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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 1fafdd816cb0a852621d1fc5af408f6659393241 / . / 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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]258 <li><a href="#int_debugger">Debugger intrinsics</a></li>
259 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]260 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]261 <ol>
262 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]263 </ol>
264 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]265 <li><a href="#int_atomics">Atomic intrinsics</a>
266 <ol>
267 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
268 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
269 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
270 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
271 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
272 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
273 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
274 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
275 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
276 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
277 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
278 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
279 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
280 </ol>
281 </li>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]282 <li><a href="#int_memorymarkers">Memory Use Markers</a>
283 <ol>
284 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
285 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
286 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
287 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
288 </ol>
289 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]290 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]291 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]292 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]293 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]294 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]295 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]296 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]297 '<tt>llvm.trap</tt>' Intrinsic</a></li>
298 <li><a href="#int_stackprotector">
299 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]300 <li><a href="#int_objectsize">
301 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]302 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]303 </li>
304 </ol>
305 </li>
306</ol>
307
308<div class="doc_author">
309 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
310 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
311</div>
312
313<!-- *********************************************************************** -->
314<div class="doc_section"> <a name="abstract">Abstract </a></div>
315<!-- *********************************************************************** -->
316
317<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]318
319<p>This document is a reference manual for the LLVM assembly language. LLVM is
320 a Static Single Assignment (SSA) based representation that provides type
321 safety, low-level operations, flexibility, and the capability of representing
322 'all' high-level languages cleanly. It is the common code representation
323 used throughout all phases of the LLVM compilation strategy.</p>
324
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]325</div>
326
327<!-- *********************************************************************** -->
328<div class="doc_section"> <a name="introduction">Introduction</a> </div>
329<!-- *********************************************************************** -->
330
331<div class="doc_text">
332
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]333<p>The LLVM code representation is designed to be used in three different forms:
334 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
335 for fast loading by a Just-In-Time compiler), and as a human readable
336 assembly language representation. This allows LLVM to provide a powerful
337 intermediate representation for efficient compiler transformations and
338 analysis, while providing a natural means to debug and visualize the
339 transformations. The three different forms of LLVM are all equivalent. This
340 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]341
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]342<p>The LLVM representation aims to be light-weight and low-level while being
343 expressive, typed, and extensible at the same time. It aims to be a
344 "universal IR" of sorts, by being at a low enough level that high-level ideas
345 may be cleanly mapped to it (similar to how microprocessors are "universal
346 IR's", allowing many source languages to be mapped to them). By providing
347 type information, LLVM can be used as the target of optimizations: for
348 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]349 variable is never accessed outside of the current function, allowing it to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]350 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]351
352</div>
353
354<!-- _______________________________________________________________________ -->
355<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
356
357<div class="doc_text">
358
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]359<p>It is important to note that this document describes 'well formed' LLVM
360 assembly language. There is a difference between what the parser accepts and
361 what is considered 'well formed'. For example, the following instruction is
362 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]363
364<div class="doc_code">
365<pre>
366%x = <a href="#i_add">add</a> i32 1, %x
367</pre>
368</div>
369
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]370<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
371 LLVM infrastructure provides a verification pass that may be used to verify
372 that an LLVM module is well formed. This pass is automatically run by the
373 parser after parsing input assembly and by the optimizer before it outputs
374 bitcode. The violations pointed out by the verifier pass indicate bugs in
375 transformation passes or input to the parser.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]376
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]377</div>
378
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]379<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]380
381<!-- *********************************************************************** -->
382<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
383<!-- *********************************************************************** -->
384
385<div class="doc_text">
386
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]387<p>LLVM identifiers come in two basic types: global and local. Global
388 identifiers (functions, global variables) begin with the <tt>'@'</tt>
389 character. Local identifiers (register names, types) begin with
390 the <tt>'%'</tt> character. Additionally, there are three different formats
391 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]392
393<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]394 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]395 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
396 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
397 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
398 other characters in their names can be surrounded with quotes. Special
399 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
400 ASCII code for the character in hexadecimal. In this way, any character
401 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]402
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]403 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]404 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]405
406 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]407 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]408</ol>
409
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]410<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]411 don't need to worry about name clashes with reserved words, and the set of
412 reserved words may be expanded in the future without penalty. Additionally,
413 unnamed identifiers allow a compiler to quickly come up with a temporary
414 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]415
416<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]417 languages. There are keywords for different opcodes
418 ('<tt><a href="#i_add">add</a></tt>',
419 '<tt><a href="#i_bitcast">bitcast</a></tt>',
420 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
421 ('<tt><a href="#t_void">void</a></tt>',
422 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
423 reserved words cannot conflict with variable names, because none of them
424 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]425
426<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]427 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]428
429<p>The easy way:</p>
430
431<div class="doc_code">
432<pre>
433%result = <a href="#i_mul">mul</a> i32 %X, 8
434</pre>
435</div>
436
437<p>After strength reduction:</p>
438
439<div class="doc_code">
440<pre>
441%result = <a href="#i_shl">shl</a> i32 %X, i8 3
442</pre>
443</div>
444
445<p>And the hard way:</p>
446
447<div class="doc_code">
448<pre>
Gabor Greifc0ea7672009-10-28 13:05:07 +0000[diff] [blame]449%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
450%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]451%result = <a href="#i_add">add</a> i32 %1, %1
452</pre>
453</div>
454
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]455<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
456 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]457
458<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]459 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]460 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]461
462 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]463 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]464
465 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]466</ol>
467
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]468<p>It also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]469 demonstrating instructions, we will follow an instruction with a comment that
470 defines the type and name of value produced. Comments are shown in italic
471 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]472
473</div>
474
475<!-- *********************************************************************** -->
476<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
477<!-- *********************************************************************** -->
478
479<!-- ======================================================================= -->
480<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
481</div>
482
483<div class="doc_text">
484
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]485<p>LLVM programs are composed of "Module"s, each of which is a translation unit
486 of the input programs. Each module consists of functions, global variables,
487 and symbol table entries. Modules may be combined together with the LLVM
488 linker, which merges function (and global variable) definitions, resolves
489 forward declarations, and merges symbol table entries. Here is an example of
490 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]491
492<div class="doc_code">
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]493<pre>
494<i>; Declare the string constant as a global constant.</i>
495<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]496
497<i>; External declaration of the puts function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]498<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]499
500<i>; Definition of main function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]501define i32 @main() { <i>; i32()* </i>
502 <i>; Convert [13 x i8]* to i8 *...</i>
503 %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]504
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]505 <i>; Call puts function to write out the string to stdout.</i>
506 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]507 <a href="#i_ret">ret</a> i32 0<br>}
508
509<i>; Named metadata</i>
510!1 = metadata !{i32 41}
511!foo = !{!1, null}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]512</pre>
513</div>
514
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]515<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]516 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]517 a <a href="#functionstructure">function definition</a> for
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]518 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
519 "<tt>foo"</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]520
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]521<p>In general, a module is made up of a list of global values, where both
522 functions and global variables are global values. Global values are
523 represented by a pointer to a memory location (in this case, a pointer to an
524 array of char, and a pointer to a function), and have one of the
525 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]526
527</div>
528
529<!-- ======================================================================= -->
530<div class="doc_subsection">
531 <a name="linkage">Linkage Types</a>
532</div>
533
534<div class="doc_text">
535
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]536<p>All Global Variables and Functions have one of the following types of
537 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]538
539<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]540 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]541 <dd>Global values with private linkage are only directly accessible by objects
542 in the current module. In particular, linking code into a module with an
543 private global value may cause the private to be renamed as necessary to
544 avoid collisions. Because the symbol is private to the module, all
545 references can be updated. This doesn't show up in any symbol table in the
546 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]547
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]549 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattner06c1ecc2009-08-24 04:32:16 +0000[diff] [blame]550 removed by the linker after evaluation. Note that (unlike private
551 symbols) linker_private symbols are subject to coalescing by the linker:
552 weak symbols get merged and redefinitions are rejected. However, unlike
553 normal strong symbols, they are removed by the linker from the final
554 linked image (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]555
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]556 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]557 <dd>Similar to private, but the value shows as a local symbol
558 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
559 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]560
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]562 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]563 into the object file corresponding to the LLVM module. They exist to
564 allow inlining and other optimizations to take place given knowledge of
565 the definition of the global, which is known to be somewhere outside the
566 module. Globals with <tt>available_externally</tt> linkage are allowed to
567 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
568 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]569
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]571 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattnerd16c5512010-01-09 19:15:14 +0000[diff] [blame]572 the same name when linkage occurs. This can be used to implement
573 some forms of inline functions, templates, or other code which must be
574 generated in each translation unit that uses it, but where the body may
575 be overridden with a more definitive definition later. Unreferenced
576 <tt>linkonce</tt> globals are allowed to be discarded. Note that
577 <tt>linkonce</tt> linkage does not actually allow the optimizer to
578 inline the body of this function into callers because it doesn't know if
579 this definition of the function is the definitive definition within the
580 program or whether it will be overridden by a stronger definition.
581 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
582 linkage.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]583
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]585 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
586 <tt>linkonce</tt> linkage, except that unreferenced globals with
587 <tt>weak</tt> linkage may not be discarded. This is used for globals that
588 are declared "weak" in C source code.</dd>
589
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]590 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]591 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
592 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
593 global scope.
594 Symbols with "<tt>common</tt>" linkage are merged in the same way as
595 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]596 <tt>common</tt> symbols may not have an explicit section,
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]597 must have a zero initializer, and may not be marked '<a
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]598 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
599 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]601
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]602 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]603 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]604 pointer to array type. When two global variables with appending linkage
605 are linked together, the two global arrays are appended together. This is
606 the LLVM, typesafe, equivalent of having the system linker append together
607 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]608
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]609 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]610 <dd>The semantics of this linkage follow the ELF object file model: the symbol
611 is weak until linked, if not linked, the symbol becomes null instead of
612 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]613
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]614 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
615 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]616 <dd>Some languages allow differing globals to be merged, such as two functions
617 with different semantics. Other languages, such as <tt>C++</tt>, ensure
618 that only equivalent globals are ever merged (the "one definition rule" -
619 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
620 and <tt>weak_odr</tt> linkage types to indicate that the global will only
621 be merged with equivalent globals. These linkage types are otherwise the
622 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]624 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]625 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]626 visible, meaning that it participates in linkage and can be used to
627 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]628</dl>
629
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]630<p>The next two types of linkage are targeted for Microsoft Windows platform
631 only. They are designed to support importing (exporting) symbols from (to)
632 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]633
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]634<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]635 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]636 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]637 or variable via a global pointer to a pointer that is set up by the DLL
638 exporting the symbol. On Microsoft Windows targets, the pointer name is
639 formed by combining <code>__imp_</code> and the function or variable
640 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]641
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]642 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]643 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]644 pointer to a pointer in a DLL, so that it can be referenced with the
645 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
646 name is formed by combining <code>__imp_</code> and the function or
647 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]648</dl>
649
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]650<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
651 another module defined a "<tt>.LC0</tt>" variable and was linked with this
652 one, one of the two would be renamed, preventing a collision. Since
653 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
654 declarations), they are accessible outside of the current module.</p>
655
656<p>It is illegal for a function <i>declaration</i> to have any linkage type
657 other than "externally visible", <tt>dllimport</tt>
658 or <tt>extern_weak</tt>.</p>
659
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]660<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]661 or <tt>weak_odr</tt> linkages.</p>
662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]663</div>
664
665<!-- ======================================================================= -->
666<div class="doc_subsection">
667 <a name="callingconv">Calling Conventions</a>
668</div>
669
670<div class="doc_text">
671
672<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]673 and <a href="#i_invoke">invokes</a> can all have an optional calling
674 convention specified for the call. The calling convention of any pair of
675 dynamic caller/callee must match, or the behavior of the program is
676 undefined. The following calling conventions are supported by LLVM, and more
677 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]678
679<dl>
680 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]681 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]682 specified) matches the target C calling conventions. This calling
683 convention supports varargs function calls and tolerates some mismatch in
684 the declared prototype and implemented declaration of the function (as
685 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]686
687 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]688 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]689 (e.g. by passing things in registers). This calling convention allows the
690 target to use whatever tricks it wants to produce fast code for the
691 target, without having to conform to an externally specified ABI
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]692 (Application Binary Interface).
693 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
694 when this convention is used.</a> This calling convention does not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]695 support varargs and requires the prototype of all callees to exactly match
696 the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]697
698 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]699 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]700 as possible under the assumption that the call is not commonly executed.
