045</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3046
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3047<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3048<div class="doc_subsubsection">
3049 <a name="i_add">'<tt>add</tt>' Instruction</a>
3050</div>
3051
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3052<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3053
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3054<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3055<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3056 &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]3057 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3058 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3059 &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]3060</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3061
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3062<h5>Overview:</h5>
3063<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3064
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3065<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3066<p>The two arguments to the '<tt>add</tt>' instruction must
3067 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3068 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3069
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3070<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3071<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3072
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3073<p>If the sum has unsigned overflow, the result returned is the mathematical
3074 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]3075
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3076<p>Because LLVM integers use a two's complement representation, this instruction
3077 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3078
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3079<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3080 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3081 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
3082 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3083
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3084<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3085<pre>
3086 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3087</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3088
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3089</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3090
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3091<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3092<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3093 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3094</div>
3095
3096<div class="doc_text">
3097
3098<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3099<pre>
3100 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3101</pre>
3102
3103<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3104<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3105
3106<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3107<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3108 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3109 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3110
3111<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3112<p>The value produced is the floating point sum of the two operands.</p>
3113
3114<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3115<pre>
3116 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3117</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3118
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3119</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3120
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3121<!-- _______________________________________________________________________ -->
3122<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3123 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3124</div>
3125
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3126<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3127
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3128<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3129<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3130 &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]3131 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3132 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3133 &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]3134</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3135
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3136<h5>Overview:</h5>
3137<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3138 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3139
3140<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3141 '<tt>neg</tt>' instruction present in most other intermediate
3142 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3143
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3144<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3145<p>The two arguments to the '<tt>sub</tt>' instruction must
3146 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3147 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3148
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3149<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3150<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3151
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3152<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3153 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3154 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3155
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3156<p>Because LLVM integers use a two's complement representation, this instruction
3157 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3158
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3159<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3160 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3161 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
3162 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3163
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3164<h5>Example:</h5>
3165<pre>
3166 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
3167 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
3168</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3169
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3170</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3171
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3172<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3173<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3174 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3175</div>
3176
3177<div class="doc_text">
3178
3179<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3180<pre>
3181 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3182</pre>
3183
3184<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3185<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3186 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3187
3188<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3189 '<tt>fneg</tt>' instruction present in most other intermediate
3190 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3191
3192<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]3193<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3194 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3195 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3196
3197<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3198<p>The value produced is the floating point difference of the two operands.</p>
3199
3200<h5>Example:</h5>
3201<pre>
3202 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3203 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3204</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3205
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3206</div>
3207
3208<!-- _______________________________________________________________________ -->
3209<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3210 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3211</div>
3212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3213<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3214
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3215<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3216<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3217 &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]3218 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3219 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3220 &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]3221</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3222
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3223<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3224<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3225
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3226<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3227<p>The two arguments to the '<tt>mul</tt>' instruction must
3228 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3229 integer values. Both arguments must have identical types.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3230
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3231<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3232<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3233
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3234<p>If the result of the multiplication has unsigned overflow, the result
3235 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3236 width of the result.</p>
3237
3238<p>Because LLVM integers use a two's complement representation, and the result
3239 is the same width as the operands, this instruction returns the correct
3240 result for both signed and unsigned integers. If a full product
3241 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3242 be sign-extended or zero-extended as appropriate to the width of the full
3243 product.</p>
3244
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3245<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3246 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3247 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3248 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3249
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3250<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3251<pre>
3252 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3253</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3254
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3255</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3256
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3257<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3258<div class="doc_subsubsection">
3259 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3260</div>
3261
3262<div class="doc_text">
3263
3264<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3265<pre>
3266 &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]3267</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3268
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3269<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3270<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3271
3272<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3273<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3274 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3275 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3276
3277<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3278<p>The value produced is the floating point product of the two operands.</p>
3279
3280<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3281<pre>
3282 &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]3283</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3284
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3285</div>
3286
3287<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3288<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3289</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3290
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3291<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3292
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3293<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3294<pre>
3295 &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]3296</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3298<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3299<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3300
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3301<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3302<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3303 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3304 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3305
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3306<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3307<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3308
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3309<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3310 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3311
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3312<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3313
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3314<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3315<pre>
3316 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3317</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3318
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3319</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3320
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3321<!-- _______________________________________________________________________ -->
3322<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3323</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3324
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3325<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3326
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3327<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3328<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3329 &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]3330 &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]3331</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3332
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3333<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3334<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3335
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3336<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3337<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3338 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3339 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3340
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3341<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3342<p>The value produced is the signed integer quotient of the two operands rounded
3343 towards zero.</p>
3344
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3345<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3346 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3347
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3348<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3349 undefined behavior; this is a rare case, but can occur, for example, by doing
3350 a 32-bit division of -2147483648 by -1.</p>
3351
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3352<p>If the <tt>exact</tt> keyword is present, the result value of the
3353 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3354 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3355
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3356<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3357<pre>
3358 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3359</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3360
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3361</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3362
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3363<!-- _______________________________________________________________________ -->
3364<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3365Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3366
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3367<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3368
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3369<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3370<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3371 &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]3372</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3373
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3374<h5>Overview:</h5>
3375<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3376
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3377<h5>Arguments:</h5>
3378<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3379 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3380 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3381
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3382<h5>Semantics:</h5>
3383<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3384
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3385<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3386<pre>
3387 &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]3388</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3390</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3391
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3392<!-- _______________________________________________________________________ -->
3393<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3394</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3395
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3396<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3397
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3398<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3399<pre>
3400 &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]3401</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3402
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3403<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3404<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3405 division of its two arguments.</p>
3406
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3407<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3408<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3409 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3410 values. Both arguments must have identical types.</p>
3411
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3412<h5>Semantics:</h5>
3413<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3414 This instruction always performs an unsigned division to get the
3415 remainder.</p>
3416
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3417<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3418 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3419
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3420<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3421
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3422<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3423<pre>
3424 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3425</pre>
3426
3427</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3428
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3429<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3430<div class="doc_subsubsection">
3431 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3432</div>
3433
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3434<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3435
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3436<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3437<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3438 &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]3439</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3440
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3441<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3442<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3443 division of its two operands. This instruction can also take
3444 <a href="#t_vector">vector</a> versions of the values in which case the
3445 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3446
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3447<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3448<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3449 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3450 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3451
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3452<h5>Semantics:</h5>
3453<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3454 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3455 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3456 a value. For more information about the difference,
3457 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3458 Math Forum</a>. For a table of how this is implemented in various languages,
3459 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3460 Wikipedia: modulo operation</a>.</p>
3461
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3462<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3463 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3464
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3465<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3466 Overflow also leads to undefined behavior; this is a rare case, but can
3467 occur, for example, by taking the remainder of a 32-bit division of
3468 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3469 lets srem be implemented using instructions that return both the result of
3470 the division and the remainder.)</p>
3471
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3472<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3473<pre>
3474 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3475</pre>
3476
3477</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3478
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3479<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3480<div class="doc_subsubsection">
3481 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3482
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3483<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3484
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3485<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3486<pre>
3487 &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]3488</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3489
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3490<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3491<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3492 its two operands.</p>
3493
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3494<h5>Arguments:</h5>
3495<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3496 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3497 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3498
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3499<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3500<p>This instruction returns the <i>remainder</i> of a division. The remainder
3501 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3502
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3503<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3504<pre>
3505 &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]3506</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3507
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3508</div>
3509
3510<!-- ======================================================================= -->
3511<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3512Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3513
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3514<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3515
3516<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3517 program. They are generally very efficient instructions and can commonly be
3518 strength reduced from other instructions. They require two operands of the
3519 same type, execute an operation on them, and produce a single value. The
3520 resulting value is the same type as its operands.</p>
3521
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3522</div>
3523
3524<!-- _______________________________________________________________________ -->
3525<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3526Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3527
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3528<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3530<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3531<pre>
3532 &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]3533</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3534
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3535<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3536<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3537 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3538
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3539<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3540<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3541 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3542 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3543
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3544<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3545<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3546 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3547 is (statically or dynamically) negative or equal to or larger than the number
3548 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3549 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3550 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3551
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3552<h5>Example:</h5>
3553<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3554 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3555 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3556 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3557 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3558 &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]3559</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3560
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3561</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3562
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3563<!-- _______________________________________________________________________ -->
3564<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3565Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3566
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3567<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3568
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3569<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3570<pre>
3571 &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]3572</pre>
3573
3574<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3575<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3576 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3577
3578<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3579<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
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 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3582
3583<h5>Semantics:</h5>
3584<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3585 significant bits of the result will be filled with zero bits after the shift.
3586 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3587 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3588 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3589 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3590
3591<h5>Example:</h5>
3592<pre>
3593 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3594 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3595 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3596 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3597 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3598 &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]3599</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3601</div>
3602
3603<!-- _______________________________________________________________________ -->
3604<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3605Instruction</a> </div>
3606<div class="doc_text">
3607
3608<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3609<pre>
3610 &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]3611</pre>
3612
3613<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3614<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3615 operand shifted to the right a specified number of bits with sign
3616 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3617
3618<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3619<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3620 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3621 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3622
3623<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3624<p>This instruction always performs an arithmetic shift right operation, The
3625 most significant bits of the result will be filled with the sign bit
3626 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3627 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3628 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3629 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3630
3631<h5>Example:</h5>
3632<pre>
3633 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3634 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3635 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3636 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3637 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3638 &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]3639</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3640
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3641</div>
3642
3643<!-- _______________________________________________________________________ -->
3644<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3645Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3646
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3647<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3648
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3649<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3650<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3651 &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]3652</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3653
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3654<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3655<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3656 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3657
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3658<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3659<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3660 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3661 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3663<h5>Semantics:</h5>
3664<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3665
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3666<table border="1" cellspacing="0" cellpadding="4">
3667 <tbody>
3668 <tr>
3669 <td>In0</td>
3670 <td>In1</td>
3671 <td>Out</td>
3672 </tr>
3673 <tr>
3674 <td>0</td>
3675 <td>0</td>
3676 <td>0</td>
3677 </tr>
3678 <tr>
3679 <td>0</td>
3680 <td>1</td>
3681 <td>0</td>
3682 </tr>
3683 <tr>
3684 <td>1</td>
3685 <td>0</td>
3686 <td>0</td>
3687 </tr>
3688 <tr>
3689 <td>1</td>
3690 <td>1</td>
3691 <td>1</td>
3692 </tr>
3693 </tbody>
3694</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3695
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3696<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3697<pre>
3698 &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]3699 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3700 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3701</pre>
3702</div>
3703<!-- _______________________________________________________________________ -->
3704<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3705
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3706<div class="doc_text">
3707
3708<h5>Syntax:</h5>
3709<pre>
3710 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3711</pre>
3712
3713<h5>Overview:</h5>
3714<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3715 two operands.</p>
3716
3717<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3718<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3719 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3720 values. Both arguments must have identical types.</p>
3721
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3722<h5>Semantics:</h5>
3723<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3724
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3725<table border="1" cellspacing="0" cellpadding="4">
3726 <tbody>
3727 <tr>
3728 <td>In0</td>
3729 <td>In1</td>
3730 <td>Out</td>
3731 </tr>
3732 <tr>
3733 <td>0</td>
3734 <td>0</td>
3735 <td>0</td>
3736 </tr>
3737 <tr>
3738 <td>0</td>
3739 <td>1</td>
3740 <td>1</td>
3741 </tr>
3742 <tr>
3743 <td>1</td>
3744 <td>0</td>
3745 <td>1</td>
3746 </tr>
3747 <tr>
3748 <td>1</td>
3749 <td>1</td>
3750 <td>1</td>
3751 </tr>
3752 </tbody>
3753</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3754
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3755<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3756<pre>
3757 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3758 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3759 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3760</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3761
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3762</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3763
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3764<!-- _______________________________________________________________________ -->
3765<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3766Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3767
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3768<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3769
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3770<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3771<pre>
3772 &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]3773</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3774
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3775<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3776<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3777 its two operands. The <tt>xor</tt> is used to implement the "one's
3778 complement" operation, which is the "~" operator in C.</p>
3779
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3780<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3781<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3782 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3783 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3784
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3785<h5>Semantics:</h5>
3786<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3787
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3788<table border="1" cellspacing="0" cellpadding="4">
3789 <tbody>
3790 <tr>
3791 <td>In0</td>
3792 <td>In1</td>
3793 <td>Out</td>
3794 </tr>
3795 <tr>
3796 <td>0</td>
3797 <td>0</td>
3798 <td>0</td>
3799 </tr>
3800 <tr>
3801 <td>0</td>
3802 <td>1</td>
3803 <td>1</td>
3804 </tr>
3805 <tr>
3806 <td>1</td>
3807 <td>0</td>
3808 <td>1</td>
3809 </tr>
3810 <tr>
3811 <td>1</td>
3812 <td>1</td>
3813 <td>0</td>
3814 </tr>
3815 </tbody>
3816</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3817
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3818<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3819<pre>
3820 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3821 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3822 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3823 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3824</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3825
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3826</div>
3827
3828<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3829<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3830 <a name="vectorops">Vector Operations</a>
3831</div>
3832
3833<div class="doc_text">
3834
3835<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3836 target-independent manner. These instructions cover the element-access and
3837 vector-specific operations needed to process vectors effectively. While LLVM
3838 does directly support these vector operations, many sophisticated algorithms
3839 will want to use target-specific intrinsics to take full advantage of a
3840 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3841
3842</div>
3843
3844<!-- _______________________________________________________________________ -->
3845<div class="doc_subsubsection">
3846 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3847</div>
3848
3849<div class="doc_text">
3850
3851<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3852<pre>
3853 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3854</pre>
3855
3856<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3857<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3858 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3859
3860
3861<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3862<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3863 of <a href="#t_vector">vector</a> type. The second operand is an index
3864 indicating the position from which to extract the element. The index may be
3865 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3866
3867<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3868<p>The result is a scalar of the same type as the element type of
3869 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3870 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3871 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3872
3873<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3874<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3875 &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]3876</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3877
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3878</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3879
3880<!-- _______________________________________________________________________ -->
3881<div class="doc_subsubsection">
3882 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3883</div>
3884
3885<div class="doc_text">
3886
3887<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3888<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3889 &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]3890</pre>
3891
3892<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3893<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3894 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3895
3896<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3897<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3898 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3899 whose type must equal the element type of the first operand. The third
3900 operand is an index indicating the position at which to insert the value.