701 As such, these calls often preserve all registers so that the call does
702 not break any live ranges in the caller side. This calling convention
703 does not support varargs and requires the prototype of all callees to
704 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]705
706 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]707 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]708 target-specific calling conventions to be used. Target specific calling
709 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]710</dl>
711
712<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]713 support Pascal conventions or any other well-known target-independent
714 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]715
716</div>
717
718<!-- ======================================================================= -->
719<div class="doc_subsection">
720 <a name="visibility">Visibility Styles</a>
721</div>
722
723<div class="doc_text">
724
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]725<p>All Global Variables and Functions have one of the following visibility
726 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]727
728<dl>
729 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]730 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]731 that the declaration is visible to other modules and, in shared libraries,
732 means that the declared entity may be overridden. On Darwin, default
733 visibility means that the declaration is visible to other modules. Default
734 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]735
736 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]737 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]738 object if they are in the same shared object. Usually, hidden visibility
739 indicates that the symbol will not be placed into the dynamic symbol
740 table, so no other module (executable or shared library) can reference it
741 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]742
743 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]744 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]745 the dynamic symbol table, but that references within the defining module
746 will bind to the local symbol. That is, the symbol cannot be overridden by
747 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]748</dl>
749
750</div>
751
752<!-- ======================================================================= -->
753<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]754 <a name="namedtypes">Named Types</a>
755</div>
756
757<div class="doc_text">
758
759<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]760 it easier to read the IR and make the IR more condensed (particularly when
761 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]762
763<div class="doc_code">
764<pre>
765%mytype = type { %mytype*, i32 }
766</pre>
767</div>
768
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]769<p>You may give a name to any <a href="#typesystem">type</a> except
770 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
771 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]772
773<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]774 and that you can therefore specify multiple names for the same type. This
775 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
776 uses structural typing, the name is not part of the type. When printing out
777 LLVM IR, the printer will pick <em>one name</em> to render all types of a
778 particular shape. This means that if you have code where two different
779 source types end up having the same LLVM type, that the dumper will sometimes
780 print the "wrong" or unexpected type. This is an important design point and
781 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]782
783</div>
784
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]785<!-- ======================================================================= -->
786<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]787 <a name="globalvars">Global Variables</a>
788</div>
789
790<div class="doc_text">
791
792<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]793 instead of run-time. Global variables may optionally be initialized, may
794 have an explicit section to be placed in, and may have an optional explicit
795 alignment specified. A variable may be defined as "thread_local", which
796 means that it will not be shared by threads (each thread will have a
797 separated copy of the variable). A variable may be defined as a global
798 "constant," which indicates that the contents of the variable
799 will <b>never</b> be modified (enabling better optimization, allowing the
800 global data to be placed in the read-only section of an executable, etc).
801 Note that variables that need runtime initialization cannot be marked
802 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]803
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]804<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
805 constant, even if the final definition of the global is not. This capability
806 can be used to enable slightly better optimization of the program, but
807 requires the language definition to guarantee that optimizations based on the
808 'constantness' are valid for the translation units that do not include the
809 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]810
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]811<p>As SSA values, global variables define pointer values that are in scope
812 (i.e. they dominate) all basic blocks in the program. Global variables
813 always define a pointer to their "content" type because they describe a
814 region of memory, and all memory objects in LLVM are accessed through
815 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]816
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]817<p>A global variable may be declared to reside in a target-specific numbered
818 address space. For targets that support them, address spaces may affect how
819 optimizations are performed and/or what target instructions are used to
820 access the variable. The default address space is zero. The address space
821 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]822
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]823<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]824 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]825
826<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]827 the alignment is set to zero, the alignment of the global is set by the
828 target to whatever it feels convenient. If an explicit alignment is
829 specified, the global is forced to have at least that much alignment. All
830 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]831
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]832<p>For example, the following defines a global in a numbered address space with
833 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]834
835<div class="doc_code">
836<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]837@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]838</pre>
839</div>
840
841</div>
842
843
844<!-- ======================================================================= -->
845<div class="doc_subsection">
846 <a name="functionstructure">Functions</a>
847</div>
848
849<div class="doc_text">
850
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]851<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
852 optional <a href="#linkage">linkage type</a>, an optional
853 <a href="#visibility">visibility style</a>, an optional
854 <a href="#callingconv">calling convention</a>, a return type, an optional
855 <a href="#paramattrs">parameter attribute</a> for the return type, a function
856 name, a (possibly empty) argument list (each with optional
857 <a href="#paramattrs">parameter attributes</a>), optional
858 <a href="#fnattrs">function attributes</a>, an optional section, an optional
859 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
860 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]861
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]862<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
863 optional <a href="#linkage">linkage type</a>, an optional
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]864 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]865 <a href="#callingconv">calling convention</a>, a return type, an optional
866 <a href="#paramattrs">parameter attribute</a> for the return type, a function
867 name, a possibly empty list of arguments, an optional alignment, and an
868 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]869
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]870<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]871 (Control Flow Graph) for the function. Each basic block may optionally start
872 with a label (giving the basic block a symbol table entry), contains a list
873 of instructions, and ends with a <a href="#terminators">terminator</a>
874 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]875
876<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]877 executed on entrance to the function, and it is not allowed to have
878 predecessor basic blocks (i.e. there can not be any branches to the entry
879 block of a function). Because the block can have no predecessors, it also
880 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]881
882<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]883 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]884
885<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]886 the alignment is set to zero, the alignment of the function is set by the
887 target to whatever it feels convenient. If an explicit alignment is
888 specified, the function is forced to have at least that much alignment. All
889 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]890
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]891<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]892<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]893<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]894define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]895 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
896 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
897 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
898 [<a href="#gc">gc</a>] { ... }
899</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]900</div>
901
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]902</div>
903
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]904<!-- ======================================================================= -->
905<div class="doc_subsection">
906 <a name="aliasstructure">Aliases</a>
907</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]908
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]909<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]910
911<p>Aliases act as "second name" for the aliasee value (which can be either
912 function, global variable, another alias or bitcast of global value). Aliases
913 may have an optional <a href="#linkage">linkage type</a>, and an
914 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]915
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]916<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]917<div class="doc_code">
918<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]919@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]920</pre>
921</div>
922
923</div>
924
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]925<!-- ======================================================================= -->
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]926<div class="doc_subsection">
927 <a name="namedmetadatastructure">Named Metadata</a>
928</div>
929
930<div class="doc_text">
931
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]932<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
933 nodes</a> (but not metadata strings) and null are the only valid operands for
934 a named metadata.</p>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]935
936<h5>Syntax:</h5>
937<div class="doc_code">
938<pre>
939!1 = metadata !{metadata !"one"}
940!name = !{null, !1}
941</pre>
942</div>
943
944</div>
945
946<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]947<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]948
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]949<div class="doc_text">
950
951<p>The return type and each parameter of a function type may have a set of
952 <i>parameter attributes</i> associated with them. Parameter attributes are
953 used to communicate additional information about the result or parameters of
954 a function. Parameter attributes are considered to be part of the function,
955 not of the function type, so functions with different parameter attributes
956 can have the same function type.</p>
957
958<p>Parameter attributes are simple keywords that follow the type specified. If
959 multiple parameter attributes are needed, they are space separated. For
960 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]961
962<div class="doc_code">
963<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]964declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]965declare i32 @atoi(i8 zeroext)
966declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]967</pre>
968</div>
969
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]970<p>Note that any attributes for the function result (<tt>nounwind</tt>,
971 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]972
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]973<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]974
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]975<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]976 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]977 <dd>This indicates to the code generator that the parameter or return value
978 should be zero-extended to a 32-bit value by the caller (for a parameter)
979 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]980
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]981 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]982 <dd>This indicates to the code generator that the parameter or return value
983 should be sign-extended to a 32-bit value by the caller (for a parameter)
984 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]985
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]986 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]987 <dd>This indicates that this parameter or return value should be treated in a
988 special target-dependent fashion during while emitting code for a function
989 call or return (usually, by putting it in a register as opposed to memory,
990 though some targets use it to distinguish between two different kinds of
991 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]992
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]993 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]994 <dd>This indicates that the pointer parameter should really be passed by value
995 to the function. The attribute implies that a hidden copy of the pointee
996 is made between the caller and the callee, so the callee is unable to
997 modify the value in the callee. This attribute is only valid on LLVM
998 pointer arguments. It is generally used to pass structs and arrays by
999 value, but is also valid on pointers to scalars. The copy is considered
1000 to belong to the caller not the callee (for example,
1001 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1002 <tt>byval</tt> parameters). This is not a valid attribute for return
1003 values. The byval attribute also supports specifying an alignment with
1004 the align attribute. This has a target-specific effect on the code
1005 generator that usually indicates a desired alignment for the synthesized
1006 stack slot.</dd>
1007
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1008 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1009 <dd>This indicates that the pointer parameter specifies the address of a
1010 structure that is the return value of the function in the source program.
1011 This pointer must be guaranteed by the caller to be valid: loads and
1012 stores to the structure may be assumed by the callee to not to trap. This
1013 may only be applied to the first parameter. This is not a valid attribute
1014 for return values. </dd>
1015
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1016 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1017 <dd>This indicates that the pointer does not alias any global or any other
1018 parameter. The caller is responsible for ensuring that this is the
1019 case. On a function return value, <tt>noalias</tt> additionally indicates
1020 that the pointer does not alias any other pointers visible to the
1021 caller. For further details, please see the discussion of the NoAlias
1022 response in
1023 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1024 analysis</a>.</dd>
1025
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1026 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1027 <dd>This indicates that the callee does not make any copies of the pointer
1028 that outlive the callee itself. This is not a valid attribute for return
1029 values.</dd>
1030
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1031 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1032 <dd>This indicates that the pointer parameter can be excised using the
1033 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1034 attribute for return values.</dd>
1035</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1036
1037</div>
1038
1039<!-- ======================================================================= -->
1040<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1041 <a name="gc">Garbage Collector Names</a>
1042</div>
1043
1044<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1045
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1046<p>Each function may specify a garbage collector name, which is simply a
1047 string:</p>
1048
1049<div class="doc_code">
1050<pre>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1051define void @f() gc "name" { ... }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1052</pre>
1053</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1054
1055<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1056 collector which will cause the compiler to alter its output in order to
1057 support the named garbage collection algorithm.</p>
1058
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1059</div>
1060
1061<!-- ======================================================================= -->
1062<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1063 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1064</div>
1065
1066<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1067
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1068<p>Function attributes are set to communicate additional information about a
1069 function. Function attributes are considered to be part of the function, not
1070 of the function type, so functions with different parameter attributes can
1071 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1072
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1073<p>Function attributes are simple keywords that follow the type specified. If
1074 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1075
1076<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1077<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1078define void @f() noinline { ... }
1079define void @f() alwaysinline { ... }
1080define void @f() alwaysinline optsize { ... }
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1081define void @f() optsize { ... }
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1082</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1083</div>
1084
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1085<dl>
Charles Davisfaa8f752010-02-12 00:31:15 +0000[diff] [blame]1086 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1087 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1088 the backend should forcibly align the stack pointer. Specify the
1089 desired alignment, which must be a power of two, in parentheses.
1090
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1091 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1092 <dd>This attribute indicates that the inliner should attempt to inline this
1093 function into callers whenever possible, ignoring any active inlining size
1094 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1095
Jakob Stoklund Olesen77180732010-02-06 01:16:28 +0000[diff] [blame]1096 <dt><tt><b>inlinehint</b></tt></dt>
1097 <dd>This attribute indicates that the source code contained a hint that inlining
1098 this function is desirable (such as the "inline" keyword in C/C++). It
1099 is just a hint; it imposes no requirements on the inliner.</dd>
1100
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1101 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1102 <dd>This attribute indicates that the inliner should never inline this
1103 function in any situation. This attribute may not be used together with
1104 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1105
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1106 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1107 <dd>This attribute suggests that optimization passes and code generator passes
1108 make choices that keep the code size of this function low, and otherwise
1109 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1110
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1111 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1112 <dd>This function attribute indicates that the function never returns
1113 normally. This produces undefined behavior at runtime if the function
1114 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1115
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1116 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1117 <dd>This function attribute indicates that the function never returns with an
1118 unwind or exceptional control flow. If the function does unwind, its
1119 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1120
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1121 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1122 <dd>This attribute indicates that the function computes its result (or decides
1123 to unwind an exception) based strictly on its arguments, without
1124 dereferencing any pointer arguments or otherwise accessing any mutable
1125 state (e.g. memory, control registers, etc) visible to caller functions.
1126 It does not write through any pointer arguments
1127 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1128 changes any state visible to callers. This means that it cannot unwind
1129 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1130 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1131
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1132 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1133 <dd>This attribute indicates that the function does not write through any
1134 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1135 arguments) or otherwise modify any state (e.g. memory, control registers,
1136 etc) visible to caller functions. It may dereference pointer arguments
1137 and read state that may be set in the caller. A readonly function always
1138 returns the same value (or unwinds an exception identically) when called
1139 with the same set of arguments and global state. It cannot unwind an
1140 exception by calling the <tt>C++</tt> exception throwing methods, but may
1141 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1142
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1143 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1144 <dd>This attribute indicates that the function should emit a stack smashing
1145 protector. It is in the form of a "canary"&mdash;a random value placed on
1146 the stack before the local variables that's checked upon return from the
1147 function to see if it has been overwritten. A heuristic is used to
1148 determine if a function needs stack protectors or not.<br>
1149<br>
1150 If a function that has an <tt>ssp</tt> attribute is inlined into a
1151 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1152 function will have an <tt>ssp</tt> attribute.</dd>
1153
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1154 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1155 <dd>This attribute indicates that the function should <em>always</em> emit a
1156 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1157 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1158<br>
1159 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1160 function that doesn't have an <tt>sspreq</tt> attribute or which has
1161 an <tt>ssp</tt> attribute, then the resulting function will have
1162 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1163
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1164 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1165 <dd>This attribute indicates that the code generator should not use a red
1166 zone, even if the target-specific ABI normally permits it.</dd>
1167
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1168 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1169 <dd>This attributes disables implicit floating point instructions.</dd>
1170
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1171 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1172 <dd>This attribute disables prologue / epilogue emission for the function.
1173 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1174</dl>
1175
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1176</div>
1177
1178<!-- ======================================================================= -->
1179<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1180 <a name="moduleasm">Module-Level Inline Assembly</a>
1181</div>
1182
1183<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1184
1185<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1186 the GCC "file scope inline asm" blocks. These blocks are internally
1187 concatenated by LLVM and treated as a single unit, but may be separated in
1188 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1189
1190<div class="doc_code">
1191<pre>
1192module asm "inline asm code goes here"
1193module asm "more can go here"
1194</pre>
1195</div>
1196
1197<p>The strings can contain any character by escaping non-printable characters.
1198 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]1199 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1200
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1201<p>The inline asm code is simply printed to the machine code .s file when
1202 assembly code is generated.</p>
1203
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1204</div>
1205
1206<!-- ======================================================================= -->
1207<div class="doc_subsection">
1208 <a name="datalayout">Data Layout</a>
1209</div>
1210
1211<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1213<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1214 data is to be laid out in memory. The syntax for the data layout is
1215 simply:</p>
1216
1217<div class="doc_code">
1218<pre>
1219target datalayout = "<i>layout specification</i>"
1220</pre>
1221</div>
1222
1223<p>The <i>layout specification</i> consists of a list of specifications
1224 separated by the minus sign character ('-'). Each specification starts with
1225 a letter and may include other information after the letter to define some
1226 aspect of the data layout. The specifications accepted are as follows:</p>
1227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1228<dl>
1229 <dt><tt>E</tt></dt>
1230 <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]1231 bits with the most significance have the lowest address location.</dd>
1232
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1233 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1234 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1235 the bits with the least significance have the lowest address
1236 location.</dd>
1237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1238 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1239 <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]1240 <i>preferred</i> alignments. All sizes are in bits. Specifying
1241 the <i>pref</i> alignment is optional. If omitted, the
1242 preceding <tt>:</tt> should be omitted too.</dd>
1243
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1244 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1245 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1246 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1247
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1248 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1249 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1250 <i>size</i>.</dd>
1251
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1252 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1253 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1254 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1255 (double).</dd>
1256
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1257 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1258 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1259 <i>size</i>.</dd>
1260
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1261 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1262 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1263 <i>size</i>.</dd>
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1264
1265 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1266 <dd>This specifies a set of native integer widths for the target CPU
1267 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1268 "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]1269 this set are considered to support most general arithmetic
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1270 operations efficiently.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1271</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1272
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1273<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1274 default set of specifications which are then (possibly) overriden by the
1275 specifications in the <tt>datalayout</tt> keyword. The default specifications
1276 are given in this list:</p>
1277
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1278<ul>
1279 <li><tt>E</tt> - big endian</li>
1280 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1281 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1282 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1283 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1284 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1285 <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]1286 alignment of 64-bits</li>
1287 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1288 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1289 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1290 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1291 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1292 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1293</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1294
1295<p>When LLVM is determining the alignment for a given type, it uses the
1296 following rules:</p>
1297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1298<ol>
1299 <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]1300 specification is used.</li>
1301
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1302 <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]1303 smallest integer type that is larger than the bitwidth of the sought type
1304 is used. If none of the specifications are larger than the bitwidth then
1305 the the largest integer type is used. For example, given the default
1306 specifications above, the i7 type will use the alignment of i8 (next
1307 largest) while both i65 and i256 will use the alignment of i64 (largest
1308 specified).</li>
1309
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1310 <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]1311 largest vector type that is smaller than the sought vector type will be
1312 used as a fall back. This happens because &lt;128 x double&gt; can be
1313 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1314</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1315
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1316</div>
1317
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1318<!-- ======================================================================= -->
1319<div class="doc_subsection">
1320 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1321</div>
1322
1323<div class="doc_text">
1324
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1325<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1326with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1327is undefined. Pointer values are associated with address ranges
1328according to the following rules:</p>
1329
1330<ul>
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1331 <li>A pointer value formed from a
1332 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1333 is associated with the addresses associated with the first operand
1334 of the <tt>getelementptr</tt>.</li>
1335 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1336 range of the variable's storage.</li>
1337 <li>The result value of an allocation instruction is associated with
1338 the address range of the allocated storage.</li>
1339 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1340 no address.</li>
1341 <li>A pointer value formed by an
1342 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1343 address ranges of all pointer values that contribute (directly or
1344 indirectly) to the computation of the pointer's value.</li>
1345 <li>The result value of a
1346 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1347 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1348 <li>An integer constant other than zero or a pointer value returned
1349 from a function not defined within LLVM may be associated with address
1350 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1351 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1352 allocated by mechanisms provided by LLVM.</li>
1353 </ul>
1354
1355<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1356<tt><a href="#i_load">load</a></tt> merely indicates the size and
1357alignment of the memory from which to load, as well as the
1358interpretation of the value. The first operand of a
1359<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1360and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1361
1362<p>Consequently, type-based alias analysis, aka TBAA, aka
1363<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1364LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1365additional information which specialized optimization passes may use
1366to implement type-based alias analysis.</p>
1367
1368</div>
1369
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1370<!-- *********************************************************************** -->
1371<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1372<!-- *********************************************************************** -->
1373
1374<div class="doc_text">
1375
1376<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1377 intermediate representation. Being typed enables a number of optimizations
1378 to be performed on the intermediate representation directly, without having
1379 to do extra analyses on the side before the transformation. A strong type
1380 system makes it easier to read the generated code and enables novel analyses
1381 and transformations that are not feasible to perform on normal three address
1382 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1383
1384</div>
1385
1386<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1387<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1388Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1390<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1391
1392<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1393
1394<table border="1" cellspacing="0" cellpadding="4">
1395 <tbody>
1396 <tr><th>Classification</th><th>Types</th></tr>
1397 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1398 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1399 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1400 </tr>
1401 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1402 <td><a href="#t_floating">floating point</a></td>
1403 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1404 </tr>
1405 <tr>
1406 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1407 <td><a href="#t_integer">integer</a>,
1408 <a href="#t_floating">floating point</a>,
1409 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1410 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1411 <a href="#t_struct">structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1412 <a href="#t_union">union</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1413 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1414 <a href="#t_label">label</a>,
1415 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1416 </td>
1417 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1418 <tr>
1419 <td><a href="#t_primitive">primitive</a></td>
1420 <td><a href="#t_label">label</a>,
1421 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1422 <a href="#t_floating">floating point</a>,
1423 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1424 </tr>
1425 <tr>
1426 <td><a href="#t_derived">derived</a></td>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1427 <td><a href="#t_array">array</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1428 <a href="#t_function">function</a>,
1429 <a href="#t_pointer">pointer</a>,
1430 <a href="#t_struct">structure</a>,
1431 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1432 <a href="#t_union">union</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1433 <a href="#t_vector">vector</a>,
1434 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1435 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1436 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1437 </tbody>
1438</table>
1439
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1440<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1441 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1442 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1443
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1444</div>
1445
1446<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1447<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1448
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1449<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1450
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1451<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1452 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1453
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1454</div>
1455
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1456<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1457<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1458
1459<div class="doc_text">
1460
1461<h5>Overview:</h5>
1462<p>The integer type is a very simple type that simply specifies an arbitrary
1463 bit width for the integer type desired. Any bit width from 1 bit to
1464 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1465
1466<h5>Syntax:</h5>
1467<pre>
1468 iN
1469</pre>
1470
1471<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1472 value.</p>
1473
1474<h5>Examples:</h5>
1475<table class="layout">
1476 <tr class="layout">
1477 <td class="left"><tt>i1</tt></td>
1478 <td class="left">a single-bit integer.</td>
1479 </tr>
1480 <tr class="layout">
1481 <td class="left"><tt>i32</tt></td>
1482 <td class="left">a 32-bit integer.</td>
1483 </tr>
1484 <tr class="layout">
1485 <td class="left"><tt>i1942652</tt></td>
1486 <td class="left">a really big integer of over 1 million bits.</td>
1487 </tr>
1488</table>
1489
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1490</div>
1491
1492<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1493<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1494
1495<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1496
1497<table>
1498 <tbody>
1499 <tr><th>Type</th><th>Description</th></tr>
1500 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1501 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1502 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1503 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1504 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1505 </tbody>
1506</table>
1507
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1508</div>
1509
1510<!-- _______________________________________________________________________ -->
1511<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1512
1513<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1514
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1515<h5>Overview:</h5>
1516<p>The void type does not represent any value and has no size.</p>
1517
1518<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1519<pre>
1520 void
1521</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1522
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1523</div>
1524
1525<!-- _______________________________________________________________________ -->
1526<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1527
1528<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1529
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1530<h5>Overview:</h5>
1531<p>The label type represents code labels.</p>
1532
1533<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1534<pre>
1535 label
1536</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1537
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1538</div>
1539
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1540<!-- _______________________________________________________________________ -->
1541<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1542
1543<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1544
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1545<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1546<p>The metadata type represents embedded metadata. No derived types may be
1547 created from metadata except for <a href="#t_function">function</a>
1548 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1549
1550<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1551<pre>
1552 metadata
1553</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1554
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1555</div>
1556
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1557
1558<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1559<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1560
1561<div class="doc_text">
1562
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1563<p>The real power in LLVM comes from the derived types in the system. This is
1564 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1565 useful types. Each of these types contain one or more element types which
1566 may be a primitive type, or another derived type. For example, it is
1567 possible to have a two dimensional array, using an array as the element type
1568 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1569
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1570
1571</div>
1572
1573<!-- _______________________________________________________________________ -->
1574<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1575
1576<div class="doc_text">
1577
1578<p>Aggregate Types are a subset of derived types that can contain multiple
1579 member types. <a href="#t_array">Arrays</a>,
1580 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1581 <a href="#t_union">unions</a> are aggregate types.</p>
1582
1583</div>
1584
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1585</div>
1586
1587<!-- _______________________________________________________________________ -->
1588<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1589
1590<div class="doc_text">
1591
1592<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1593<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1594 sequentially in memory. The array type requires a size (number of elements)
1595 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1596
1597<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1598<pre>
1599 [&lt;# elements&gt; x &lt;elementtype&gt;]
1600</pre>
1601
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1602<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1603 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1604
1605<h5>Examples:</h5>
1606<table class="layout">
1607 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1608 <td class="left"><tt>[40 x i32]</tt></td>
1609 <td class="left">Array of 40 32-bit integer values.</td>
1610 </tr>
1611 <tr class="layout">
1612 <td class="left"><tt>[41 x i32]</tt></td>
1613 <td class="left">Array of 41 32-bit integer values.</td>
1614 </tr>
1615 <tr class="layout">
1616 <td class="left"><tt>[4 x i8]</tt></td>
1617 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1618 </tr>
1619</table>
1620<p>Here are some examples of multidimensional arrays:</p>
1621<table class="layout">
1622 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1623 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1624 <td class="left">3x4 array of 32-bit integer values.</td>
1625 </tr>
1626 <tr class="layout">
1627 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1628 <td class="left">12x10 array of single precision floating point values.</td>
1629 </tr>
1630 <tr class="layout">
1631 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1632 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1633 </tr>
1634</table>
1635
Dan Gohman87ec5ad2009-11-09 19:01:53 +0000[diff] [blame]1636<p>There is no restriction on indexing beyond the end of the array implied by
1637 a static type (though there are restrictions on indexing beyond the bounds
1638 of an allocated object in some cases). This means that single-dimension
1639 'variable sized array' addressing can be implemented in LLVM with a zero
1640 length array type. An implementation of 'pascal style arrays' in LLVM could
1641 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1642
1643</div>
1644
1645<!-- _______________________________________________________________________ -->
1646<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1647
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1648<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1650<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1651<p>The function type can be thought of as a function signature. It consists of
1652 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]1653 function type is a scalar type, a void type, a struct type, or a union
1654 type. If the return type is a struct type then all struct elements must be
1655 of first class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1656
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1657<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1658<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1659 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1660</pre>
1661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1662<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]1663 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1664 which indicates that the function takes a variable number of arguments.