3901 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3902
3903<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3904<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3905 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3906 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3907 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3908
3909<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3910<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3911 &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]3912</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3913
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3914</div>
3915
3916<!-- _______________________________________________________________________ -->
3917<div class="doc_subsubsection">
3918 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3919</div>
3920
3921<div class="doc_text">
3922
3923<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3924<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3925 &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]3926</pre>
3927
3928<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3929<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3930 from two input vectors, returning a vector with the same element type as the
3931 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3932
3933<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3934<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3935 with types that match each other. The third argument is a shuffle mask whose
3936 element type is always 'i32'. The result of the instruction is a vector
3937 whose length is the same as the shuffle mask and whose element type is the
3938 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3939
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3940<p>The shuffle mask operand is required to be a constant vector with either
3941 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3942
3943<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3944<p>The elements of the two input vectors are numbered from left to right across
3945 both of the vectors. The shuffle mask operand specifies, for each element of
3946 the result vector, which element of the two input vectors the result element
3947 gets. The element selector may be undef (meaning "don't care") and the
3948 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3949
3950<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3951<pre>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3952 &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]3953 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3954 &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]3955 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3956 &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]3957 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3958 &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]3959 &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]3960</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3961
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3962</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3963
3964<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3965<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3966 <a name="aggregateops">Aggregate Operations</a>
3967</div>
3968
3969<div class="doc_text">
3970
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]3971<p>LLVM supports several instructions for working with
3972 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3973
3974</div>
3975
3976<!-- _______________________________________________________________________ -->
3977<div class="doc_subsubsection">
3978 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3979</div>
3980
3981<div class="doc_text">
3982
3983<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3984<pre>
3985 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3986</pre>
3987
3988<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]3989<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
3990 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3991
3992<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3993<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]3994 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
3995 <a href="#t_array">array</a> type. The operands are constant indices to
3996 specify which value to extract in a similar manner as indices in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3997 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3998
3999<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4000<p>The result is the value at the position in the aggregate specified by the
4001 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4002
4003<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4004<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4005 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4006</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4007
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4008</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4009
4010<!-- _______________________________________________________________________ -->
4011<div class="doc_subsubsection">
4012 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4013</div>
4014
4015<div class="doc_text">
4016
4017<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4018<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]4019 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, &lt;idx&gt; <i>; yields &lt;aggregate type&gt;</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4020</pre>
4021
4022<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4023<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4024 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4025
4026<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4027<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4028 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4029 <a href="#t_array">array</a> type. The second operand is a first-class
4030 value to insert. The following operands are constant indices indicating
4031 the position at which to insert the value in a similar manner as indices in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4032 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4033 value to insert must have the same type as the value identified by the
4034 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4035
4036<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4037<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4038 that of <tt>val</tt> except that the value at the position specified by the
4039 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4040
4041<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4042<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]4043 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4044 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4045</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4046
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4047</div>
4048
4049
4050<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4051<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4052 <a name="memoryops">Memory Access and Addressing Operations</a>
4053</div>
4054
4055<div class="doc_text">
4056
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4057<p>A key design point of an SSA-based representation is how it represents
4058 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]4059 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4060 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4061
4062</div>
4063
4064<!-- _______________________________________________________________________ -->
4065<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4066 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4067</div>
4068
4069<div class="doc_text">
4070
4071<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4072<pre>
4073 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
4074</pre>
4075
4076<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4077<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4078 currently executing function, to be automatically released when this function
4079 returns to its caller. The object is always allocated in the generic address
4080 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4081
4082<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4083<p>The '<tt>alloca</tt>' instruction
4084 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4085 runtime stack, returning a pointer of the appropriate type to the program.
4086 If "NumElements" is specified, it is the number of elements allocated,
4087 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4088 specified, the value result of the allocation is guaranteed to be aligned to
4089 at least that boundary. If not specified, or if zero, the target can choose
4090 to align the allocation on any convenient boundary compatible with the
4091 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4092
4093<p>'<tt>type</tt>' may be any sized type.</p>
4094
4095<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]4096<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4097 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4098 memory is automatically released when the function returns. The
4099 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4100 variables that must have an address available. When the function returns
4101 (either with the <tt><a href="#i_ret">ret</a></tt>
4102 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4103 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4104
4105<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4106<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]4107 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4108 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4109 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4110 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4111</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4112
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4113</div>
4114
4115<!-- _______________________________________________________________________ -->
4116<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4117Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4118
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4119<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4120
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4121<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4122<pre>
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4123 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4124 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4125 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4126</pre>
4127
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4128<h5>Overview:</h5>
4129<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4130
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4131<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4132<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4133 from which to load. The pointer must point to
4134 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4135 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
4136 number or order of execution of this <tt>load</tt> with other
4137 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4138 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4139
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4140<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4141 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4142 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4143 alignment for the target. It is the responsibility of the code emitter to
4144 ensure that the alignment information is correct. Overestimating the
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4145 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4146 produce less efficient code. An alignment of 1 is always safe.</p>
4147
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4148<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4149 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4150 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4151 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4152 and code generator that this load is not expected to be reused in the cache.
4153 The code generator may select special instructions to save cache bandwidth,
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4154 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4155
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4156<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4157<p>The location of memory pointed to is loaded. If the value being loaded is of
4158 scalar type then the number of bytes read does not exceed the minimum number
4159 of bytes needed to hold all bits of the type. For example, loading an
4160 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4161 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4162 is undefined if the value was not originally written using a store of the
4163 same type.</p>
4164
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4165<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4166<pre>
4167 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4168 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4169 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
4170</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4171
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4172</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4173
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4174<!-- _______________________________________________________________________ -->
4175<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4176Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4177
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4178<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4179
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4180<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4181<pre>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4182 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4183 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4184</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4185
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4186<h5>Overview:</h5>
4187<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4188
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4189<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4190<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4191 and an address at which to store it. The type of the
4192 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4193 the <a href="#t_firstclass">first class</a> type of the
4194 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4195 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4196 or order of execution of this <tt>store</tt> with other
4197 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4198 instructions.</p>
4199
4200<p>The optional constant "align" argument specifies the alignment of the
4201 operation (that is, the alignment of the memory address). A value of 0 or an
4202 omitted "align" argument means that the operation has the preferential
4203 alignment for the target. It is the responsibility of the code emitter to
4204 ensure that the alignment information is correct. Overestimating the
4205 alignment results in an undefined behavior. Underestimating the alignment may
4206 produce less efficient code. An alignment of 1 is always safe.</p>
4207
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4208<p>The optional !nontemporal metadata must reference a single metatadata
4209 name <index> corresponding to a metadata node with one i32 entry of
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4210 value 1. The existence of the !nontemporal metatadata on the
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4211 instruction tells the optimizer and code generator that this load is
4212 not expected to be reused in the cache. The code generator may
4213 select special instructions to save cache bandwidth, such as the
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4214 MOVNT instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4215
4216
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4217<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4218<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4219 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4220 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4221 does not exceed the minimum number of bytes needed to hold all bits of the
4222 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4223 writing a value of a type like <tt>i20</tt> with a size that is not an
4224 integral number of bytes, it is unspecified what happens to the extra bits
4225 that do not belong to the type, but they will typically be overwritten.</p>
4226
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4227<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4228<pre>
4229 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4230 store i32 3, i32* %ptr <i>; yields {void}</i>
4231 %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]4232</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4233
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4234</div>
4235
4236<!-- _______________________________________________________________________ -->
4237<div class="doc_subsubsection">
4238 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4239</div>
4240
4241<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4242
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4243<h5>Syntax:</h5>
4244<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4245 &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]4246 &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]4247</pre>
4248
4249<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4250<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4251 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4252 It performs address calculation only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4253
4254<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4255<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4256 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4257 elements of the aggregate object are indexed. The interpretation of each
4258 index is dependent on the type being indexed into. The first index always
4259 indexes the pointer value given as the first argument, the second index
4260 indexes a value of the type pointed to (not necessarily the value directly
4261 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4262 indexed into must be a pointer value, subsequent types can be arrays,
4263 vectors, structs and unions. Note that subsequent types being indexed into
4264 can never be pointers, since that would require loading the pointer before
4265 continuing calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4266
4267<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4268 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4269 integer <b>constants</b> are allowed. When indexing into an array, pointer
4270 or vector, integers of any width are allowed, and they are not required to be
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4271 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4272
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4273<p>For example, let's consider a C code fragment and how it gets compiled to
4274 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4275
4276<div class="doc_code">
4277<pre>
4278struct RT {
4279 char A;
4280 int B[10][20];
4281 char C;
4282};
4283struct ST {
4284 int X;
4285 double Y;
4286 struct RT Z;
4287};
4288
4289int *foo(struct ST *s) {
4290 return &amp;s[1].Z.B[5][13];
4291}
4292</pre>
4293</div>
4294
4295<p>The LLVM code generated by the GCC frontend is:</p>
4296
4297<div class="doc_code">
4298<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4299%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4300%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4301
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4302define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4303entry:
4304 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4305 ret i32* %reg
4306}
4307</pre>
4308</div>
4309
4310<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4311<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]4312 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4313 }</tt>' type, a structure. The second index indexes into the third element
4314 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4315 i8 }</tt>' type, another structure. The third index indexes into the second
4316 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4317 array. The two dimensions of the array are subscripted into, yielding an
4318 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4319 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4320
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4321<p>Note that it is perfectly legal to index partially through a structure,
4322 returning a pointer to an inner element. Because of this, the LLVM code for
4323 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4324
4325<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4326 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4327 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4328 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4329 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4330 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4331 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4332 ret i32* %t5
4333 }
4334</pre>
4335
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4336<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4337 <tt>getelementptr</tt> is undefined if the base pointer is not an
4338 <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]4339 that would be formed by successive addition of the offsets implied by the
4340 indices to the base address with infinitely precise arithmetic are not an
4341 <i>in bounds</i> address of that allocated object.