1665 Variable argument functions can access their arguments with
1666 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1667 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1668 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1669
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1670<h5>Examples:</h5>
1671<table class="layout">
1672 <tr class="layout">
1673 <td class="left"><tt>i32 (i32)</tt></td>
1674 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1675 </td>
1676 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1677 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1678 </tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1679 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1680 an <tt>i16</tt> that should be sign extended and a
1681 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1682 <tt>float</tt>.
1683 </td>
1684 </tr><tr class="layout">
1685 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1686 <td class="left">A vararg function that takes at least one
1687 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1688 which returns an integer. This is the signature for <tt>printf</tt> in
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1689 LLVM.
1690 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1691 </tr><tr class="layout">
1692 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1693 <td class="left">A function taking an <tt>i32</tt>, returning a
1694 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1695 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1696 </tr>
1697</table>
1698
1699</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1700
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1701<!-- _______________________________________________________________________ -->
1702<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1703
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1704<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1705
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1706<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1707<p>The structure type is used to represent a collection of data members together
1708 in memory. The packing of the field types is defined to match the ABI of the
1709 underlying processor. The elements of a structure may be any type that has a
1710 size.</p>
1711
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]1712<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1713 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1714 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1715 Structures in registers are accessed using the
1716 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1717 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1718<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1719<pre>
1720 { &lt;type list&gt; }
1721</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1722
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1723<h5>Examples:</h5>
1724<table class="layout">
1725 <tr class="layout">
1726 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1727 <td class="left">A triple of three <tt>i32</tt> values</td>
1728 </tr><tr class="layout">
1729 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1730 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1731 second element is a <a href="#t_pointer">pointer</a> to a
1732 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1733 an <tt>i32</tt>.</td>
1734 </tr>
1735</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1736
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1737</div>
1738
1739<!-- _______________________________________________________________________ -->
1740<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1741</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1742
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1743<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1744
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1745<h5>Overview:</h5>
1746<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1747 together in memory. There is no padding between fields. Further, the
1748 alignment of a packed structure is 1 byte. The elements of a packed
1749 structure may be any type that has a size.</p>
1750
1751<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1752 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1753 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1754
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1755<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1756<pre>
1757 &lt; { &lt;type list&gt; } &gt;
1758</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1759
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1760<h5>Examples:</h5>
1761<table class="layout">
1762 <tr class="layout">
1763 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1764 <td class="left">A triple of three <tt>i32</tt> values</td>
1765 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1766 <td class="left">
1767<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1768 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1769 second element is a <a href="#t_pointer">pointer</a> to a
1770 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1771 an <tt>i32</tt>.</td>
1772 </tr>
1773</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1774
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1775</div>
1776
1777<!-- _______________________________________________________________________ -->
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1778<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1779
1780<div class="doc_text">
1781
1782<h5>Overview:</h5>
1783<p>A union type describes an object with size and alignment suitable for
1784 an object of any one of a given set of types (also known as an "untagged"
1785 union). It is similar in concept and usage to a
1786 <a href="#t_struct">struct</a>, except that all members of the union
1787 have an offset of zero. The elements of a union may be any type that has a
1788 size. Unions must have at least one member - empty unions are not allowed.
1789 </p>
1790
1791<p>The size of the union as a whole will be the size of its largest member,
1792 and the alignment requirements of the union as a whole will be the largest
1793 alignment requirement of any member.</p>
1794
1795<p>Unions members are accessed using '<tt><a href="#i_load">load</a></tt> and
1796 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1797 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1798 Since all members are at offset zero, the getelementptr instruction does
1799 not affect the address, only the type of the resulting pointer.</p>
1800
1801<h5>Syntax:</h5>
1802<pre>
1803 union { &lt;type list&gt; }
1804</pre>
1805
1806<h5>Examples:</h5>
1807<table class="layout">
1808 <tr class="layout">
1809 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1810 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1811 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1812 </tr><tr class="layout">
1813 <td class="left">
1814 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1815 <td class="left">A union, where the first element is a <tt>float</tt> and the
1816 second element is a <a href="#t_pointer">pointer</a> to a
1817 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1818 an <tt>i32</tt>.</td>
1819 </tr>
1820</table>
1821
1822</div>
1823
1824<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1825<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1826
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1827<div class="doc_text">
1828
1829<h5>Overview:</h5>
1830<p>As in many languages, the pointer type represents a pointer or reference to
1831 another object, which must live in memory. Pointer types may have an optional
1832 address space attribute defining the target-specific numbered address space
1833 where the pointed-to object resides. The default address space is zero.</p>
1834
1835<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1836 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1838<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1839<pre>
1840 &lt;type&gt; *
1841</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1842
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1843<h5>Examples:</h5>
1844<table class="layout">
1845 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1846 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1847 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1848 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1849 </tr>
1850 <tr class="layout">
1851 <td class="left"><tt>i32 (i32 *) *</tt></td>
1852 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1853 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1854 <tt>i32</tt>.</td>
1855 </tr>
1856 <tr class="layout">
1857 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1858 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1859 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1860 </tr>
1861</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1862
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1863</div>
1864
1865<!-- _______________________________________________________________________ -->
1866<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1867
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1868<div class="doc_text">
1869
1870<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1871<p>A vector type is a simple derived type that represents a vector of elements.
1872 Vector types are used when multiple primitive data are operated in parallel
1873 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands87598b02009-11-27 13:38:03 +0000[diff] [blame]1874 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1875 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1876
1877<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1878<pre>
1879 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1880</pre>
1881
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1882<p>The number of elements is a constant integer value; elementtype may be any
1883 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1884
1885<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1886<table class="layout">
1887 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1888 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1889 <td class="left">Vector of 4 32-bit integer values.</td>
1890 </tr>
1891 <tr class="layout">
1892 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1893 <td class="left">Vector of 8 32-bit floating-point values.</td>
1894 </tr>
1895 <tr class="layout">
1896 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1897 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1898 </tr>
1899</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1900
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1901</div>
1902
1903<!-- _______________________________________________________________________ -->
1904<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1905<div class="doc_text">
1906
1907<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1908<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1909 corresponds (for example) to the C notion of a forward declared structure
1910 type. In LLVM, opaque types can eventually be resolved to any type (not just
1911 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1912
1913<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1914<pre>
1915 opaque
1916</pre>
1917
1918<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1919<table class="layout">
1920 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1921 <td class="left"><tt>opaque</tt></td>
1922 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1923 </tr>
1924</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1925
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1926</div>
1927
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1928<!-- ======================================================================= -->
1929<div class="doc_subsection">
1930 <a name="t_uprefs">Type Up-references</a>
1931</div>
1932
1933<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1934
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1935<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1936<p>An "up reference" allows you to refer to a lexically enclosing type without
1937 requiring it to have a name. For instance, a structure declaration may
1938 contain a pointer to any of the types it is lexically a member of. Example
1939 of up references (with their equivalent as named type declarations)
1940 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1941
1942<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1943 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1944 { \2 }* %y = type { %y }*
1945 \1* %z = type %z*
1946</pre>
1947
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1948<p>An up reference is needed by the asmprinter for printing out cyclic types
1949 when there is no declared name for a type in the cycle. Because the
1950 asmprinter does not want to print out an infinite type string, it needs a
1951 syntax to handle recursive types that have no names (all names are optional
1952 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1953
1954<h5>Syntax:</h5>
1955<pre>
1956 \&lt;level&gt;
1957</pre>
1958
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1959<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]1960
1961<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1962<table class="layout">
1963 <tr class="layout">
1964 <td class="left"><tt>\1*</tt></td>
1965 <td class="left">Self-referential pointer.</td>
1966 </tr>
1967 <tr class="layout">
1968 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1969 <td class="left">Recursive structure where the upref refers to the out-most
1970 structure.</td>
1971 </tr>
1972</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1973
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1974</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1975
1976<!-- *********************************************************************** -->
1977<div class="doc_section"> <a name="constants">Constants</a> </div>
1978<!-- *********************************************************************** -->
1979
1980<div class="doc_text">
1981
1982<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1983 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1984
1985</div>
1986
1987<!-- ======================================================================= -->
1988<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1989
1990<div class="doc_text">
1991
1992<dl>
1993 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1994 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1995 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1996
1997 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1998 <dd>Standard integers (such as '4') are constants of
1999 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2000 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2001
2002 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2003 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2004 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2005 notation (see below). The assembler requires the exact decimal value of a
2006 floating-point constant. For example, the assembler accepts 1.25 but
2007 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2008 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2009
2010 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2011 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2012 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2013</dl>
2014
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2015<p>The one non-intuitive notation for constants is the hexadecimal form of
2016 floating point constants. For example, the form '<tt>double
2017 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2018 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2019 constants are required (and the only time that they are generated by the
2020 disassembler) is when a floating point constant must be emitted but it cannot
2021 be represented as a decimal floating point number in a reasonable number of
2022 digits. For example, NaN's, infinities, and other special values are
2023 represented in their IEEE hexadecimal format so that assembly and disassembly
2024 do not cause any bits to change in the constants.</p>
2025
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]2026<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2027 represented using the 16-digit form shown above (which matches the IEEE754
2028 representation for double); float values must, however, be exactly
2029 representable as IEE754 single precision. Hexadecimal format is always used
2030 for long double, and there are three forms of long double. The 80-bit format
2031 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2032 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2033 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2034 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2035 currently supported target uses this format. Long doubles will only work if
2036 they match the long double format on your target. All hexadecimal formats
2037 are big-endian (sign bit at the left).</p>
2038
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2039</div>
2040
2041<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2042<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2043<a name="aggregateconstants"></a> <!-- old anchor -->
2044<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2045</div>
2046
2047<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2048
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2049<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2050 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2051
2052<dl>
2053 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2054 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2055 type definitions (a comma separated list of elements, surrounded by braces
2056 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2057 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2058 Structure constants must have <a href="#t_struct">structure type</a>, and
2059 the number and types of elements must match those specified by the
2060 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2061
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2062 <dt><b>Union constants</b></dt>
2063 <dd>Union constants are represented with notation similar to a structure with
2064 a single element - that is, a single typed element surrounded
2065 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2066 <a href="#t_union">union type</a> can be initialized with a single-element
2067 struct as long as the type of the struct element matches the type of
2068 one of the union members.</dd>
2069
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2070 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2071 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2072 definitions (a comma separated list of elements, surrounded by square
2073 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2074 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2075 the number and types of elements must match those specified by the
2076 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2077
2078 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2079 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2080 definitions (a comma separated list of elements, surrounded by
2081 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2082 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2083 have <a href="#t_vector">vector type</a>, and the number and types of
2084 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2085
2086 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2087 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2088 value to zero of <em>any</em> type, including scalar and
2089 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2090 This is often used to avoid having to print large zero initializers
2091 (e.g. for large arrays) and is always exactly equivalent to using explicit
2092 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2093
2094 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]2095 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2096 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2097 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2098 be interpreted as part of the instruction stream, metadata is a place to
2099 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2100</dl>
2101
2102</div>
2103
2104<!-- ======================================================================= -->
2105<div class="doc_subsection">
2106 <a name="globalconstants">Global Variable and Function Addresses</a>
2107</div>
2108
2109<div class="doc_text">
2110
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2111<p>The addresses of <a href="#globalvars">global variables</a>
2112 and <a href="#functionstructure">functions</a> are always implicitly valid
2113 (link-time) constants. These constants are explicitly referenced when
2114 the <a href="#identifiers">identifier for the global</a> is used and always
2115 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2116 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2117
2118<div class="doc_code">
2119<pre>
2120@X = global i32 17
2121@Y = global i32 42
2122@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2123</pre>
2124</div>
2125
2126</div>
2127
2128<!-- ======================================================================= -->
2129<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2130<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2131
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2132<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]2133 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2134 Undefined values may be of any type (other than label or void) and be used
2135 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2136
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2137<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2138 program is well defined no matter what value is used. This gives the
2139 compiler more freedom to optimize. Here are some examples of (potentially
2140 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2141
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2142
2143<div class="doc_code">
2144<pre>
2145 %A = add %X, undef
2146 %B = sub %X, undef
2147 %C = xor %X, undef
2148Safe:
2149 %A = undef
2150 %B = undef
2151 %C = undef
2152</pre>
2153</div>
2154
2155<p>This is safe because all of the output bits are affected by the undef bits.
2156Any output bit can have a zero or one depending on the input bits.</p>
2157
2158<div class="doc_code">
2159<pre>
2160 %A = or %X, undef
2161 %B = and %X, undef
2162Safe:
2163 %A = -1
2164 %B = 0
2165Unsafe:
2166 %A = undef
2167 %B = undef
2168</pre>
2169</div>
2170
2171<p>These logical operations have bits that are not always affected by the input.
2172For example, if "%X" has a zero bit, then the output of the 'and' operation will
2173always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2174such, 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]2175However, it is safe to assume that all bits of the undef could be 0, and
2176optimize the and to 0. Likewise, it is safe to assume that all the bits of
2177the 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]2178-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2179
2180<div class="doc_code">
2181<pre>
2182 %A = select undef, %X, %Y
2183 %B = select undef, 42, %Y
2184 %C = select %X, %Y, undef
2185Safe:
2186 %A = %X (or %Y)
2187 %B = 42 (or %Y)
2188 %C = %Y
2189Unsafe:
2190 %A = undef
2191 %B = undef
2192 %C = undef
2193</pre>
2194</div>
2195
2196<p>This set of examples show that undefined select (and conditional branch)
2197conditions can go "either way" but they have to come from one of the two
2198operands. In the %A example, if %X and %Y were both known to have a clear low
2199bit, then %A would have to have a cleared low bit. However, in the %C example,
2200the optimizer is allowed to assume that the undef operand could be the same as
2201%Y, allowing the whole select to be eliminated.</p>
2202
2203
2204<div class="doc_code">
2205<pre>
2206 %A = xor undef, undef
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2207
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2208 %B = undef
2209 %C = xor %B, %B
2210
2211 %D = undef
2212 %E = icmp lt %D, 4
2213 %F = icmp gte %D, 4
2214
2215Safe:
2216 %A = undef
2217 %B = undef
2218 %C = undef
2219 %D = undef
2220 %E = undef
2221 %F = undef
2222</pre>
2223</div>
2224
2225<p>This example points out that two undef operands are not necessarily the same.
2226This can be surprising to people (and also matches C semantics) where they
2227assume that "X^X" is always zero, even if X is undef. This isn't true for a
2228number of reasons, but the short answer is that an undef "variable" can
2229arbitrarily change its value over its "live range". This is true because the
2230"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2231logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2232so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2233to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2234would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2235
2236<div class="doc_code">
2237<pre>
2238 %A = fdiv undef, %X
2239 %B = fdiv %X, undef
2240Safe:
2241 %A = undef
2242b: unreachable
2243</pre>
2244</div>
2245
2246<p>These examples show the crucial difference between an <em>undefined
2247value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2248allowed to have an arbitrary bit-pattern. This means that the %A operation
2249can be constant folded to undef because the undef could be an SNaN, and fdiv is
2250not (currently) defined on SNaN's. However, in the second example, we can make
2251a more aggressive assumption: because the undef is allowed to be an arbitrary
2252value, 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]2253has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2254does not execute at all. This allows us to delete the divide and all code after
2255it: since the undefined operation "can't happen", the optimizer can assume that
2256it occurs in dead code.
2257</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2258
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2259<div class="doc_code">
2260<pre>
2261a: store undef -> %X
2262b: store %X -> undef
2263Safe:
2264a: &lt;deleted&gt;
2265b: unreachable
2266</pre>
2267</div>
2268
2269<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2270can be assumed to not have any effect: we can assume that the value is
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2271overwritten with bits that happen to match what was already there. However, a
2272store "to" an undefined location could clobber arbitrary memory, therefore, it
2273has undefined behavior.</p>
2274
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2275</div>
2276
2277<!-- ======================================================================= -->
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2278<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2279 Blocks</a></div>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2280<div class="doc_text">
2281
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2282<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2283
2284<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner24f2e852009-10-27 21:49:40 +0000[diff] [blame]2285 basic block in the specified function, and always has an i8* type. Taking
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2286 the address of the entry block is illegal.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2287
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2288<p>This value only has defined behavior when used as an operand to the
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2289 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2290 against null. Pointer equality tests between labels addresses is undefined
2291 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2292 equal to the null pointer. This may also be passed around as an opaque
2293 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner0bae7b32009-10-27 21:44:20 +0000[diff] [blame]2294 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2295 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2296
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2297<p>Finally, some targets may provide defined semantics when
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2298 using the value as the operand to an inline assembly, but that is target
2299 specific.
2300 </p>
2301
2302</div>
2303
2304
2305<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2306<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2307</div>
2308
2309<div class="doc_text">
2310
2311<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2312 to be used as constants. Constant expressions may be of
2313 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2314 operation that does not have side effects (e.g. load and call are not
2315 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2316
2317<dl>
2318 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2319 <dd>Truncate a constant to another type. The bit size of CST must be larger
2320 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2321
2322 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2323 <dd>Zero extend a constant to another type. The bit size of CST must be
2324 smaller or equal to the bit size of TYPE. Both types must be
2325 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2326
2327 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2328 <dd>Sign extend a constant to another type. The bit size of CST must be
2329 smaller or equal to the bit size of TYPE. Both types must be
2330 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2331
2332 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2333 <dd>Truncate a floating point constant to another floating point type. The
2334 size of CST must be larger than the size of TYPE. Both types must be
2335 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2336
2337 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2338 <dd>Floating point extend a constant to another type. The size of CST must be
2339 smaller or equal to the size of TYPE. Both types must be floating
2340 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2341
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2342 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2343 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2344 constant. TYPE must be a scalar or vector integer type. CST must be of
2345 scalar or vector floating point type. Both CST and TYPE must be scalars,
2346 or vectors of the same number of elements. If the value won't fit in the
2347 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2348
2349 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2350 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2351 constant. TYPE must be a scalar or vector integer type. CST must be of
2352 scalar or vector floating point type. Both CST and TYPE must be scalars,
2353 or vectors of the same number of elements. If the value won't fit in the
2354 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2355
2356 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2357 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2358 constant. TYPE must be a scalar or vector floating point type. CST must be
2359 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2360 vectors of the same number of elements. If the value won't fit in the
2361 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2362
2363 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2364 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2365 constant. TYPE must be a scalar or vector floating point type. CST must be
2366 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2367 vectors of the same number of elements. If the value won't fit in the
2368 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2369
2370 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2371 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2372 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2373 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2374 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2375
2376 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2377 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2378 type. CST must be of integer type. The CST value is zero extended,
2379 truncated, or unchanged to make it fit in a pointer size. This one is
2380 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2381
2382 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2383 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2384 are the same as those for the <a href="#i_bitcast">bitcast
2385 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2386
2387 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2388 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2389 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2390 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2391 instruction, the index list may have zero or more indexes, which are
2392 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2393
2394 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2395 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2396
2397 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2398 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2399
2400 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2401 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2402
2403 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2404 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2405 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2406
2407 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2408 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2409 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2410
2411 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2412 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2413 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2414
2415 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2416 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2417 be any of the <a href="#binaryops">binary</a>
2418 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2419 on operands are the same as those for the corresponding instruction
2420 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2421</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2422
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2423</div>
2424
2425<!-- *********************************************************************** -->
2426<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2427<!-- *********************************************************************** -->
2428
2429<!-- ======================================================================= -->
2430<div class="doc_subsection">
2431<a name="inlineasm">Inline Assembler Expressions</a>
2432</div>
2433
2434<div class="doc_text">
2435
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2436<p>LLVM supports inline assembler expressions (as opposed
2437 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2438 a special value. This value represents the inline assembler as a string
2439 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2440 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2441 expression has side effects, and a flag indicating whether the function
2442 containing the asm needs to align its stack conservatively. An example
2443 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2444
2445<div class="doc_code">
2446<pre>
2447i32 (i32) asm "bswap $0", "=r,r"
2448</pre>
2449</div>
2450
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2451<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2452 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2453 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2454
2455<div class="doc_code">
2456<pre>
2457%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2458</pre>
2459</div>
2460
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2461<p>Inline asms with side effects not visible in the constraint list must be
2462 marked as having side effects. This is done through the use of the
2463 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2464
2465<div class="doc_code">
2466<pre>
2467call void asm sideeffect "eieio", ""()
2468</pre>
2469</div>
2470
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2471<p>In some cases inline asms will contain code that will not work unless the
2472 stack is aligned in some way, such as calls or SSE instructions on x86,
2473 yet will not contain code that does that alignment within the asm.
2474 The compiler should make conservative assumptions about what the asm might
2475 contain and should generate its usual stack alignment code in the prologue
2476 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2477
2478<div class="doc_code">
2479<pre>
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2480call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2481</pre>
2482</div>
2483
2484<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2485 first.</p>
2486
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2487<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2488 documented here. Constraints on what can be done (e.g. duplication, moving,
2489 etc need to be documented). This is probably best done by reference to
2490 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2491
2492</div>
2493
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2494<!-- ======================================================================= -->
2495<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2496 Strings</a>
2497</div>
2498
2499<div class="doc_text">
2500
2501<p>LLVM IR allows metadata to be attached to instructions in the program that
2502 can convey extra information about the code to the optimizers and code
2503 generator. One example application of metadata is source-level debug
2504 information. There are two metadata primitives: strings and nodes. All
2505 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2506 preceding exclamation point ('<tt>!</tt>').</p>
2507
2508<p>A metadata string is a string surrounded by double quotes. It can contain
2509 any character by escaping non-printable characters with "\xx" where "xx" is
2510 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2511
2512<p>Metadata nodes are represented with notation similar to structure constants
2513 (a comma separated list of elements, surrounded by braces and preceded by an
2514 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2515 10}</tt>". Metadata nodes can have any values as their operand.</p>
2516
2517<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2518 metadata nodes, which can be looked up in the module symbol table. For
2519 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2520
2521</div>
2522
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2523
2524<!-- *********************************************************************** -->
2525<div class="doc_section">
2526 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2527</div>
2528<!-- *********************************************************************** -->
2529
2530<p>LLVM has a number of "magic" global variables that contain data that affect
2531code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2532of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2533section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2534by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2535
2536<!-- ======================================================================= -->
2537<div class="doc_subsection">
2538<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2539</div>
2540
2541<div class="doc_text">
2542
2543<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2544href="#linkage_appending">appending linkage</a>. This array contains a list of
2545pointers to global variables and functions which may optionally have a pointer
2546cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2547
2548<pre>
2549 @X = global i8 4
2550 @Y = global i32 123
2551
2552 @llvm.used = appending global [2 x i8*] [
2553 i8* @X,
2554 i8* bitcast (i32* @Y to i8*)
2555 ], section "llvm.metadata"
2556</pre>
2557
2558<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2559compiler, assembler, and linker are required to treat the symbol as if there is
2560a reference to the global that it cannot see. For example, if a variable has
2561internal linkage and no references other than that from the <tt>@llvm.used</tt>
2562list, it cannot be deleted. This is commonly used to represent references from
2563inline asms and other things the compiler cannot "see", and corresponds to
2564"attribute((used))" in GNU C.</p>
2565
2566<p>On some targets, the code generator must emit a directive to the assembler or
2567object file to prevent the assembler and linker from molesting the symbol.</p>
2568
2569</div>
2570
2571<!-- ======================================================================= -->
2572<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2573<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2574</div>
2575
2576<div class="doc_text">
2577
2578<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2579<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2580touching the symbol. On targets that support it, this allows an intelligent
2581linker to optimize references to the symbol without being impeded as it would be
2582by <tt>@llvm.used</tt>.</p>
2583
2584<p>This is a rare construct that should only be used in rare circumstances, and
2585should not be exposed to source languages.</p>
2586
2587</div>
2588
2589<!-- ======================================================================= -->
2590<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2591<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2592</div>
2593
2594<div class="doc_text">
2595
2596<p>TODO: Describe this.</p>
2597
2598</div>
2599
2600<!-- ======================================================================= -->
2601<div class="doc_subsection">
2602<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2603</div>
2604
2605<div class="doc_text">
2606
2607<p>TODO: Describe this.</p>
2608
2609</div>
2610
2611
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2612<!-- *********************************************************************** -->
2613<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2614<!-- *********************************************************************** -->
2615
2616<div class="doc_text">
2617
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2618<p>The LLVM instruction set consists of several different classifications of
2619 instructions: <a href="#terminators">terminator
2620 instructions</a>, <a href="#binaryops">binary instructions</a>,
2621 <a href="#bitwiseops">bitwise binary instructions</a>,
2622 <a href="#memoryops">memory instructions</a>, and
2623 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2624
2625</div>
2626
2627<!-- ======================================================================= -->
2628<div class="doc_subsection"> <a name="terminators">Terminator
2629Instructions</a> </div>
2630
2631<div class="doc_text">
2632
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2633<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2634 in a program ends with a "Terminator" instruction, which indicates which
2635 block should be executed after the current block is finished. These
2636 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2637 control flow, not values (the one exception being the
2638 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2639
2640<p>There are six different terminator instructions: the
2641 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2642 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2643 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendlingb4ae2292009-11-02 00:25:26 +0000[diff] [blame]2644 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2645 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2646 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2647 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2648
2649</div>
2650
2651<!-- _______________________________________________________________________ -->
2652<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2653Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2654
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2655<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2656
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2657<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2658<pre>
2659 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]2660 ret void <i>; Return from void function</i>
2661</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2663<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2664<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2665 a value) from a function back to the caller.</p>
2666
2667<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2668 value and then causes control flow, and one that just causes control flow to
2669 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2670
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2671<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2672<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2673 return value. The type of the return value must be a
2674 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2675
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2676<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2677 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2678 value or a return value with a type that does not match its type, or if it
2679 has a void return type and contains a '<tt>ret</tt>' instruction with a
2680 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2681
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2682<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2683<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2684 the calling function's context. If the caller is a
2685 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2686 instruction after the call. If the caller was an
2687 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2688 the beginning of the "normal" destination block. If the instruction returns
2689 a value, that value shall set the call or invoke instruction's return
2690 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2691
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2692<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2693<pre>
2694 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2695 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2696 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]2697</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2698
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2699</div>
2700<!-- _______________________________________________________________________ -->
2701<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2702
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2703<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2705<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2706<pre>
2707 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]2708</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2709
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2710<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2711<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2712 different basic block in the current function. There are two forms of this
2713 instruction, corresponding to a conditional branch and an unconditional
2714 branch.</p>
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 conditional branch form of the '<tt>br</tt>' instruction takes a single
2718 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2719 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2720 target.</p>
2721
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2722<h5>Semantics:</h5>
2723<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2724 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2725 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2726 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2727
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2728<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2729<pre>
2730Test:
2731 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2732 br i1 %cond, label %IfEqual, label %IfUnequal
2733IfEqual:
2734 <a href="#i_ret">ret</a> i32 1
2735IfUnequal:
2736 <a href="#i_ret">ret</a> i32 0
2737</pre>
2738
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2739</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2740
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2741<!-- _______________________________________________________________________ -->
2742<div class="doc_subsubsection">
2743 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2744</div>
2745
2746<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2747
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2748<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2749<pre>
2750 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2751</pre>
2752
2753<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2754<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]2755 several different places. It is a generalization of the '<tt>br</tt>'
2756 instruction, allowing a branch to occur to one of many possible
2757 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2758
2759<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2760<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2761 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2762 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2763 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2764
2765<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2766<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2767 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2768 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2769 transferred to the corresponding destination; otherwise, control flow is
2770 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2771
2772<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2773<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2774 <tt>switch</tt> instruction, this instruction may be code generated in
2775 different ways. For example, it could be generated as a series of chained
2776 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2777
2778<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2779<pre>
2780 <i>; Emulate a conditional br instruction</i>
2781 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2782 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2783
2784 <i>; Emulate an unconditional br instruction</i>
2785 switch i32 0, label %dest [ ]
2786
2787 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2788 switch i32 %val, label %otherwise [ i32 0, label %onzero
2789 i32 1, label %onone
2790 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2791</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2792
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2793</div>
2794
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2795
2796<!-- _______________________________________________________________________ -->
2797<div class="doc_subsubsection">
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2798 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2799</div>
2800
2801<div class="doc_text">
2802
2803<h5>Syntax:</h5>
2804<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2805 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]2806</pre>
2807
2808<h5>Overview:</h5>
2809
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2810<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2811 within the current function, whose address is specified by
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2812 "<tt>address</tt>". Address must be derived from a <a
2813 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2814
2815<h5>Arguments:</h5>
2816
2817<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2818 rest of the arguments indicate the full set of possible destinations that the
2819 address may point to. Blocks are allowed to occur multiple times in the
2820 destination list, though this isn't particularly useful.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2821
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2822<p>This destination list is required so that dataflow analysis has an accurate
2823 understanding of the CFG.</p>
2824
2825<h5>Semantics:</h5>
2826
2827<p>Control transfers to the block specified in the address argument. All
2828 possible destination blocks must be listed in the label list, otherwise this
2829 instruction has undefined behavior. This implies that jumps to labels
2830 defined in other functions have undefined behavior as well.</p>
2831
2832<h5>Implementation:</h5>
2833
2834<p>This is typically implemented with a jump through a register.</p>
2835
2836<h5>Example:</h5>
2837<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2838 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2839</pre>
2840
2841</div>
2842
2843
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2844<!-- _______________________________________________________________________ -->
2845<div class="doc_subsubsection">
2846 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2847</div>
2848
2849<div class="doc_text">
2850
2851<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2852<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2853 &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]2854 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2855</pre>
2856
2857<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2858<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2859 function, with the possibility of control flow transfer to either the
2860 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2861 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2862 control flow will return to the "normal" label. If the callee (or any
2863 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2864 instruction, control is interrupted and continued at the dynamically nearest
2865 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2866
2867<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2868<p>This instruction requires several arguments:</p>
2869
2870<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2871 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2872 convention</a> the call should use. If none is specified, the call
2873 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2874
2875 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2876 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2877 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2878
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2879 <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]2880 function value being invoked. In most cases, this is a direct function
2881 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2882 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2883
2884 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2885 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2886
2887 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2888 signature argument types. If the function signature indicates the
2889 function accepts a variable number of arguments, the extra arguments can
2890 be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2891