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4342 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4343 that point into the object, plus the address one byte past the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4344
4345<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4346 the base address with silently-wrapping two's complement arithmetic, and
4347 the result value of the <tt>getelementptr</tt> may be outside the object
4348 pointed to by the base pointer. The result value may not necessarily be
4349 used to access memory though, even if it happens to point into allocated
4350 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4351 section for more information.</p>
4352
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4353<p>The getelementptr instruction is often confusing. For some more insight into
4354 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4355
4356<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4357<pre>
4358 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4359 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4360 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4361 %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]4362 <i>; yields i8*:eptr</i>
4363 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4364 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4365 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4366</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4367
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4368</div>
4369
4370<!-- ======================================================================= -->
4371<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4372</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4373
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4374<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4375
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4376<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4377 which all take a single operand and a type. They perform various bit
4378 conversions on the operand.</p>
4379
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4380</div>
4381
4382<!-- _______________________________________________________________________ -->
4383<div class="doc_subsubsection">
4384 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4385</div>
4386<div class="doc_text">
4387
4388<h5>Syntax:</h5>
4389<pre>
4390 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4391</pre>
4392
4393<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4394<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4395 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4396
4397<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4398<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4399 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4400 size and type of the result, which must be
4401 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4402 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4403 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4404
4405<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4406<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4407 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4408 source size must be larger than the destination size, <tt>trunc</tt> cannot
4409 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4410
4411<h5>Example:</h5>
4412<pre>
4413 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4414 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4415 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4416</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4417
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4418</div>
4419
4420<!-- _______________________________________________________________________ -->
4421<div class="doc_subsubsection">
4422 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4423</div>
4424<div class="doc_text">
4425
4426<h5>Syntax:</h5>
4427<pre>
4428 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4429</pre>
4430
4431<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4432<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4433 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4434
4435
4436<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4437<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]4438 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4439 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4440 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4441 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4442
4443<h5>Semantics:</h5>
4444<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]4445 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4446
4447<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4448
4449<h5>Example:</h5>
4450<pre>
4451 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4452 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4453</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4454
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4455</div>
4456
4457<!-- _______________________________________________________________________ -->
4458<div class="doc_subsubsection">
4459 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4460</div>
4461<div class="doc_text">
4462
4463<h5>Syntax:</h5>
4464<pre>
4465 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4466</pre>
4467
4468<h5>Overview:</h5>
4469<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4470
4471<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4472<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4473 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4474 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4475 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4476 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4477
4478<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4479<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4480 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4481 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4482
4483<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4484
4485<h5>Example:</h5>
4486<pre>
4487 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4488 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4489</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4490
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4491</div>
4492
4493<!-- _______________________________________________________________________ -->
4494<div class="doc_subsubsection">
4495 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4496</div>
4497
4498<div class="doc_text">
4499
4500<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4501<pre>
4502 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4503</pre>
4504
4505<h5>Overview:</h5>
4506<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4507 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4508
4509<h5>Arguments:</h5>
4510<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4511 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4512 to cast it to. The size of <tt>value</tt> must be larger than the size of
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4513 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4514 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4515
4516<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4517<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4518 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4519 <a href="#t_floating">floating point</a> type. If the value cannot fit
4520 within the destination type, <tt>ty2</tt>, then the results are
4521 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4522
4523<h5>Example:</h5>
4524<pre>
4525 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4526 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4527</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4528
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4529</div>
4530
4531<!-- _______________________________________________________________________ -->
4532<div class="doc_subsubsection">
4533 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4534</div>
4535<div class="doc_text">
4536
4537<h5>Syntax:</h5>
4538<pre>
4539 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4540</pre>
4541
4542<h5>Overview:</h5>
4543<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]4544 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4545
4546<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4547<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4548 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4549 a <a href="#t_floating">floating point</a> type to cast it to. The source
4550 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4551
4552<h5>Semantics:</h5>
4553<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4554 <a href="#t_floating">floating point</a> type to a larger
4555 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4556 used to make a <i>no-op cast</i> because it always changes bits. Use
4557 <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]4558
4559<h5>Example:</h5>
4560<pre>
4561 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4562 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4563</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4564
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4565</div>
4566
4567<!-- _______________________________________________________________________ -->
4568<div class="doc_subsubsection">
4569 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4570</div>
4571<div class="doc_text">
4572
4573<h5>Syntax:</h5>
4574<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4575 &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]4576</pre>
4577
4578<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4579<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4580 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4581
4582<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4583<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4584 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4585 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4586 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4587 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4588
4589<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4590<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4591 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4592 towards zero) unsigned integer value. If the value cannot fit
4593 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4594
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4595<h5>Example:</h5>
4596<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4597 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4598 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4599 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4600</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4601
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4602</div>
4603
4604<!-- _______________________________________________________________________ -->
4605<div class="doc_subsubsection">
4606 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4607</div>
4608<div class="doc_text">
4609
4610<h5>Syntax:</h5>
4611<pre>
4612 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4613</pre>
4614
4615<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4616<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4617 <a href="#t_floating">floating point</a> <tt>value</tt> to
4618 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4619
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4620<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4621<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4622 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4623 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4624 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4625 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4626
4627<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4628<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4629 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4630 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4631 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4632
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4633<h5>Example:</h5>
4634<pre>
4635 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4636 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4637 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4638</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4640</div>
4641
4642<!-- _______________________________________________________________________ -->
4643<div class="doc_subsubsection">
4644 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4645</div>
4646<div class="doc_text">
4647
4648<h5>Syntax:</h5>
4649<pre>
4650 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4651</pre>
4652
4653<h5>Overview:</h5>
4654<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4655 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4656
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4657<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4658<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]4659 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4660 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4661 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4662 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4663
4664<h5>Semantics:</h5>
4665<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4666 integer quantity and converts it to the corresponding floating point
4667 value. If the value cannot fit in the floating point value, the results are
4668 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4669
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4670<h5>Example:</h5>
4671<pre>
4672 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4673 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4674</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4675
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4676</div>
4677
4678<!-- _______________________________________________________________________ -->
4679<div class="doc_subsubsection">
4680 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4681</div>
4682<div class="doc_text">
4683
4684<h5>Syntax:</h5>
4685<pre>
4686 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4687</pre>
4688
4689<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4690<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4691 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4692
4693<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4694<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]4695 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4696 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4697 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4698 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4699
4700<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4701<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4702 quantity and converts it to the corresponding floating point value. If the
4703 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4704
4705<h5>Example:</h5>
4706<pre>
4707 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4708 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4709</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4710
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4711</div>
4712
4713<!-- _______________________________________________________________________ -->
4714<div class="doc_subsubsection">
4715 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4716</div>
4717<div class="doc_text">
4718
4719<h5>Syntax:</h5>
4720<pre>
4721 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4722</pre>
4723
4724<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4725<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4726 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4727
4728<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4729<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4730 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4731 <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]4732
4733<h5>Semantics:</h5>
4734<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4735 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4736 truncating or zero extending that value to the size of the integer type. If
4737 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4738 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4739 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4740 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4741
4742<h5>Example:</h5>
4743<pre>
4744 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4745 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4746</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4747
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4748</div>
4749
4750<!-- _______________________________________________________________________ -->
4751<div class="doc_subsubsection">
4752 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4753</div>
4754<div class="doc_text">
4755
4756<h5>Syntax:</h5>
4757<pre>
4758 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4759</pre>
4760
4761<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4762<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4763 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4764
4765<h5>Arguments:</h5>
4766<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4767 value to cast, and a type to cast it to, which must be a
4768 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4769
4770<h5>Semantics:</h5>
4771<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4772 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4773 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4774 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4775 than the size of a pointer then a zero extension is done. If they are the
4776 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4777
4778<h5>Example:</h5>
4779<pre>
4780 %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]4781 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4782 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4783</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4784
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4785</div>
4786
4787<!-- _______________________________________________________________________ -->
4788<div class="doc_subsubsection">
4789 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4790</div>
4791<div class="doc_text">
4792
4793<h5>Syntax:</h5>
4794<pre>
4795 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4796</pre>
4797
4798<h5>Overview:</h5>
4799<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4800 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4801
4802<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4803<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4804 non-aggregate first class value, and a type to cast it to, which must also be
4805 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4806 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4807 identical. If the source type is a pointer, the destination type must also be
4808 a pointer. This instruction supports bitwise conversion of vectors to
4809 integers and to vectors of other types (as long as they have the same
4810 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4811
4812<h5>Semantics:</h5>
4813<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4814 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4815 this conversion. The conversion is done as if the <tt>value</tt> had been
4816 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4817 be converted to other pointer types with this instruction. To convert
4818 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4819 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4820
4821<h5>Example:</h5>
4822<pre>
4823 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4824 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4825 %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]4826</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4827
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4828</div>
4829
4830<!-- ======================================================================= -->
4831<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4832
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4833<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4834
4835<p>The instructions in this category are the "miscellaneous" instructions, which
4836 defy better classification.</p>
4837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4838</div>
4839
4840<!-- _______________________________________________________________________ -->
4841<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4842</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4843
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4844<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4845
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4846<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4847<pre>
4848 &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]4849</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4850
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4851<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4852<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4853 boolean values based on comparison of its two integer, integer vector, or
4854 pointer operands.</p>
4855
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4856<h5>Arguments:</h5>
4857<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4858 the condition code indicating the kind of comparison to perform. It is not a
4859 value, just a keyword. The possible condition code are:</p>
4860
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4861<ol>
4862 <li><tt>eq</tt>: equal</li>
4863 <li><tt>ne</tt>: not equal </li>
4864 <li><tt>ugt</tt>: unsigned greater than</li>
4865 <li><tt>uge</tt>: unsigned greater or equal</li>
4866 <li><tt>ult</tt>: unsigned less than</li>
4867 <li><tt>ule</tt>: unsigned less or equal</li>
4868 <li><tt>sgt</tt>: signed greater than</li>
4869 <li><tt>sge</tt>: signed greater or equal</li>
4870 <li><tt>slt</tt>: signed less than</li>
4871 <li><tt>sle</tt>: signed less or equal</li>
4872</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4873
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4874<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4875 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4876 typed. They must also be identical types.</p>
4877
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4878<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4879<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4880 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4881 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]4882 result, as follows:</p>
4883
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4884<ol>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4885 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4886 <tt>false</tt> otherwise. No sign interpretation is necessary or
4887 performed.</li>
4888
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4889 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4890 <tt>false</tt> otherwise. No sign interpretation is necessary or
4891 performed.</li>
4892
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4893 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4894 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4895
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4896 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4897 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4898 to <tt>op2</tt>.</li>
4899
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4900 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4901 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4902
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4903 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4904 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4905
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4906 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4907 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4908
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4909 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4910 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4911 to <tt>op2</tt>.</li>
4912
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4913 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4914 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4915
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4916 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4917 <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]4918</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4919
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4920<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4921 values are compared as if they were integers.</p>
4922
4923<p>If the operands are integer vectors, then they are compared element by
4924 element. The result is an <tt>i1</tt> vector with the same number of elements
4925 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4926
4927<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4928<pre>
4929 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4930 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4931 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4932 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4933 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4934 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4935</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4936
4937<p>Note that the code generator does not yet support vector types with
4938 the <tt>icmp</tt> instruction.</p>
4939
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4940</div>
4941
4942<!-- _______________________________________________________________________ -->
4943<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4944</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4945
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4946<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4947
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4948<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4949<pre>
4950 &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]4951</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4952
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4953<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4954<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4955 values based on comparison of its operands.</p>
4956
4957<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]4958(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4959
4960<p>If the operands are floating point vectors, then the result type is a vector
4961 of boolean with the same number of elements as the operands being
4962 compared.</p>
4963
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4964<h5>Arguments:</h5>
4965<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4966 the condition code indicating the kind of comparison to perform. It is not a
4967 value, just a keyword. The possible condition code are:</p>
4968
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4969<ol>
4970 <li><tt>false</tt>: no comparison, always returns false</li>
4971 <li><tt>oeq</tt>: ordered and equal</li>
4972 <li><tt>ogt</tt>: ordered and greater than </li>
4973 <li><tt>oge</tt>: ordered and greater than or equal</li>
4974 <li><tt>olt</tt>: ordered and less than </li>
4975 <li><tt>ole</tt>: ordered and less than or equal</li>
4976 <li><tt>one</tt>: ordered and not equal</li>
4977 <li><tt>ord</tt>: ordered (no nans)</li>
4978 <li><tt>ueq</tt>: unordered or equal</li>
4979 <li><tt>ugt</tt>: unordered or greater than </li>
4980 <li><tt>uge</tt>: unordered or greater than or equal</li>
4981 <li><tt>ult</tt>: unordered or less than </li>
4982 <li><tt>ule</tt>: unordered or less than or equal</li>
4983 <li><tt>une</tt>: unordered or not equal</li>
4984 <li><tt>uno</tt>: unordered (either nans)</li>
4985 <li><tt>true</tt>: no comparison, always returns true</li>
4986</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4987
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4988<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4989 <i>unordered</i> means that either operand may be a QNAN.</p>
4990
4991<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4992 a <a href="#t_floating">floating point</a> type or
4993 a <a href="#t_vector">vector</a> of floating point type. They must have
4994 identical types.</p>
4995
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4996<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4997<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4998 according to the condition code given as <tt>cond</tt>. If the operands are
4999 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]5000 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5001 follows:</p>
5002
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5003<ol>
5004 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5005
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5006 <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]5007 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5008
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5009 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5010 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5011
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5012 <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]5013 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5014
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5015 <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]5016 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5017
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5018 <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]5019 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5020
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5021 <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]5022 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5023
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5024 <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]5025
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5026 <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]5027 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5028
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5029 <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]5030 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5031
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5032 <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]5033 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5034
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5035 <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]5036 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5037
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5038 <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]5039 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5040
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5041 <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]5042 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5043
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5044 <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]5045
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5046 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5047</ol>
5048
5049<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5050<pre>
5051 &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]5052 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5053 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5054 &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]5055</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5056
5057<p>Note that the code generator does not yet support vector types with
5058 the <tt>fcmp</tt> instruction.</p>
5059
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5060</div>
5061
5062<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]5063<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5064 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5065</div>
5066
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5067<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5068
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5069<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5070<pre>
5071 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5072</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5073
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5074<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5075<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5076 SSA graph representing the function.</p>
5077
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5078<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5079<p>The type of the incoming values is specified with the first type field. After
5080 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5081 one pair for each predecessor basic block of the current block. Only values
5082 of <a href="#t_firstclass">first class</a> type may be used as the value
5083 arguments to the PHI node. Only labels may be used as the label
5084 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5085
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5086<p>There must be no non-phi instructions between the start of a basic block and
5087 the PHI instructions: i.e. PHI instructions must be first in a basic
5088 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5089
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5090<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5091 occur on the edge from the corresponding predecessor block to the current
5092 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5093 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]5094
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5095<h5>Semantics:</h5>
5096<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5097 specified by the pair corresponding to the predecessor basic block that
5098 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5099
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5100<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5101<pre>
5102Loop: ; Infinite loop that counts from 0 on up...
5103 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5104 %nextindvar = add i32 %indvar, 1
5105 br label %Loop
5106</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5107
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5108</div>
5109
5110<!-- _______________________________________________________________________ -->
5111<div class="doc_subsubsection">
5112 <a name="i_select">'<tt>select</tt>' Instruction</a>
5113</div>
5114
5115<div class="doc_text">
5116
5117<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5118<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]5119 &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>
5120
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5121 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5122</pre>
5123
5124<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5125<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5126 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5127
5128
5129<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5130<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5131 values indicating the condition, and two values of the
5132 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5133 vectors and the condition is a scalar, then entire vectors are selected, not
5134 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5135
5136<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5137<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5138 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5139
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5140<p>If the condition is a vector of i1, then the value arguments must be vectors
5141 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5142
5143<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5144<pre>
5145 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
5146</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5147
5148<p>Note that the code generator does not yet support conditions
5149 with vector type.</p>
5150
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5151</div>
5152
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5153<!-- _______________________________________________________________________ -->
5154<div class="doc_subsubsection">
5155 <a name="i_call">'<tt>call</tt>' Instruction</a>
5156</div>
5157
5158<div class="doc_text">
5159
5160<h5>Syntax:</h5>
5161<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]5162 &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]5163</pre>
5164
5165<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5166<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
5167
5168<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5169<p>This instruction requires several arguments:</p>
5170
5171<ol>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5172 <li>The optional "tail" marker indicates that the callee function does not
5173 access any allocas or varargs in the caller. Note that calls may be
5174 marked "tail" even if they do not occur before
5175 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5176 present, the function call is eligible for tail call optimization,
5177 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengcc7495c2010-03-08 21:05:02 +0000[diff] [blame]5178 optimized into a jump</a>. The code generator may optimize calls marked
5179 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5180 sibling call optimization</a> when the caller and callee have
5181 matching signatures, or 2) forced tail call optimization when the
5182 following extra requirements are met:
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5183 <ul>
5184 <li>Caller and callee both have the calling
5185 convention <tt>fastcc</tt>.</li>
5186 <li>The call is in tail position (ret immediately follows call and ret
5187 uses value of call or is void).</li>
5188 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman1be84f02010-03-02 01:08:11 +0000[diff] [blame]5189 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5190 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5191 constraints are met.</a></li>
5192 </ul>
5193 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5194
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5195 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5196 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5197 defaults to using C calling conventions. The calling convention of the
5198 call must match the calling convention of the target function, or else the
5199 behavior is undefined.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5200
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5201 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5202 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5203 '<tt>inreg</tt>' attributes are valid here.</li>
5204
5205 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5206 type of the return value. Functions that return no value are marked
5207 <tt><a href="#t_void">void</a></tt>.</li>
5208
5209 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5210 being invoked. The argument types must match the types implied by this
5211 signature. This type can be omitted if the function is not varargs and if
5212 the function type does not return a pointer to a function.</li>
5213
5214 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5215 be invoked. In most cases, this is a direct function invocation, but
5216 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5217 to function value.</li>
5218
5219 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]5220 signature argument types and parameter attributes. All arguments must be
5221 of <a href="#t_firstclass">first class</a> type. If the function
5222 signature indicates the function accepts a variable number of arguments,
5223 the extra arguments can be specified.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5224
5225 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5226 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5227 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5228</ol>
5229
5230<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5231<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5232 a specified function, with its incoming arguments bound to the specified
5233 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5234 function, control flow continues with the instruction after the function
5235 call, and the return value of the function is bound to the result
5236 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5237
5238<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5239<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5240 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5241 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5242 %X = tail call i32 @foo() <i>; yields i32</i>
5243 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5244 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5245
5246 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5247 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5248 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5249 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5250 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5251 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5252</pre>
5253
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5254<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5255standard C99 library as being the C99 library functions, and may perform
5256optimizations or generate code for them under that assumption. This is
5257something we'd like to change in the future to provide better support for
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5258freestanding environments and non-C-based languages.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5259
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5260</div>
5261
5262<!-- _______________________________________________________________________ -->
5263<div class="doc_subsubsection">
5264 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5265</div>
5266
5267<div class="doc_text">
5268
5269<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5270<pre>
5271 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5272</pre>
5273
5274<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5275<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5276 the "variable argument" area of a function call. It is used to implement the
5277 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5278
5279<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5280<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5281 argument. It returns a value of the specified argument type and increments
5282 the <tt>va_list</tt> to point to the next argument. The actual type
5283 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5284
5285<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5286<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5287 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5288 to the next argument. For more information, see the variable argument
5289 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5290
5291<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]5292 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5293 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5294
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5295<p><tt>va_arg</tt> is an LLVM instruction instead of
5296 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5297 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5298
5299<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5300<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5301
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5302<p>Note that the code generator does not yet fully support va_arg on many
5303 targets. Also, it does not currently support va_arg with aggregate types on
5304 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5305
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5306</div>
5307
5308<!-- *********************************************************************** -->
5309<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5310<!-- *********************************************************************** -->
5311
5312<div class="doc_text">
5313
5314<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5315 well known names and semantics and are required to follow certain
5316 restrictions. Overall, these intrinsics represent an extension mechanism for
5317 the LLVM language that does not require changing all of the transformations
5318 in LLVM when adding to the language (or the bitcode reader/writer, the
5319 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5320
5321<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5322 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5323 begin with this prefix. Intrinsic functions must always be external
5324 functions: you cannot define the body of intrinsic functions. Intrinsic
5325 functions may only be used in call or invoke instructions: it is illegal to
5326 take the address of an intrinsic function. Additionally, because intrinsic
5327 functions are part of the LLVM language, it is required if any are added that
5328 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5329
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5330<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5331 family of functions that perform the same operation but on different data
5332 types. Because LLVM can represent over 8 million different integer types,
5333 overloading is used commonly to allow an intrinsic function to operate on any
5334 integer type. One or more of the argument types or the result type can be
5335 overloaded to accept any integer type. Argument types may also be defined as
5336 exactly matching a previous argument's type or the result type. This allows
5337 an intrinsic function which accepts multiple arguments, but needs all of them
5338 to be of the same type, to only be overloaded with respect to a single
5339 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5340
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5341<p>Overloaded intrinsics will have the names of its overloaded argument types
5342 encoded into its function name, each preceded by a period. Only those types
5343 which are overloaded result in a name suffix. Arguments whose type is matched
5344 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5345 can take an integer of any width and returns an integer of exactly the same
5346 integer width. This leads to a family of functions such as
5347 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5348 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5349 suffix is required. Because the argument's type is matched against the return
5350 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5351
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5352<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5353 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5354
5355</div>
5356
5357<!-- ======================================================================= -->
5358<div class="doc_subsection">
5359 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5360</div>
5361
5362<div class="doc_text">
5363
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5364<p>Variable argument support is defined in LLVM with
5365 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5366 intrinsic functions. These functions are related to the similarly named
5367 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5368
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5369<p>All of these functions operate on arguments that use a target-specific value
5370 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5371 not define what this type is, so all transformations should be prepared to
5372 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5373
5374<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]5375 instruction and the variable argument handling intrinsic functions are
5376 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5377
5378<div class="doc_code">
5379<pre>
5380define i32 @test(i32 %X, ...) {
5381 ; Initialize variable argument processing
5382 %ap = alloca i8*
5383 %ap2 = bitcast i8** %ap to i8*
5384 call void @llvm.va_start(i8* %ap2)
5385
5386 ; Read a single integer argument
5387 %tmp = va_arg i8** %ap, i32
5388
5389 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5390 %aq = alloca i8*
5391 %aq2 = bitcast i8** %aq to i8*
5392 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5393 call void @llvm.va_end(i8* %aq2)
5394
5395 ; Stop processing of arguments.