2892 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2893 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2894
2895 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2896 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2897
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2898 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2899 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2900 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2901</ol>
2902
2903<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2904<p>This instruction is designed to operate as a standard
2905 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2906 primary difference is that it establishes an association with a label, which
2907 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2908
2909<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2910 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2911 exception. Additionally, this is important for implementation of
2912 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2913
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2914<p>For the purposes of the SSA form, the definition of the value returned by the
2915 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2916 block to the "normal" label. If the callee unwinds then no return value is
2917 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2918
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]2919<p>Note that the code generator does not yet completely support unwind, and
2920that the invoke/unwind semantics are likely to change in future versions.</p>
2921
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2922<h5>Example:</h5>
2923<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2924 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2925 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2926 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2927 unwind label %TestCleanup <i>; {i32}:retval set</i>
2928</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2929
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2930</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2931
2932<!-- _______________________________________________________________________ -->
2933
2934<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2935Instruction</a> </div>
2936
2937<div class="doc_text">
2938
2939<h5>Syntax:</h5>
2940<pre>
2941 unwind
2942</pre>
2943
2944<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2945<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2946 at the first callee in the dynamic call stack which used
2947 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2948 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2949
2950<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2951<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2952 immediately halt. The dynamic call stack is then searched for the
2953 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2954 Once found, execution continues at the "exceptional" destination block
2955 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2956 instruction in the dynamic call chain, undefined behavior results.</p>
2957
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]2958<p>Note that the code generator does not yet completely support unwind, and
2959that the invoke/unwind semantics are likely to change in future versions.</p>
2960
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2961</div>
2962
2963<!-- _______________________________________________________________________ -->
2964
2965<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2966Instruction</a> </div>
2967
2968<div class="doc_text">
2969
2970<h5>Syntax:</h5>
2971<pre>
2972 unreachable
2973</pre>
2974
2975<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2976<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2977 instruction is used to inform the optimizer that a particular portion of the
2978 code is not reachable. This can be used to indicate that the code after a
2979 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2980
2981<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2982<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2983
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2984</div>
2985
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2986<!-- ======================================================================= -->
2987<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2988
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2989<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2990
2991<p>Binary operators are used to do most of the computation in a program. They
2992 require two operands of the same type, execute an operation on them, and
2993 produce a single value. The operands might represent multiple data, as is
2994 the case with the <a href="#t_vector">vector</a> data type. The result value
2995 has the same type as its operands.</p>
2996
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2997<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2998
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2999</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3000
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3001<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3002<div class="doc_subsubsection">
3003 <a name="i_add">'<tt>add</tt>' Instruction</a>
3004</div>
3005
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3006<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3007
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3008<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3009<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3010 &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]3011 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3012 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3013 &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]3014</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3015
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3016<h5>Overview:</h5>
3017<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3018
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3019<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3020<p>The two arguments to the '<tt>add</tt>' instruction must
3021 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3022 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3023
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3024<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3025<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3026
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3027<p>If the sum has unsigned overflow, the result returned is the mathematical
3028 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]3029
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3030<p>Because LLVM integers use a two's complement representation, this instruction
3031 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3032
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3033<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3034 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3035 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
3036 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3037
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3038<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3039<pre>
3040 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3041</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3042
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3043</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3044
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3045<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3046<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3047 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3048</div>
3049
3050<div class="doc_text">
3051
3052<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3053<pre>
3054 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3055</pre>
3056
3057<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3058<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3059
3060<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3061<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3062 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3063 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3064
3065<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3066<p>The value produced is the floating point sum of the two operands.</p>
3067
3068<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3069<pre>
3070 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3071</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3072
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3073</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3074
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3075<!-- _______________________________________________________________________ -->
3076<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3077 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3078</div>
3079
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3080<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3081
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3082<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3083<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3084 &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]3085 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3086 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3087 &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]3088</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3089
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3090<h5>Overview:</h5>
3091<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3092 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3093
3094<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3095 '<tt>neg</tt>' instruction present in most other intermediate
3096 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3097
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3098<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3099<p>The two arguments to the '<tt>sub</tt>' instruction must
3100 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3101 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3102
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3103<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3104<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3105
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3106<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3107 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3108 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3109
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3110<p>Because LLVM integers use a two's complement representation, this instruction
3111 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3112
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3113<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3114 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3115 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
3116 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3117
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3118<h5>Example:</h5>
3119<pre>
3120 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
3121 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
3122</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3123
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3124</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3125
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3126<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3127<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3128 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3129</div>
3130
3131<div class="doc_text">
3132
3133<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3134<pre>
3135 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3136</pre>
3137
3138<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3139<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3140 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3141
3142<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3143 '<tt>fneg</tt>' instruction present in most other intermediate
3144 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3145
3146<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]3147<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3148 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3149 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3150
3151<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3152<p>The value produced is the floating point difference of the two operands.</p>
3153
3154<h5>Example:</h5>
3155<pre>
3156 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3157 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3158</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3159
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3160</div>
3161
3162<!-- _______________________________________________________________________ -->
3163<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3164 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3165</div>
3166
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3167<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3168
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3169<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3170<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3171 &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]3172 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3173 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3174 &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]3175</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3176
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3177<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3178<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3179
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3180<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3181<p>The two arguments to the '<tt>mul</tt>' instruction must
3182 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3183 integer values. Both arguments must have identical types.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3184
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3185<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3186<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3187
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3188<p>If the result of the multiplication has unsigned overflow, the result
3189 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3190 width of the result.</p>
3191
3192<p>Because LLVM integers use a two's complement representation, and the result
3193 is the same width as the operands, this instruction returns the correct
3194 result for both signed and unsigned integers. If a full product
3195 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3196 be sign-extended or zero-extended as appropriate to the width of the full
3197 product.</p>
3198
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3199<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3200 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3201 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3202 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3203
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3204<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3205<pre>
3206 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3207</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3208
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3209</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3211<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3212<div class="doc_subsubsection">
3213 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3214</div>
3215
3216<div class="doc_text">
3217
3218<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3219<pre>
3220 &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]3221</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3222
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3223<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3224<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3225
3226<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3227<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3228 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3229 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3230
3231<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3232<p>The value produced is the floating point product of the two operands.</p>
3233
3234<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3235<pre>
3236 &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]3237</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3238
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3239</div>
3240
3241<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3242<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3243</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3244
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3245<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3246
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3247<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3248<pre>
3249 &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]3250</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3251
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3252<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3253<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3254
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3255<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3256<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3257 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3258 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3259
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3260<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3261<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3262
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3263<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3264 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3265
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3266<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3267
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3268<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3269<pre>
3270 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3271</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3272
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3273</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3274
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3275<!-- _______________________________________________________________________ -->
3276<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3277</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3279<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3280
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3281<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3282<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3283 &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]3284 &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]3285</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3286
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3287<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3288<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3289
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3290<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3291<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3292 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3293 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3294
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3295<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3296<p>The value produced is the signed integer quotient of the two operands rounded
3297 towards zero.</p>
3298
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3299<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3300 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3301
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3302<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3303 undefined behavior; this is a rare case, but can occur, for example, by doing
3304 a 32-bit division of -2147483648 by -1.</p>
3305
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3306<p>If the <tt>exact</tt> keyword is present, the result value of the
3307 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3308 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3309
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3310<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3311<pre>
3312 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3313</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3314
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3315</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3316
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3317<!-- _______________________________________________________________________ -->
3318<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3319Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3320
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3321<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3322
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3323<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3324<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3325 &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]3326</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3327
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3328<h5>Overview:</h5>
3329<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3330
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3331<h5>Arguments:</h5>
3332<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3333 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3334 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3335
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3336<h5>Semantics:</h5>
3337<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3338
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3339<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3340<pre>
3341 &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]3342</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3343
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3344</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3345
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3346<!-- _______________________________________________________________________ -->
3347<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3348</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3349
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3350<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3351
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3352<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3353<pre>
3354 &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]3355</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3356
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3357<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3358<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3359 division of its two arguments.</p>
3360
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3361<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3362<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3363 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3364 values. Both arguments must have identical types.</p>
3365
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3366<h5>Semantics:</h5>
3367<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3368 This instruction always performs an unsigned division to get the
3369 remainder.</p>
3370
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3371<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3372 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3373
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3374<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3375
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3376<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3377<pre>
3378 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3379</pre>
3380
3381</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3382
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3383<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3384<div class="doc_subsubsection">
3385 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3386</div>
3387
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3388<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3390<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3391<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3392 &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]3393</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3394
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3395<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3396<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3397 division of its two operands. This instruction can also take
3398 <a href="#t_vector">vector</a> versions of the values in which case the
3399 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3400
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3401<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3402<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3403 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3404 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3406<h5>Semantics:</h5>
3407<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3408 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3409 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3410 a value. For more information about the difference,
3411 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3412 Math Forum</a>. For a table of how this is implemented in various languages,
3413 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3414 Wikipedia: modulo operation</a>.</p>
3415
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3416<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3417 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3418
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3419<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3420 Overflow also leads to undefined behavior; this is a rare case, but can
3421 occur, for example, by taking the remainder of a 32-bit division of
3422 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3423 lets srem be implemented using instructions that return both the result of
3424 the division and the remainder.)</p>
3425
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3426<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3427<pre>
3428 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3429</pre>
3430
3431</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3432
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3433<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3434<div class="doc_subsubsection">
3435 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3436
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3437<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3438
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3439<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3440<pre>
3441 &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]3442</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3443
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3444<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3445<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3446 its two operands.</p>
3447
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3448<h5>Arguments:</h5>
3449<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3450 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3451 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3452
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3453<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3454<p>This instruction returns the <i>remainder</i> of a division. The remainder
3455 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3456
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3457<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3458<pre>
3459 &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]3460</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3461
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3462</div>
3463
3464<!-- ======================================================================= -->
3465<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3466Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3467
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3468<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3469
3470<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3471 program. They are generally very efficient instructions and can commonly be
3472 strength reduced from other instructions. They require two operands of the
3473 same type, execute an operation on them, and produce a single value. The
3474 resulting value is the same type as its operands.</p>
3475
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3476</div>
3477
3478<!-- _______________________________________________________________________ -->
3479<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3480Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3481
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3482<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3483
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3484<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3485<pre>
3486 &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]3487</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3488
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3489<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3490<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3491 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3492
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3493<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3494<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3495 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3496 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3497
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3498<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3499<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3500 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3501 is (statically or dynamically) negative or equal to or larger than the number
3502 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3503 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3504 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3505
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3506<h5>Example:</h5>
3507<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3508 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3509 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3510 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3511 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3512 &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]3513</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3514
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3515</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3516
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3517<!-- _______________________________________________________________________ -->
3518<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3519Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3520
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3521<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3522
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3523<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3524<pre>
3525 &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]3526</pre>
3527
3528<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3529<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3530 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3531
3532<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3533<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3534 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3535 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3536
3537<h5>Semantics:</h5>
3538<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3539 significant bits of the result will be filled with zero bits after the shift.