5396 call void @llvm.va_end(i8* %ap2)
5397 ret i32 %tmp
5398}
5399
5400declare void @llvm.va_start(i8*)
5401declare void @llvm.va_copy(i8*, i8*)
5402declare void @llvm.va_end(i8*)
5403</pre>
5404</div>
5405
5406</div>
5407
5408<!-- _______________________________________________________________________ -->
5409<div class="doc_subsubsection">
5410 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5411</div>
5412
5413
5414<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5415
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5416<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5417<pre>
5418 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5419</pre>
5420
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5421<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5422<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5423 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]5424
5425<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5426<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]5427
5428<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5429<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]5430 macro available in C. In a target-dependent way, it initializes
5431 the <tt>va_list</tt> element to which the argument points, so that the next
5432 call to <tt>va_arg</tt> will produce the first variable argument passed to
5433 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5434 need to know the last argument of the function as the compiler can figure
5435 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5436
5437</div>
5438
5439<!-- _______________________________________________________________________ -->
5440<div class="doc_subsubsection">
5441 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5442</div>
5443
5444<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5445
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5446<h5>Syntax:</h5>
5447<pre>
5448 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5449</pre>
5450
5451<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5452<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5453 which has been initialized previously
5454 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5455 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5456
5457<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5458<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5459
5460<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5461<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]5462 macro available in C. In a target-dependent way, it destroys
5463 the <tt>va_list</tt> element to which the argument points. Calls
5464 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5465 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5466 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5467
5468</div>
5469
5470<!-- _______________________________________________________________________ -->
5471<div class="doc_subsubsection">
5472 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5473</div>
5474
5475<div class="doc_text">
5476
5477<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5478<pre>
5479 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5480</pre>
5481
5482<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5483<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5484 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5485
5486<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5487<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]5488 The second argument is a pointer to a <tt>va_list</tt> element to copy
5489 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5490
5491<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5492<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]5493 macro available in C. In a target-dependent way, it copies the
5494 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5495 element. This intrinsic is necessary because
5496 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5497 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5498
5499</div>
5500
5501<!-- ======================================================================= -->
5502<div class="doc_subsection">
5503 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5504</div>
5505
5506<div class="doc_text">
5507
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5508<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5509Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5510intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5511roots on the stack</a>, as well as garbage collector implementations that
5512require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5513barriers. Front-ends for type-safe garbage collected languages should generate
5514these intrinsics to make use of the LLVM garbage collectors. For more details,
5515see <a href="GarbageCollection.html">Accurate Garbage Collection with
5516LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5517
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5518<p>The garbage collection intrinsics only operate on objects in the generic
5519 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5520
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5521</div>
5522
5523<!-- _______________________________________________________________________ -->
5524<div class="doc_subsubsection">
5525 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5526</div>
5527
5528<div class="doc_text">
5529
5530<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5531<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5532 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5533</pre>
5534
5535<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5536<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]5537 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5538
5539<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5540<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5541 root pointer. The second pointer (which must be either a constant or a
5542 global value address) contains the meta-data to be associated with the
5543 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5544
5545<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5546<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]5547 location. At compile-time, the code generator generates information to allow
5548 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5549 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5550 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5551
5552</div>
5553
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5554<!-- _______________________________________________________________________ -->
5555<div class="doc_subsubsection">
5556 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5557</div>
5558
5559<div class="doc_text">
5560
5561<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5562<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5563 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5564</pre>
5565
5566<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5567<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5568 locations, allowing garbage collector implementations that require read
5569 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5570
5571<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5572<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]5573 allocated from the garbage collector. The first object is a pointer to the
5574 start of the referenced object, if needed by the language runtime (otherwise
5575 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5576
5577<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5578<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5579 instruction, but may be replaced with substantially more complex code by the
5580 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5581 may only be used in a function which <a href="#gc">specifies a GC
5582 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5583
5584</div>
5585
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5586<!-- _______________________________________________________________________ -->
5587<div class="doc_subsubsection">
5588 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5589</div>
5590
5591<div class="doc_text">
5592
5593<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5594<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5595 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5596</pre>
5597
5598<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5599<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5600 locations, allowing garbage collector implementations that require write
5601 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5602
5603<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5604<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]5605 object to store it to, and the third is the address of the field of Obj to
5606 store to. If the runtime does not require a pointer to the object, Obj may
5607 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5608
5609<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5610<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5611 instruction, but may be replaced with substantially more complex code by the
5612 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5613 may only be used in a function which <a href="#gc">specifies a GC
5614 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5615
5616</div>
5617
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5618<!-- ======================================================================= -->
5619<div class="doc_subsection">
5620 <a name="int_codegen">Code Generator Intrinsics</a>
5621</div>
5622
5623<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5624
5625<p>These intrinsics are provided by LLVM to expose special features that may
5626 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5627
5628</div>
5629
5630<!-- _______________________________________________________________________ -->
5631<div class="doc_subsubsection">
5632 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5633</div>
5634
5635<div class="doc_text">
5636
5637<h5>Syntax:</h5>
5638<pre>
5639 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5640</pre>
5641
5642<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5643<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5644 target-specific value indicating the return address of the current function
5645 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5646
5647<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5648<p>The argument to this intrinsic indicates which function to return the address
5649 for. Zero indicates the calling function, one indicates its caller, etc.
5650 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5651
5652<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5653<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5654 indicating the return address of the specified call frame, or zero if it
5655 cannot be identified. The value returned by this intrinsic is likely to be
5656 incorrect or 0 for arguments other than zero, so it should only be used for
5657 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5658
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5659<p>Note that calling this intrinsic does not prevent function inlining or other
5660 aggressive transformations, so the value returned may not be that of the
5661 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5663</div>
5664
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5665<!-- _______________________________________________________________________ -->
5666<div class="doc_subsubsection">
5667 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5668</div>
5669
5670<div class="doc_text">
5671
5672<h5>Syntax:</h5>
5673<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5674 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5675</pre>
5676
5677<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5678<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5679 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5680
5681<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5682<p>The argument to this intrinsic indicates which function to return the frame
5683 pointer for. Zero indicates the calling function, one indicates its caller,
5684 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5685
5686<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5687<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5688 indicating the frame address of the specified call frame, or zero if it
5689 cannot be identified. The value returned by this intrinsic is likely to be
5690 incorrect or 0 for arguments other than zero, so it should only be used for
5691 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5692
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5693<p>Note that calling this intrinsic does not prevent function inlining or other
5694 aggressive transformations, so the value returned may not be that of the
5695 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5696
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5697</div>
5698
5699<!-- _______________________________________________________________________ -->
5700<div class="doc_subsubsection">
5701 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5702</div>
5703
5704<div class="doc_text">
5705
5706<h5>Syntax:</h5>
5707<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5708 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5709</pre>
5710
5711<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5712<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5713 of the function stack, for use
5714 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5715 useful for implementing language features like scoped automatic variable
5716 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5717
5718<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5719<p>This intrinsic returns a opaque pointer value that can be passed
5720 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5721 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5722 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5723 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5724 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5725 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5726
5727</div>
5728
5729<!-- _______________________________________________________________________ -->
5730<div class="doc_subsubsection">
5731 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5732</div>
5733
5734<div class="doc_text">
5735
5736<h5>Syntax:</h5>
5737<pre>
5738 declare void @llvm.stackrestore(i8 * %ptr)
5739</pre>
5740
5741<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5742<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5743 the function stack to the state it was in when the
5744 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5745 executed. This is useful for implementing language features like scoped
5746 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5747
5748<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5749<p>See the description
5750 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5751
5752</div>
5753
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5754<!-- _______________________________________________________________________ -->
5755<div class="doc_subsubsection">
5756 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5757</div>
5758
5759<div class="doc_text">
5760
5761<h5>Syntax:</h5>
5762<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5763 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]5764</pre>
5765
5766<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5767<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5768 insert a prefetch instruction if supported; otherwise, it is a noop.
5769 Prefetches have no effect on the behavior of the program but can change its
5770 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5771
5772<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5773<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5774 specifier determining if the fetch should be for a read (0) or write (1),
5775 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5776 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5777 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5778
5779<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5780<p>This intrinsic does not modify the behavior of the program. In particular,
5781 prefetches cannot trap and do not produce a value. On targets that support
5782 this intrinsic, the prefetch can provide hints to the processor cache for
5783 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5784
5785</div>
5786
5787<!-- _______________________________________________________________________ -->
5788<div class="doc_subsubsection">
5789 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5790</div>
5791
5792<div class="doc_text">
5793
5794<h5>Syntax:</h5>
5795<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5796 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5797</pre>
5798
5799<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5800<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5801 Counter (PC) in a region of code to simulators and other tools. The method
5802 is target specific, but it is expected that the marker will use exported
5803 symbols to transmit the PC of the marker. The marker makes no guarantees
5804 that it will remain with any specific instruction after optimizations. It is
5805 possible that the presence of a marker will inhibit optimizations. The
5806 intended use is to be inserted after optimizations to allow correlations of
5807 simulation runs.</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><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5811
5812<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5813<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5814 not support this intrinsic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5815
5816</div>
5817
5818<!-- _______________________________________________________________________ -->
5819<div class="doc_subsubsection">
5820 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5821</div>
5822
5823<div class="doc_text">
5824
5825<h5>Syntax:</h5>
5826<pre>
5827 declare i64 @llvm.readcyclecounter( )
5828</pre>
5829
5830<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5831<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5832 counter register (or similar low latency, high accuracy clocks) on those
5833 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5834 should map to RPCC. As the backing counters overflow quickly (on the order
5835 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5836
5837<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5838<p>When directly supported, reading the cycle counter should not modify any
5839 memory. Implementations are allowed to either return a application specific
5840 value or a system wide value. On backends without support, this is lowered
5841 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5842
5843</div>
5844
5845<!-- ======================================================================= -->
5846<div class="doc_subsection">
5847 <a name="int_libc">Standard C Library Intrinsics</a>
5848</div>
5849
5850<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5851
5852<p>LLVM provides intrinsics for a few important standard C library functions.
5853 These intrinsics allow source-language front-ends to pass information about
5854 the alignment of the pointer arguments to the code generator, providing
5855 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5856
5857</div>
5858
5859<!-- _______________________________________________________________________ -->
5860<div class="doc_subsubsection">
5861 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5862</div>
5863
5864<div class="doc_text">
5865
5866<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5867<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5868 integer bit width. Not all targets support all bit widths however.</p>
5869
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5870<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5871 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5872 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5873 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5874 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5875 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5876 i32 &lt;len&gt;, i32 &lt;align&gt;)
5877 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5878 i64 &lt;len&gt;, i32 &lt;align&gt;)
5879</pre>
5880
5881<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5882<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5883 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5884
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5885<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5886 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5887
5888<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5889<p>The first argument is a pointer to the destination, the second is a pointer
5890 to the source. The third argument is an integer argument specifying the
5891 number of bytes to copy, and the fourth argument is the alignment of the
5892 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5893
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5894<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5895 then the caller guarantees that both the source and destination pointers are
5896 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5897
5898<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5899<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5900 source location to the destination location, which are not allowed to
5901 overlap. It copies "len" bytes of memory over. If the argument is known to
5902 be aligned to some boundary, this can be specified as the fourth argument,
5903 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5904
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5905</div>
5906
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5907<!-- _______________________________________________________________________ -->
5908<div class="doc_subsubsection">
5909 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5910</div>
5911
5912<div class="doc_text">
5913
5914<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5915<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]5916 width. Not all targets support all bit widths however.</p>
5917
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5918<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5919 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5920 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5921 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5922 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5923 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5924 i32 &lt;len&gt;, i32 &lt;align&gt;)
5925 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5926 i64 &lt;len&gt;, i32 &lt;align&gt;)
5927</pre>
5928
5929<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5930<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5931 source location to the destination location. It is similar to the
5932 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5933 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5934
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5935<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5936 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5937
5938<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5939<p>The first argument is a pointer to the destination, the second is a pointer
5940 to the source. The third argument is an integer argument specifying the
5941 number of bytes to copy, and the fourth argument is the alignment of the
5942 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5943
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5944<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5945 then the caller guarantees that the source and destination pointers are
5946 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5947
5948<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5949<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5950 source location to the destination location, which may overlap. It copies
5951 "len" bytes of memory over. If the argument is known to be aligned to some
5952 boundary, this can be specified as the fourth argument, otherwise it should
5953 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5954
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5955</div>
5956
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5957<!-- _______________________________________________________________________ -->
5958<div class="doc_subsubsection">
5959 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5960</div>
5961
5962<div class="doc_text">
5963
5964<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5965<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]5966 width. Not all targets support all bit widths however.</p>
5967
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5968<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5969 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5970 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5971 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5972 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5973 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5974 i32 &lt;len&gt;, i32 &lt;align&gt;)
5975 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5976 i64 &lt;len&gt;, i32 &lt;align&gt;)
5977</pre>
5978
5979<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5980<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5981 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5982
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5983<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5984 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5985
5986<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5987<p>The first argument is a pointer to the destination to fill, the second is the
5988 byte value to fill it with, the third argument is an integer argument
5989 specifying the number of bytes to fill, and the fourth argument is the known
5990 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5991
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5992<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5993 then the caller guarantees that the destination pointer is aligned to that
5994 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5995
5996<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5997<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5998 at the destination location. If the argument is known to be aligned to some
5999 boundary, this can be specified as the fourth argument, otherwise it should
6000 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6001
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6002</div>
6003
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6004<!-- _______________________________________________________________________ -->
6005<div class="doc_subsubsection">
6006 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
6007</div>
6008
6009<div class="doc_text">
6010
6011<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6012<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6013 floating point or vector of floating point type. Not all targets support all
6014 types however.</p>
6015
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6016<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]6017 declare float @llvm.sqrt.f32(float %Val)
6018 declare double @llvm.sqrt.f64(double %Val)
6019 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6020 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6021 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6022</pre>
6023
6024<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6025<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6026 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6027 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6028 behavior for negative numbers other than -0.0 (which allows for better
6029 optimization, because there is no need to worry about errno being
6030 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]6031
6032<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6033<p>The argument and return value are floating point numbers of the same
6034 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6035
6036<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6037<p>This function returns the sqrt of the specified operand if it is a
6038 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6039
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6040</div>
6041
6042<!-- _______________________________________________________________________ -->
6043<div class="doc_subsubsection">
6044 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
6045</div>
6046
6047<div class="doc_text">
6048
6049<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6050<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6051 floating point or vector of floating point type. Not all targets support all
6052 types however.</p>
6053
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6054<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]6055 declare float @llvm.powi.f32(float %Val, i32 %power)
6056 declare double @llvm.powi.f64(double %Val, i32 %power)
6057 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6058 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6059 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6060</pre>
6061
6062<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6063<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6064 specified (positive or negative) power. The order of evaluation of
6065 multiplications is not defined. When a vector of floating point type is
6066 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6067
6068<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6069<p>The second argument is an integer power, and the first is a value to raise to
6070 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6071
6072<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6073<p>This function returns the first value raised to the second power with an
6074 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6075
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6076</div>
6077
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6078<!-- _______________________________________________________________________ -->
6079<div class="doc_subsubsection">
6080 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6081</div>
6082
6083<div class="doc_text">
6084
6085<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6086<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6087 floating point or vector of floating point type. Not all targets support all
6088 types however.</p>
6089
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6090<pre>
6091 declare float @llvm.sin.f32(float %Val)
6092 declare double @llvm.sin.f64(double %Val)
6093 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6094 declare fp128 @llvm.sin.f128(fp128 %Val)
6095 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6096</pre>
6097
6098<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6099<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6100
6101<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6102<p>The argument and return value are floating point numbers of the same
6103 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6104
6105<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6106<p>This function returns the sine of the specified operand, returning the same
6107 values as the libm <tt>sin</tt> functions would, and handles error conditions
6108 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6109
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6110</div>
6111
6112<!-- _______________________________________________________________________ -->
6113<div class="doc_subsubsection">
6114 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6115</div>
6116
6117<div class="doc_text">
6118
6119<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6120<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6121 floating point or vector of floating point type. Not all targets support all
6122 types however.</p>
6123
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6124<pre>
6125 declare float @llvm.cos.f32(float %Val)
6126 declare double @llvm.cos.f64(double %Val)
6127 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6128 declare fp128 @llvm.cos.f128(fp128 %Val)
6129 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6130</pre>
6131
6132<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6133<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6134
6135<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6136<p>The argument and return value are floating point numbers of the same
6137 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6138
6139<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6140<p>This function returns the cosine of the specified operand, returning the same
6141 values as the libm <tt>cos</tt> functions would, and handles error conditions
6142 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6143
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6144</div>
6145
6146<!-- _______________________________________________________________________ -->
6147<div class="doc_subsubsection">
6148 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6149</div>
6150
6151<div class="doc_text">
6152
6153<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6154<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6155 floating point or vector of floating point type. Not all targets support all
6156 types however.</p>
6157
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6158<pre>
6159 declare float @llvm.pow.f32(float %Val, float %Power)
6160 declare double @llvm.pow.f64(double %Val, double %Power)
6161 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6162 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6163 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6164</pre>
6165
6166<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6167<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6168 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6169
6170<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6171<p>The second argument is a floating point power, and the first is a value to
6172 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6173
6174<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6175<p>This function returns the first value raised to the second power, returning
6176 the same values as the libm <tt>pow</tt> functions would, and handles error
6177 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6178
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6179</div>
6180
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6181<!-- ======================================================================= -->
6182<div class="doc_subsection">
6183 <a name="int_manip">Bit Manipulation Intrinsics</a>
6184</div>
6185
6186<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6187
6188<p>LLVM provides intrinsics for a few important bit manipulation operations.
6189 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6190
6191</div>
6192
6193<!-- _______________________________________________________________________ -->
6194<div class="doc_subsubsection">
6195 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
6196</div>
6197
6198<div class="doc_text">
6199
6200<h5>Syntax:</h5>
6201<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6202 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6203
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6204<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6205 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6206 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6207 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6208</pre>
6209
6210<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6211<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6212 values with an even number of bytes (positive multiple of 16 bits). These
6213 are useful for performing operations on data that is not in the target's
6214 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6215
6216<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6217<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6218 and low byte of the input i16 swapped. Similarly,
6219 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6220 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6221 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6222 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6223 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6224 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6225
6226</div>
6227
6228<!-- _______________________________________________________________________ -->
6229<div class="doc_subsubsection">
6230 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6231</div>
6232
6233<div class="doc_text">
6234
6235<h5>Syntax:</h5>
6236<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]6237 width. Not all targets support all bit widths however.</p>
6238
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6239<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6240 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6241 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6242 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6243 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6244 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6245</pre>
6246
6247<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6248<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6249 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6250
6251<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6252<p>The only argument is the value to be counted. The argument may be of any
6253 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6254
6255<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6256<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]6257
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6258</div>
6259
6260<!-- _______________________________________________________________________ -->
6261<div class="doc_subsubsection">
6262 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6263</div>
6264
6265<div class="doc_text">
6266
6267<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6268<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6269 integer bit width. Not all targets support all bit widths however.</p>
6270
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6271<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6272 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6273 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6274 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6275 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6276 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6277</pre>
6278
6279<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6280<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6281 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6282
6283<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6284<p>The only argument is the value to be counted. The argument may be of any
6285 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6286
6287<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6288<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6289 zeros in a variable. If the src == 0 then the result is the size in bits of
6290 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6291
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6292</div>
6293
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6294<!-- _______________________________________________________________________ -->
6295<div class="doc_subsubsection">
6296 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6297</div>
6298
6299<div class="doc_text">
6300
6301<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6302<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6303 integer bit width. Not all targets support all bit widths however.</p>
6304
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6305<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6306 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6307 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6308 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6309 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6310 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6311</pre>
6312
6313<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6314<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6315 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6316
6317<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6318<p>The only argument is the value to be counted. The argument may be of any
6319 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6320
6321<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6322<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6323 zeros in a variable. If the src == 0 then the result is the size in bits of
6324 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6325
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6326</div>
6327
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6328<!-- ======================================================================= -->
6329<div class="doc_subsection">
6330 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6331</div>
6332
6333<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6334
6335<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6336
6337</div>
6338
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6339<!-- _______________________________________________________________________ -->
6340<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6341 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6342</div>
6343
6344<div class="doc_text">
6345
6346<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6347<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]6348 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6349
6350<pre>
6351 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6352 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6353 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6354</pre>
6355
6356<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6357<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6358 a signed addition of the two arguments, and indicate whether an overflow
6359 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6360
6361<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6362<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]6363 be of integer types of any bit width, but they must have the same bit
6364 width. The second element of the result structure must be of
6365 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6366 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6367
6368<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6369<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6370 a signed addition of the two variables. They return a structure &mdash; the
6371 first element of which is the signed summation, and the second element of
6372 which is a bit specifying if the signed summation resulted in an
6373 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6374
6375<h5>Examples:</h5>
6376<pre>
6377 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6378 %sum = extractvalue {i32, i1} %res, 0
6379 %obit = extractvalue {i32, i1} %res, 1
6380 br i1 %obit, label %overflow, label %normal
6381</pre>
6382
6383</div>
6384
6385<!-- _______________________________________________________________________ -->
6386<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6387 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6388</div>
6389
6390<div class="doc_text">
6391
6392<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6393<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]6394 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6395
6396<pre>
6397 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6398 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6399 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6400</pre>
6401
6402<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6403<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6404 an unsigned addition of the two arguments, and indicate whether a carry
6405 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6406
6407<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6408<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]6409 be of integer types of any bit width, but they must have the same bit
6410 width. The second element of the result structure must be of
6411 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6412 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6413
6414<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6415<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6416 an unsigned addition of the two arguments. They return a structure &mdash;
6417 the first element of which is the sum, and the second element of which is a
6418 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6419
6420<h5>Examples:</h5>
6421<pre>
6422 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6423 %sum = extractvalue {i32, i1} %res, 0
6424 %obit = extractvalue {i32, i1} %res, 1
6425 br i1 %obit, label %carry, label %normal
6426</pre>
6427
6428</div>
6429
6430<!-- _______________________________________________________________________ -->
6431<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6432 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6433</div>
6434
6435<div class="doc_text">
6436
6437<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6438<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]6439 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6440
6441<pre>