3540 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3541 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3542 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3543 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3544
3545<h5>Example:</h5>
3546<pre>
3547 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3548 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3549 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3550 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3551 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3552 &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]3553</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3554
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3555</div>
3556
3557<!-- _______________________________________________________________________ -->
3558<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3559Instruction</a> </div>
3560<div class="doc_text">
3561
3562<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3563<pre>
3564 &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]3565</pre>
3566
3567<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3568<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3569 operand shifted to the right a specified number of bits with sign
3570 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3571
3572<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3573<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3574 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3575 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3576
3577<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3578<p>This instruction always performs an arithmetic shift right operation, The
3579 most significant bits of the result will be filled with the sign bit
3580 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3581 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3582 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3583 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3584
3585<h5>Example:</h5>
3586<pre>
3587 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3588 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3589 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3590 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3591 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3592 &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]3593</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3594
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3595</div>
3596
3597<!-- _______________________________________________________________________ -->
3598<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3599Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3601<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3602
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3603<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3604<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3605 &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]3606</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3607
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3608<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3609<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3610 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3611
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3612<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3613<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3614 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3615 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3616
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3617<h5>Semantics:</h5>
3618<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3619
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3620<table border="1" cellspacing="0" cellpadding="4">
3621 <tbody>
3622 <tr>
3623 <td>In0</td>
3624 <td>In1</td>
3625 <td>Out</td>
3626 </tr>
3627 <tr>
3628 <td>0</td>
3629 <td>0</td>
3630 <td>0</td>
3631 </tr>
3632 <tr>
3633 <td>0</td>
3634 <td>1</td>
3635 <td>0</td>
3636 </tr>
3637 <tr>
3638 <td>1</td>
3639 <td>0</td>
3640 <td>0</td>
3641 </tr>
3642 <tr>
3643 <td>1</td>
3644 <td>1</td>
3645 <td>1</td>
3646 </tr>
3647 </tbody>
3648</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3650<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3651<pre>
3652 &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]3653 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3654 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3655</pre>
3656</div>
3657<!-- _______________________________________________________________________ -->
3658<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3659
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3660<div class="doc_text">
3661
3662<h5>Syntax:</h5>
3663<pre>
3664 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3665</pre>
3666
3667<h5>Overview:</h5>
3668<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3669 two operands.</p>
3670
3671<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3672<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3673 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3674 values. Both arguments must have identical types.</p>
3675
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3676<h5>Semantics:</h5>
3677<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3678
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3679<table border="1" cellspacing="0" cellpadding="4">
3680 <tbody>
3681 <tr>
3682 <td>In0</td>
3683 <td>In1</td>
3684 <td>Out</td>
3685 </tr>
3686 <tr>
3687 <td>0</td>
3688 <td>0</td>
3689 <td>0</td>
3690 </tr>
3691 <tr>
3692 <td>0</td>
3693 <td>1</td>
3694 <td>1</td>
3695 </tr>
3696 <tr>
3697 <td>1</td>
3698 <td>0</td>
3699 <td>1</td>
3700 </tr>
3701 <tr>
3702 <td>1</td>
3703 <td>1</td>
3704 <td>1</td>
3705 </tr>
3706 </tbody>
3707</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3708
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3709<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3710<pre>
3711 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3712 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3713 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3714</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3715
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3716</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3717
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3718<!-- _______________________________________________________________________ -->
3719<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3720Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3721
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3722<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3723
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3724<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3725<pre>
3726 &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]3727</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3728
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3729<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3730<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3731 its two operands. The <tt>xor</tt> is used to implement the "one's
3732 complement" operation, which is the "~" operator in C.</p>
3733
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3734<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3735<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3736 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3737 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3738
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3739<h5>Semantics:</h5>
3740<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3741
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3742<table border="1" cellspacing="0" cellpadding="4">
3743 <tbody>
3744 <tr>
3745 <td>In0</td>
3746 <td>In1</td>
3747 <td>Out</td>
3748 </tr>
3749 <tr>
3750 <td>0</td>
3751 <td>0</td>
3752 <td>0</td>
3753 </tr>
3754 <tr>
3755 <td>0</td>
3756 <td>1</td>
3757 <td>1</td>
3758 </tr>
3759 <tr>
3760 <td>1</td>
3761 <td>0</td>
3762 <td>1</td>
3763 </tr>
3764 <tr>
3765 <td>1</td>
3766 <td>1</td>
3767 <td>0</td>
3768 </tr>
3769 </tbody>
3770</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3771
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3772<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3773<pre>
3774 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3775 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3776 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3777 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3778</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3779
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3780</div>
3781
3782<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3783<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3784 <a name="vectorops">Vector Operations</a>
3785</div>
3786
3787<div class="doc_text">
3788
3789<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3790 target-independent manner. These instructions cover the element-access and
3791 vector-specific operations needed to process vectors effectively. While LLVM
3792 does directly support these vector operations, many sophisticated algorithms
3793 will want to use target-specific intrinsics to take full advantage of a
3794 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3795
3796</div>
3797
3798<!-- _______________________________________________________________________ -->
3799<div class="doc_subsubsection">
3800 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3801</div>
3802
3803<div class="doc_text">
3804
3805<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3806<pre>
3807 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3808</pre>
3809
3810<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3811<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3812 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3813
3814
3815<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3816<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3817 of <a href="#t_vector">vector</a> type. The second operand is an index
3818 indicating the position from which to extract the element. The index may be
3819 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3820
3821<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3822<p>The result is a scalar of the same type as the element type of
3823 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3824 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3825 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3826
3827<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3828<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3829 &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]3830</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3831
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3832</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3833
3834<!-- _______________________________________________________________________ -->
3835<div class="doc_subsubsection">
3836 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3837</div>
3838
3839<div class="doc_text">
3840
3841<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3842<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3843 &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]3844</pre>
3845
3846<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3847<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3848 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3849
3850<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3851<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3852 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3853 whose type must equal the element type of the first operand. The third
3854 operand is an index indicating the position at which to insert the value.
3855 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3856
3857<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3858<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3859 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3860 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3861 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3862
3863<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3864<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3865 &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]3866</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3867
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3868</div>
3869
3870<!-- _______________________________________________________________________ -->
3871<div class="doc_subsubsection">
3872 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3873</div>
3874
3875<div class="doc_text">
3876
3877<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3878<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3879 &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]3880</pre>
3881
3882<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3883<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3884 from two input vectors, returning a vector with the same element type as the
3885 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3886
3887<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3888<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3889 with types that match each other. The third argument is a shuffle mask whose
3890 element type is always 'i32'. The result of the instruction is a vector
3891 whose length is the same as the shuffle mask and whose element type is the
3892 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3893
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3894<p>The shuffle mask operand is required to be a constant vector with either
3895 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3896
3897<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3898<p>The elements of the two input vectors are numbered from left to right across
3899 both of the vectors. The shuffle mask operand specifies, for each element of
3900 the result vector, which element of the two input vectors the result element
3901 gets. The element selector may be undef (meaning "don't care") and the
3902 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3903
3904<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3905<pre>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3906 &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]3907 &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]3908 &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]3909 &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]3910 &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]3911 &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]3912 &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]3913 &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]3914</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3915
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3916</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3917
3918<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3919<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3920 <a name="aggregateops">Aggregate Operations</a>
3921</div>
3922
3923<div class="doc_text">
3924
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]3925<p>LLVM supports several instructions for working with
3926 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3927
3928</div>
3929
3930<!-- _______________________________________________________________________ -->
3931<div class="doc_subsubsection">
3932 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3933</div>
3934
3935<div class="doc_text">
3936
3937<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3938<pre>
3939 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3940</pre>
3941
3942<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]3943<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
3944 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3945
3946<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3947<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]3948 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
3949 <a href="#t_array">array</a> type. The operands are constant indices to
3950 specify which value to extract in a similar manner as indices in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3951 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3952
3953<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3954<p>The result is the value at the position in the aggregate specified by the
3955 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3956
3957<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3958<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3959 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3960</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3961
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3962</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3963
3964<!-- _______________________________________________________________________ -->
3965<div class="doc_subsubsection">
3966 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3967</div>
3968
3969<div class="doc_text">
3970
3971<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3972<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]3973 &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]3974</pre>
3975
3976<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]3977<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
3978 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3979
3980<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3981<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]3982 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
3983 <a href="#t_array">array</a> type. The second operand is a first-class
3984 value to insert. The following operands are constant indices indicating
3985 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]3986 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3987 value to insert must have the same type as the value identified by the
3988 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3989
3990<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3991<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3992 that of <tt>val</tt> except that the value at the position specified by the
3993 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3994
3995<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3996<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]3997 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
3998 %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]3999</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4000
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4001</div>
4002
4003
4004<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4005<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4006 <a name="memoryops">Memory Access and Addressing Operations</a>
4007</div>
4008
4009<div class="doc_text">
4010
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4011<p>A key design point of an SSA-based representation is how it represents
4012 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]4013 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4014 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4015
4016</div>
4017
4018<!-- _______________________________________________________________________ -->
4019<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4020 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4021</div>
4022
4023<div class="doc_text">
4024
4025<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4026<pre>
4027 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
4028</pre>
4029
4030<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4031<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4032 currently executing function, to be automatically released when this function
4033 returns to its caller. The object is always allocated in the generic address
4034 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4035
4036<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4037<p>The '<tt>alloca</tt>' instruction
4038 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4039 runtime stack, returning a pointer of the appropriate type to the program.