6442 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6443 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6444 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6445</pre>
6446
6447<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6448<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6449 a signed subtraction of the two arguments, and indicate whether an overflow
6450 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6451
6452<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6453<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]6454 be of integer types of any bit width, but they must have the same bit
6455 width. The second element of the result structure must be of
6456 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6457 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6458
6459<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6460<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6461 a signed subtraction of the two arguments. They return a structure &mdash;
6462 the first element of which is the subtraction, and the second element of
6463 which is a bit specifying if the signed subtraction resulted in an
6464 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6465
6466<h5>Examples:</h5>
6467<pre>
6468 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6469 %sum = extractvalue {i32, i1} %res, 0
6470 %obit = extractvalue {i32, i1} %res, 1
6471 br i1 %obit, label %overflow, label %normal
6472</pre>
6473
6474</div>
6475
6476<!-- _______________________________________________________________________ -->
6477<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6478 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6479</div>
6480
6481<div class="doc_text">
6482
6483<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6484<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]6485 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6486
6487<pre>
6488 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6489 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6490 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6491</pre>
6492
6493<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6494<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6495 an unsigned subtraction of the two arguments, and indicate whether an
6496 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6497
6498<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6499<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]6500 be of integer types of any bit width, but they must have the same bit
6501 width. The second element of the result structure must be of
6502 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6503 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6504
6505<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6506<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6507 an unsigned subtraction of the two arguments. They return a structure &mdash;
6508 the first element of which is the subtraction, and the second element of
6509 which is a bit specifying if the unsigned subtraction resulted in an
6510 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6511
6512<h5>Examples:</h5>
6513<pre>
6514 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6515 %sum = extractvalue {i32, i1} %res, 0
6516 %obit = extractvalue {i32, i1} %res, 1
6517 br i1 %obit, label %overflow, label %normal
6518</pre>
6519
6520</div>
6521
6522<!-- _______________________________________________________________________ -->
6523<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6524 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6525</div>
6526
6527<div class="doc_text">
6528
6529<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6530<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]6531 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6532
6533<pre>
6534 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6535 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6536 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6537</pre>
6538
6539<h5>Overview:</h5>
6540
6541<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6542 a signed multiplication of the two arguments, and indicate whether an
6543 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6544
6545<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6546<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]6547 be of integer types of any bit width, but they must have the same bit
6548 width. The second element of the result structure must be of
6549 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6550 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6551
6552<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6553<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6554 a signed multiplication of the two arguments. They return a structure &mdash;
6555 the first element of which is the multiplication, and the second element of
6556 which is a bit specifying if the signed multiplication resulted in an
6557 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6558
6559<h5>Examples:</h5>
6560<pre>
6561 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6562 %sum = extractvalue {i32, i1} %res, 0
6563 %obit = extractvalue {i32, i1} %res, 1
6564 br i1 %obit, label %overflow, label %normal
6565</pre>
6566
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6567</div>
6568
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6569<!-- _______________________________________________________________________ -->
6570<div class="doc_subsubsection">
6571 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6572</div>
6573
6574<div class="doc_text">
6575
6576<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6577<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]6578 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6579
6580<pre>
6581 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6582 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6583 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6584</pre>
6585
6586<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6587<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6588 a unsigned multiplication of the two arguments, and indicate whether an
6589 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6590
6591<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6592<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]6593 be of integer types of any bit width, but they must have the same bit
6594 width. The second element of the result structure must be of
6595 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6596 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6597
6598<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6599<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6600 an unsigned multiplication of the two arguments. They return a structure
6601 &mdash; the first element of which is the multiplication, and the second
6602 element of which is a bit specifying if the unsigned multiplication resulted
6603 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6604
6605<h5>Examples:</h5>
6606<pre>
6607 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6608 %sum = extractvalue {i32, i1} %res, 0
6609 %obit = extractvalue {i32, i1} %res, 1
6610 br i1 %obit, label %overflow, label %normal
6611</pre>
6612
6613</div>
6614
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6615<!-- ======================================================================= -->
6616<div class="doc_subsection">
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame^]6617 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6618</div>
6619
6620<div class="doc_text">
6621
6622<p>Half precision floating point is storage-only format. That is why the values
6623 in such format should be promoted to single precision format before any
6624 operations. LLVM provides intrinsics for conversions to single precision and
6625 back.</p>
6626
6627</div>
6628
6629<!-- _______________________________________________________________________ -->
6630<div class="doc_subsubsection">
6631 <a name="int_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
6632</div>
6633
6634<div class="doc_text">
6635
6636<h5>Syntax:</h5>
6637<pre>
6638 declare i16 @llvm.convert.to.fp16(f32 %a)
6639</pre>
6640
6641<h5>Overview:</h5>
6642<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6643 a conversion from single precision floating point format to half precision
6644 floating point format.</p>
6645
6646<h5>Arguments:</h5>
6647<p>The intrinsic function contains single argument - the value to be
6648 converted.</p>
6649
6650<h5>Semantics:</h5>
6651<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6652 a conversion from single precision floating point format to half precision
6653 floating point format. Since the format is storage only the return value is
6654 just an <tt>i16</tt> which contains the converted number.</p>
6655
6656<h5>Examples:</h5>
6657<pre>
6658 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6659 store i16 %res, i16* @x, align 2
6660</pre>
6661
6662</div>
6663
6664<!-- _______________________________________________________________________ -->
6665<div class="doc_subsubsection">
6666 <a name="int_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
6667</div>
6668
6669<div class="doc_text">
6670
6671<h5>Syntax:</h5>
6672<pre>
6673 declare f32 @llvm.convert.from.fp16(i16 %a)
6674</pre>
6675
6676<h5>Overview:</h5>
6677<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6678 a conversion from half precision floating point format to single precision
6679 floating point format.</p>
6680
6681<h5>Arguments:</h5>
6682<p>The intrinsic function contains single argument - the value to be
6683 converted.</p>
6684
6685<h5>Semantics:</h5>
6686<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
6687 conversion from half single precision floating point format to signle
6688 precision floating point format. Since the format is storage only the
6689 argument is represented by an <tt>i16</tt> value.</p>
6690
6691<h5>Examples:</h5>
6692<pre>
6693 %a = load i16* @x, align 2
6694 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6695</pre>
6696
6697</div>
6698
6699<!-- ======================================================================= -->
6700<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6701 <a name="int_debugger">Debugger Intrinsics</a>
6702</div>
6703
6704<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6705
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6706<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6707 prefix), are described in
6708 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6709 Level Debugging</a> document.</p>
6710
6711</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6712
6713<!-- ======================================================================= -->
6714<div class="doc_subsection">
6715 <a name="int_eh">Exception Handling Intrinsics</a>
6716</div>
6717
6718<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6719
6720<p>The LLVM exception handling intrinsics (which all start with
6721 <tt>llvm.eh.</tt> prefix), are described in
6722 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6723 Handling</a> document.</p>
6724
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6725</div>
6726
6727<!-- ======================================================================= -->
6728<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6729 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6730</div>
6731
6732<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6733
6734<p>This intrinsic makes it possible to excise one parameter, marked with
6735 the <tt>nest</tt> attribute, from a function. The result is a callable
6736 function pointer lacking the nest parameter - the caller does not need to
6737 provide a value for it. Instead, the value to use is stored in advance in a
6738 "trampoline", a block of memory usually allocated on the stack, which also
6739 contains code to splice the nest value into the argument list. This is used
6740 to implement the GCC nested function address extension.</p>
6741
6742<p>For example, if the function is
6743 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6744 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6745 follows:</p>
6746
6747<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6748<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6749 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6750 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6751 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6752 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6753</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6754</div>
6755
6756<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6757 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6758
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6759</div>
6760
6761<!-- _______________________________________________________________________ -->
6762<div class="doc_subsubsection">
6763 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6764</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6765
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6766<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6767
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6768<h5>Syntax:</h5>
6769<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6770 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]6771</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6772
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6773<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6774<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6775 function pointer suitable for executing it.</p>
6776
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6777<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6778<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6779 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6780 sufficiently aligned block of memory; this memory is written to by the
6781 intrinsic. Note that the size and the alignment are target-specific - LLVM
6782 currently provides no portable way of determining them, so a front-end that
6783 generates this intrinsic needs to have some target-specific knowledge.
6784 The <tt>func</tt> argument must hold a function bitcast to
6785 an <tt>i8*</tt>.</p>
6786
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6787<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6788<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6789 dependent code, turning it into a function. A pointer to this function is
6790 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6791 function pointer type</a> before being called. The new function's signature
6792 is the same as that of <tt>func</tt> with any arguments marked with
6793 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6794 is allowed, and it must be of pointer type. Calling the new function is
6795 equivalent to calling <tt>func</tt> with the same argument list, but
6796 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6797 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6798 by <tt>tramp</tt> is modified, then the effect of any later call to the
6799 returned function pointer is undefined.</p>
6800
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6801</div>
6802
6803<!-- ======================================================================= -->
6804<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6805 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6806</div>
6807
6808<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6809
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6810<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6811 hardware constructs for atomic operations and memory synchronization. This
6812 provides an interface to the hardware, not an interface to the programmer. It
6813 is aimed at a low enough level to allow any programming models or APIs
6814 (Application Programming Interfaces) which need atomic behaviors to map
6815 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6816 hardware provides a "universal IR" for source languages, it also provides a
6817 starting point for developing a "universal" atomic operation and
6818 synchronization IR.</p>
6819
6820<p>These do <em>not</em> form an API such as high-level threading libraries,
6821 software transaction memory systems, atomic primitives, and intrinsic
6822 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6823 application libraries. The hardware interface provided by LLVM should allow
6824 a clean implementation of all of these APIs and parallel programming models.
6825 No one model or paradigm should be selected above others unless the hardware
6826 itself ubiquitously does so.</p>
6827
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6828</div>
6829
6830<!-- _______________________________________________________________________ -->
6831<div class="doc_subsubsection">
6832 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6833</div>
6834<div class="doc_text">
6835<h5>Syntax:</h5>
6836<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6837 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]6838</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6839
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6840<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6841<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6842 specific pairs of memory access types.</p>
6843
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6844<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6845<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6846 The first four arguments enables a specific barrier as listed below. The
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6847 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6848 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6849
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6850<ul>
6851 <li><tt>ll</tt>: load-load barrier</li>
6852 <li><tt>ls</tt>: load-store barrier</li>
6853 <li><tt>sl</tt>: store-load barrier</li>
6854 <li><tt>ss</tt>: store-store barrier</li>
6855 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6856</ul>
6857
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6858<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6859<p>This intrinsic causes the system to enforce some ordering constraints upon
6860 the loads and stores of the program. This barrier does not
6861 indicate <em>when</em> any events will occur, it only enforces
6862 an <em>order</em> in which they occur. For any of the specified pairs of load
6863 and store operations (f.ex. load-load, or store-load), all of the first
6864 operations preceding the barrier will complete before any of the second
6865 operations succeeding the barrier begin. Specifically the semantics for each
6866 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6867
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6868<ul>
6869 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6870 after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6871 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6872 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6873 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6874 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6875 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6876 load after the barrier begins.</li>
6877</ul>
6878
6879<p>These semantics are applied with a logical "and" behavior when more than one
6880 is enabled in a single memory barrier intrinsic.</p>
6881
6882<p>Backends may implement stronger barriers than those requested when they do
6883 not support as fine grained a barrier as requested. Some architectures do
6884 not need all types of barriers and on such architectures, these become
6885 noops.</p>
6886
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6887<h5>Example:</h5>
6888<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6889%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6890%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6891 store i32 4, %ptr
6892
6893%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6894 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6895 <i>; guarantee the above finishes</i>
6896 store i32 8, %ptr <i>; before this begins</i>
6897</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6898
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6899</div>
6900
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6901<!-- _______________________________________________________________________ -->
6902<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6903 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6904</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6905
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6906<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6907
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6908<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6909<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6910 any integer bit width and for different address spaces. Not all targets
6911 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6912
6913<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6914 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6915 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6916 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6917 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]6918</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6919
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6920<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6921<p>This loads a value in memory and compares it to a given value. If they are
6922 equal, it stores a new value into the memory.</p>
6923
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6924<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6925<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6926 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6927 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6928 this integer type. While any bit width integer may be used, targets may only
6929 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6930
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6931<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6932<p>This entire intrinsic must be executed atomically. It first loads the value
6933 in memory pointed to by <tt>ptr</tt> and compares it with the
6934 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6935 memory. The loaded value is yielded in all cases. This provides the
6936 equivalent of an atomic compare-and-swap operation within the SSA
6937 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6938
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6939<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6940<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6941%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6942%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6943 store i32 4, %ptr
6944
6945%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6946%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6947 <i>; yields {i32}:result1 = 4</i>
6948%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6949%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6950
6951%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6952%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6953 <i>; yields {i32}:result2 = 8</i>
6954%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6955
6956%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6957</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6958
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6959</div>
6960
6961<!-- _______________________________________________________________________ -->
6962<div class="doc_subsubsection">
6963 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6964</div>
6965<div class="doc_text">
6966<h5>Syntax:</h5>
6967
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6968<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6969 integer bit width. Not all targets support all bit widths however.</p>
6970
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6971<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6972 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6973 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6974 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6975 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]6976</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6977
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6978<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6979<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6980 the value from memory. It then stores the value in <tt>val</tt> in the memory
6981 at <tt>ptr</tt>.</p>
6982
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6983<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6984<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6985 the <tt>val</tt> argument and the result must be integers of the same bit
6986 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6987 integer type. The targets may only lower integer representations they
6988 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6989
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6990<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6991<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6992 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6993 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6994
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6995<h5>Examples:</h5>
6996<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6997%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6998%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6999 store i32 4, %ptr
7000
7001%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7002%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7003 <i>; yields {i32}:result1 = 4</i>
7004%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7005%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7006
7007%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7008%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7009 <i>; yields {i32}:result2 = 8</i>
7010
7011%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7012%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7013</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7014
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7015</div>
7016
7017<!-- _______________________________________________________________________ -->
7018<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7019 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7020
7021</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7022
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7023<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7024
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7025<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7026<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7027 any integer bit width. Not all targets support all bit widths however.</p>
7028
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7029<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7030 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7031 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7032 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7033 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]7034</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7035
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7036<h5>Overview:</h5>
7037<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7038 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7039
7040<h5>Arguments:</h5>
7041<p>The intrinsic takes two arguments, the first a pointer to an integer value
7042 and the second an integer value. The result is also an integer value. These
7043 integer types can have any bit width, but they must all have the same bit
7044 width. The targets may only lower integer representations they support.</p>
7045
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7046<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7047<p>This intrinsic does a series of operations atomically. It first loads the
7048 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7049 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]7050
7051<h5>Examples:</h5>
7052<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7053%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7054%ptr = bitcast i8* %mallocP to i32*
7055 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7056%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7057 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7058%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7059 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7060%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7061 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7062%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7063</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7064
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7065</div>
7066
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7067<!-- _______________________________________________________________________ -->
7068<div class="doc_subsubsection">
7069 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7070
7071</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7072
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7073<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7074
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7075<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7076<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7077 any integer bit width and for different address spaces. Not all targets
7078 support all bit widths however.</p>
7079
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7080<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7081 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7082 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7083 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7084 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]7085</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7086
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7087<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7088<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7089 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7090
7091<h5>Arguments:</h5>
7092<p>The intrinsic takes two arguments, the first a pointer to an integer value
7093 and the second an integer value. The result is also an integer value. These
7094 integer types can have any bit width, but they must all have the same bit
7095 width. The targets may only lower integer representations they support.</p>
7096
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7097<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7098<p>This intrinsic does a series of operations atomically. It first loads the
7099 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7100 result to <tt>ptr</tt>. It yields the original value stored
7101 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7102
7103<h5>Examples:</h5>
7104<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7105%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7106%ptr = bitcast i8* %mallocP to i32*
7107 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7108%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7109 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7110%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7111 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7112%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7113 <i>; yields {i32}:result3 = 2</i>
7114%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7115</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7116
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7117</div>
7118
7119<!-- _______________________________________________________________________ -->
7120<div class="doc_subsubsection">
7121 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7122 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7123 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7124 <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]7125</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7126
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7127<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7128
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7129<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7130<p>These are overloaded intrinsics. You can
7131 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7132 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7133 bit width and for different address spaces. Not all targets support all bit
7134 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7135
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7136<pre>
7137 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7138 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7139 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7140 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]7141</pre>
7142
7143<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7144 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7145 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7146 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7147 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]7148</pre>
7149
7150<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7151 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7152 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7153 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7154 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]7155</pre>
7156
7157<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7158 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7159 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7160 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7161 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]7162</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7163
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7164<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7165<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7166 the value stored in memory at <tt>ptr</tt>. It yields the original value
7167 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7168
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7169<h5>Arguments:</h5>
7170<p>These intrinsics take two arguments, the first a pointer to an integer value
7171 and the second an integer value. The result is also an integer value. These
7172 integer types can have any bit width, but they must all have the same bit
7173 width. The targets may only lower integer representations they support.</p>
7174
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7175<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7176<p>These intrinsics does a series of operations atomically. They first load the
7177 value stored at <tt>ptr</tt>. They then do the bitwise
7178 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7179 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7180
7181<h5>Examples:</h5>
7182<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7183%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7184%ptr = bitcast i8* %mallocP to i32*
7185 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7186%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7187 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7188%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7189 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7190%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7191 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7192%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7193 <i>; yields {i32}:result3 = FF</i>
7194%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7195</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7196
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7197</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7198
7199<!-- _______________________________________________________________________ -->
7200<div class="doc_subsubsection">
7201 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7202 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7203 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7204 <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]7205</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7206
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7207<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7208
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7209<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7210<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7211 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7212 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7213 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7214
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7215<pre>
7216 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7217 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7218 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7219 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]7220</pre>
7221
7222<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7223 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7224 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7225 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7226 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]7227</pre>
7228
7229<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7230 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7231 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7232 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7233 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]7234</pre>
7235
7236<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7237 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7238 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7239 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7240 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]7241</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7242
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7243<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7244<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7245 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7246 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7247
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7248<h5>Arguments:</h5>
7249<p>These intrinsics take two arguments, the first a pointer to an integer value
7250 and the second an integer value. The result is also an integer value. These
7251 integer types can have any bit width, but they must all have the same bit
7252 width. The targets may only lower integer representations they support.</p>
7253
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7254<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7255<p>These intrinsics does a series of operations atomically. They first load the
7256 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7257 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7258 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7259
7260<h5>Examples:</h5>
7261<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7262%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7263%ptr = bitcast i8* %mallocP to i32*
7264 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7265%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7266 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7267%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7268 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7269%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7270 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7271%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7272 <i>; yields {i32}:result3 = 8</i>
7273%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7274</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7275
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7276</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7277
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7278
7279<!-- ======================================================================= -->
7280<div class="doc_subsection">
7281 <a name="int_memorymarkers">Memory Use Markers</a>
7282</div>
7283
7284<div class="doc_text">
7285
7286<p>This class of intrinsics exists to information about the lifetime of memory
7287 objects and ranges where variables are immutable.</p>
7288
7289</div>
7290
7291<!-- _______________________________________________________________________ -->
7292<div class="doc_subsubsection">
7293 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7294</div>
7295
7296<div class="doc_text">
7297
7298<h5>Syntax:</h5>
7299<pre>
7300 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7301</pre>
7302
7303<h5>Overview:</h5>
7304<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7305 object's lifetime.</p>
7306
7307<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7308<p>The first argument is a constant integer representing the size of the
7309 object, or -1 if it is variable sized. The second argument is a pointer to
7310 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7311
7312<h5>Semantics:</h5>
7313<p>This intrinsic indicates that before this point in the code, the value of the
7314 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]7315 never be used and has an undefined value. A load from the pointer that
7316 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7317 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7318
7319</div>
7320
7321<!-- _______________________________________________________________________ -->
7322<div class="doc_subsubsection">
7323 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7324</div>
7325
7326<div class="doc_text">
7327
7328<h5>Syntax:</h5>
7329<pre>
7330 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7331</pre>
7332
7333<h5>Overview:</h5>
7334<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7335 object's lifetime.</p>
7336
7337<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7338<p>The first argument is a constant integer representing the size of the
7339 object, or -1 if it is variable sized. The second argument is a pointer to
7340 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7341
7342<h5>Semantics:</h5>
7343<p>This intrinsic indicates that after this point in the code, the value of the
7344 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7345 never be used and has an undefined value. Any stores into the memory object
7346 following this intrinsic may be removed as dead.
7347
7348</div>
7349
7350<!-- _______________________________________________________________________ -->
7351<div class="doc_subsubsection">
7352 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7353</div>
7354
7355<div class="doc_text">
7356
7357<h5>Syntax:</h5>
7358<pre>
7359 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7360</pre>
7361
7362<h5>Overview:</h5>
7363<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7364 a memory object will not change.</p>
7365
7366<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7367<p>The first argument is a constant integer representing the size of the
7368 object, or -1 if it is variable sized. The second argument is a pointer to
7369 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7370
7371<h5>Semantics:</h5>
7372<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7373 the return value, the referenced memory location is constant and
7374 unchanging.</p>
7375
7376</div>
7377
7378<!-- _______________________________________________________________________ -->
7379<div class="doc_subsubsection">
7380 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7381</div>
7382
7383<div class="doc_text">
7384
7385<h5>Syntax:</h5>
7386<pre>
7387 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7388</pre>
7389
7390<h5>Overview:</h5>
7391<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7392 a memory object are mutable.</p>
7393
7394<h5>Arguments:</h5>
7395<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7396 The second argument is a constant integer representing the size of the
7397 object, or -1 if it is variable sized and the third argument is a pointer
7398 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7399
7400<h5>Semantics:</h5>
7401<p>This intrinsic indicates that the memory is mutable again.</p>
7402
7403</div>
7404
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7405<!-- ======================================================================= -->
7406<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7407 <a name="int_general">General Intrinsics</a>
7408</div>
7409
7410<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7411
7412<p>This class of intrinsics is designed to be generic and has no specific
7413 purpose.</p>
7414
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7415</div>
7416
7417<!-- _______________________________________________________________________ -->
7418<div class="doc_subsubsection">
7419 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7420</div>
7421
7422<div class="doc_text">
7423
7424<h5>Syntax:</h5>
7425<pre>
7426 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7427</pre>
7428
7429<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7430<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7431
7432<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7433<p>The first argument is a pointer to a value, the second is a pointer to a
7434 global string, the third is a pointer to a global string which is the source
7435 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7436
7437<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7438<p>This intrinsic allows annotation of local variables with arbitrary strings.
7439 This can be useful for special purpose optimizations that want to look for
7440 these annotations. These have no other defined use, they are ignored by code
7441 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7442
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7443</div>
7444
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7445<!-- _______________________________________________________________________ -->
7446<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7447 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7448</div>
7449
7450<div class="doc_text">
7451
7452<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7453<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7454 any integer bit width.</p>
7455
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7456<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7457 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7458 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7459 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7460 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7461 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]7462</pre>
7463
7464<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7465<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7466
7467<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7468<p>The first argument is an integer value (result of some expression), the
7469 second is a pointer to a global string, the third is a pointer to a global
7470 string which is the source file name, and the last argument is the line
7471 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7472
7473<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7474<p>This intrinsic allows annotations to be put on arbitrary expressions with
7475 arbitrary strings. This can be useful for special purpose optimizations that
7476 want to look for these annotations. These have no other defined use, they
7477 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7478
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7479</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7480
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7481<!-- _______________________________________________________________________ -->
7482<div class="doc_subsubsection">
7483 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7484</div>
7485
7486<div class="doc_text">
7487
7488<h5>Syntax:</h5>
7489<pre>
7490 declare void @llvm.trap()
7491</pre>
7492
7493<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7494<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7495
7496<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7497<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7498
7499<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7500<p>This intrinsics is lowered to the target dependent trap instruction. If the
7501 target does not have a trap instruction, this intrinsic will be lowered to
7502 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7503
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7504</div>
7505
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7506<!-- _______________________________________________________________________ -->
7507<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7508 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7509</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7510
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7511<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7512
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7513<h5>Syntax:</h5>
7514<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7515 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7516</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7517
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7518<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7519<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7520 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7521 ensure that it is placed on the stack before local variables.</p>
7522
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7523<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7524<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7525 arguments. The first argument is the value loaded from the stack
7526 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7527 that has enough space to hold the value of the guard.</p>
7528
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7529<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7530<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7531 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7532 stack. This is to ensure that if a local variable on the stack is
7533 overwritten, it will destroy the value of the guard. When the function exits,
7534 the guard on the stack is checked against the original guard. If they're
7535 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7536 function.</p>
7537
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7538</div>
7539
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7540<!-- _______________________________________________________________________ -->
7541<div class="doc_subsubsection">
7542 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7543</div>
7544
7545<div class="doc_text">
7546
7547<h5>Syntax:</h5>
7548<pre>
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7549 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7550 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7551</pre>
7552
7553<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7554<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher184f44d2010-01-08 21:42:39 +0000[diff] [blame]7555 to the optimizers to discover at compile time either a) when an
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7556 operation like memcpy will either overflow a buffer that corresponds to
7557 an object, or b) to determine that a runtime check for overflow isn't
7558 necessary. An object in this context means an allocation of a
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7559 specific class, structure, array, or other object.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7560
7561<h5>Arguments:</h5>
7562<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7563 argument is a pointer to or into the <tt>object</tt>. The second argument
7564 is a boolean 0 or 1. This argument determines whether you want the
7565 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7566 1, variables are not allowed.</p>
7567
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7568<h5>Semantics:</h5>
7569<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7570 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7571 (depending on the <tt>type</tt> argument if the size cannot be determined
7572 at compile time.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7573
7574</div>
7575
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7576<!-- *********************************************************************** -->
7577<hr>
7578<address>
7579 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7580 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7581 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7582 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]7583
7584 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7585 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7586 Last modified: $Date$
7587</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7588
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7589</body>
7590</html>