4040 If "NumElements" is specified, it is the number of elements allocated,
4041 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4042 specified, the value result of the allocation is guaranteed to be aligned to
4043 at least that boundary. If not specified, or if zero, the target can choose
4044 to align the allocation on any convenient boundary compatible with the
4045 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4046
4047<p>'<tt>type</tt>' may be any sized type.</p>
4048
4049<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]4050<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4051 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4052 memory is automatically released when the function returns. The
4053 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4054 variables that must have an address available. When the function returns
4055 (either with the <tt><a href="#i_ret">ret</a></tt>
4056 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4057 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4058
4059<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4060<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]4061 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4062 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4063 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4064 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4065</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4066
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4067</div>
4068
4069<!-- _______________________________________________________________________ -->
4070<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4071Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4072
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4073<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4074
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4075<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4076<pre>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4077 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>]
4078 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>]
4079 !<index> = !{ i32 1 }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4080</pre>
4081
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4082<h5>Overview:</h5>
4083<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4084
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4085<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4086<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4087 from which to load. The pointer must point to
4088 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4089 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
4090 number or order of execution of this <tt>load</tt> with other
4091 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4092 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4093
4094<p>The optional constant "align" argument specifies the alignment of the
4095 operation (that is, the alignment of the memory address). A value of 0 or an
4096 omitted "align" argument means that the operation has the preferential
4097 alignment for the target. It is the responsibility of the code emitter to
4098 ensure that the alignment information is correct. Overestimating the
4099 alignment results in an undefined behavior. Underestimating the alignment may
4100 produce less efficient code. An alignment of 1 is always safe.</p>
4101
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4102<p>The optional !nontemporal metadata must reference a single metatadata
4103 name <index> corresponding to a metadata node with one i32 entry of
4104 value 1. The existance of the !nontemporal metatadata on the
4105 instruction tells the optimizer and code generator that this load is
4106 not expected to be reused in the cache. The code generator may
4107 select special instructions to save cache bandwidth, such as the
4108 MOVNT intruction on x86.</p>
4109
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4110<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4111<p>The location of memory pointed to is loaded. If the value being loaded is of
4112 scalar type then the number of bytes read does not exceed the minimum number
4113 of bytes needed to hold all bits of the type. For example, loading an
4114 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4115 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4116 is undefined if the value was not originally written using a store of the
4117 same type.</p>
4118
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4119<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4120<pre>
4121 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4122 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4123 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
4124</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4125
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4126</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4127
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4128<!-- _______________________________________________________________________ -->
4129<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4130Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4131
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4132<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4133
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4134<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4135<pre>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4136 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !<index>] <i>; yields {void}</i>
4137 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]4138</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4139
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4140<h5>Overview:</h5>
4141<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4142
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4143<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4144<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4145 and an address at which to store it. The type of the
4146 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4147 the <a href="#t_firstclass">first class</a> type of the
4148 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4149 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4150 or order of execution of this <tt>store</tt> with other
4151 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4152 instructions.</p>
4153
4154<p>The optional constant "align" argument specifies the alignment of the
4155 operation (that is, the alignment of the memory address). A value of 0 or an
4156 omitted "align" argument means that the operation has the preferential
4157 alignment for the target. It is the responsibility of the code emitter to
4158 ensure that the alignment information is correct. Overestimating the
4159 alignment results in an undefined behavior. Underestimating the alignment may
4160 produce less efficient code. An alignment of 1 is always safe.</p>
4161
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4162<p>The optional !nontemporal metadata must reference a single metatadata
4163 name <index> corresponding to a metadata node with one i32 entry of
4164 value 1. The existance of the !nontemporal metatadata on the
4165 instruction tells the optimizer and code generator that this load is
4166 not expected to be reused in the cache. The code generator may
4167 select special instructions to save cache bandwidth, such as the
4168 MOVNT intruction on x86.</p>
4169
4170
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4171<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4172<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4173 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4174 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4175 does not exceed the minimum number of bytes needed to hold all bits of the
4176 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4177 writing a value of a type like <tt>i20</tt> with a size that is not an
4178 integral number of bytes, it is unspecified what happens to the extra bits
4179 that do not belong to the type, but they will typically be overwritten.</p>
4180
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4181<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4182<pre>
4183 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4184 store i32 3, i32* %ptr <i>; yields {void}</i>
4185 %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]4186</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4187
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4188</div>
4189
4190<!-- _______________________________________________________________________ -->
4191<div class="doc_subsubsection">
4192 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4193</div>
4194
4195<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4196
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4197<h5>Syntax:</h5>
4198<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4199 &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]4200 &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]4201</pre>
4202
4203<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4204<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4205 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4206 It performs address calculation only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4207
4208<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4209<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4210 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4211 elements of the aggregate object are indexed. The interpretation of each
4212 index is dependent on the type being indexed into. The first index always
4213 indexes the pointer value given as the first argument, the second index
4214 indexes a value of the type pointed to (not necessarily the value directly
4215 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4216 indexed into must be a pointer value, subsequent types can be arrays,
4217 vectors, structs and unions. Note that subsequent types being indexed into
4218 can never be pointers, since that would require loading the pointer before
4219 continuing calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4220
4221<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]4222 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4223 integer <b>constants</b> are allowed. When indexing into an array, pointer
4224 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]4225 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4226
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4227<p>For example, let's consider a C code fragment and how it gets compiled to
4228 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4229
4230<div class="doc_code">
4231<pre>
4232struct RT {
4233 char A;
4234 int B[10][20];
4235 char C;
4236};
4237struct ST {
4238 int X;
4239 double Y;
4240 struct RT Z;
4241};
4242
4243int *foo(struct ST *s) {
4244 return &amp;s[1].Z.B[5][13];
4245}
4246</pre>
4247</div>
4248
4249<p>The LLVM code generated by the GCC frontend is:</p>
4250
4251<div class="doc_code">
4252<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4253%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4254%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4255
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4256define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4257entry:
4258 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4259 ret i32* %reg
4260}
4261</pre>
4262</div>
4263
4264<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4265<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]4266 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4267 }</tt>' type, a structure. The second index indexes into the third element
4268 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4269 i8 }</tt>' type, another structure. The third index indexes into the second
4270 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4271 array. The two dimensions of the array are subscripted into, yielding an
4272 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4273 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4274
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4275<p>Note that it is perfectly legal to index partially through a structure,
4276 returning a pointer to an inner element. Because of this, the LLVM code for
4277 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4278
4279<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4280 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4281 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4282 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4283 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4284 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4285 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4286 ret i32* %t5
4287 }
4288</pre>
4289
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4290<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4291 <tt>getelementptr</tt> is undefined if the base pointer is not an
4292 <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]4293 that would be formed by successive addition of the offsets implied by the
4294 indices to the base address with infinitely precise arithmetic are not an
4295 <i>in bounds</i> address of that allocated object.
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4296 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4297 that point into the object, plus the address one byte past the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4298
4299<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4300 the base address with silently-wrapping two's complement arithmetic, and
4301 the result value of the <tt>getelementptr</tt> may be outside the object
4302 pointed to by the base pointer. The result value may not necessarily be
4303 used to access memory though, even if it happens to point into allocated
4304 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4305 section for more information.</p>
4306
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4307<p>The getelementptr instruction is often confusing. For some more insight into
4308 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4309
4310<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4311<pre>
4312 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4313 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4314 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4315 %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]4316 <i>; yields i8*:eptr</i>
4317 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4318 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4319 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4320</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4321
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4322</div>
4323
4324<!-- ======================================================================= -->
4325<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4326</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4327
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4328<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4329
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4330<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4331 which all take a single operand and a type. They perform various bit
4332 conversions on the operand.</p>
4333
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4334</div>
4335
4336<!-- _______________________________________________________________________ -->
4337<div class="doc_subsubsection">
4338 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4339</div>
4340<div class="doc_text">
4341
4342<h5>Syntax:</h5>
4343<pre>
4344 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4345</pre>
4346
4347<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4348<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4349 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4350
4351<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4352<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4353 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4354 size and type of the result, which must be
4355 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4356 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4357 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4358
4359<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4360<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4361 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4362 source size must be larger than the destination size, <tt>trunc</tt> cannot
4363 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4364
4365<h5>Example:</h5>
4366<pre>
4367 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4368 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4369 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4370</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4371
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4372</div>
4373
4374<!-- _______________________________________________________________________ -->
4375<div class="doc_subsubsection">
4376 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4377</div>
4378<div class="doc_text">
4379
4380<h5>Syntax:</h5>
4381<pre>
4382 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4383</pre>
4384
4385<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4386<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4387 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4388
4389
4390<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4391<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]4392 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4393 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]4394 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4395 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4396
4397<h5>Semantics:</h5>
4398<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]4399 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4400
4401<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4402
4403<h5>Example:</h5>
4404<pre>
4405 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4406 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4407</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4408
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4409</div>
4410
4411<!-- _______________________________________________________________________ -->
4412<div class="doc_subsubsection">
4413 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4414</div>
4415<div class="doc_text">
4416
4417<h5>Syntax:</h5>
4418<pre>
4419 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4420</pre>
4421
4422<h5>Overview:</h5>
4423<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4424
4425<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4426<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]4427 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4428 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]4429 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4430 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4431
4432<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4433<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4434 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4435 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4436
4437<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4438
4439<h5>Example:</h5>
4440<pre>
4441 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4442 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4443</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4444
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4445</div>
4446
4447<!-- _______________________________________________________________________ -->
4448<div class="doc_subsubsection">
4449 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4450</div>
4451
4452<div class="doc_text">
4453
4454<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4455<pre>
4456 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4457</pre>
4458
4459<h5>Overview:</h5>
4460<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4461 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4462
4463<h5>Arguments:</h5>
4464<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4465 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4466 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]4467 <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]4468 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4469
4470<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4471<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4472 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4473 <a href="#t_floating">floating point</a> type. If the value cannot fit
4474 within the destination type, <tt>ty2</tt>, then the results are
4475 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4476
4477<h5>Example:</h5>
4478<pre>
4479 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4480 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4481</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4482
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4483</div>
4484
4485<!-- _______________________________________________________________________ -->
4486<div class="doc_subsubsection">
4487 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4488</div>
4489<div class="doc_text">
4490
4491<h5>Syntax:</h5>
4492<pre>
4493 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4494</pre>
4495
4496<h5>Overview:</h5>
4497<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]4498 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4499
4500<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4501<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4502 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4503 a <a href="#t_floating">floating point</a> type to cast it to. The source
4504 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4505
4506<h5>Semantics:</h5>
4507<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4508 <a href="#t_floating">floating point</a> type to a larger
4509 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4510 used to make a <i>no-op cast</i> because it always changes bits. Use
4511 <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]4512
4513<h5>Example:</h5>
4514<pre>
4515 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4516 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4517</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4518
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4519</div>
4520
4521<!-- _______________________________________________________________________ -->
4522<div class="doc_subsubsection">
4523 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4524</div>
4525<div class="doc_text">
4526
4527<h5>Syntax:</h5>
4528<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4529 &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]4530</pre>
4531
4532<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4533<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4534 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4535
4536<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4537<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4538 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4539 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4540 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4541 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4542
4543<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4544<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4545 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4546 towards zero) unsigned integer value. If the value cannot fit
4547 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4548
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4549<h5>Example:</h5>
4550<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4551 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4552 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4553 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4554</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4555
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4556</div>
4557
4558<!-- _______________________________________________________________________ -->
4559<div class="doc_subsubsection">
4560 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4561</div>
4562<div class="doc_text">
4563
4564<h5>Syntax:</h5>
4565<pre>
4566 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4567</pre>
4568
4569<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4570<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4571 <a href="#t_floating">floating point</a> <tt>value</tt> to
4572 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4573
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4574<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4575<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4576 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4577 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4578 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4579 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4580
4581<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4582<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4583 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4584 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4585 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4586
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4587<h5>Example:</h5>
4588<pre>
4589 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4590 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4591 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4592</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4593
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4594</div>
4595
4596<!-- _______________________________________________________________________ -->
4597<div class="doc_subsubsection">
4598 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4599</div>
4600<div class="doc_text">
4601
4602<h5>Syntax:</h5>
4603<pre>
4604 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4605</pre>
4606
4607<h5>Overview:</h5>
4608<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4609 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4610
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4611<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4612<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]4613 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4614 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4615 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4616 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4617
4618<h5>Semantics:</h5>
4619<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4620 integer quantity and converts it to the corresponding floating point
4621 value. If the value cannot fit in the floating point value, the results are
4622 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4624<h5>Example:</h5>
4625<pre>
4626 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4627 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4628</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4629
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4630</div>
4631
4632<!-- _______________________________________________________________________ -->
4633<div class="doc_subsubsection">
4634 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4635</div>
4636<div class="doc_text">
4637
4638<h5>Syntax:</h5>
4639<pre>
4640 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4641</pre>
4642
4643<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4644<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4645 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4646
4647<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4648<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]4649 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4650 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4651 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4652 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4653
4654<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4655<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4656 quantity and converts it to the corresponding floating point value. If the
4657 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4658
4659<h5>Example:</h5>
4660<pre>
4661 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4662 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4663</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4664
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4665</div>
4666
4667<!-- _______________________________________________________________________ -->
4668<div class="doc_subsubsection">
4669 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4670</div>
4671<div class="doc_text">
4672
4673<h5>Syntax:</h5>
4674<pre>
4675 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4676</pre>
4677
4678<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4679<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4680 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4681
4682<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4683<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4684 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4685 <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]4686
4687<h5>Semantics:</h5>
4688<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4689 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4690 truncating or zero extending that value to the size of the integer type. If
4691 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4692 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4693 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4694 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4695
4696<h5>Example:</h5>
4697<pre>
4698 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4699 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4700</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4701
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4702</div>
4703
4704<!-- _______________________________________________________________________ -->
4705<div class="doc_subsubsection">
4706 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4707</div>
4708<div class="doc_text">
4709
4710<h5>Syntax:</h5>
4711<pre>
4712 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4713</pre>
4714
4715<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4716<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4717 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4718
4719<h5>Arguments:</h5>
4720<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4721 value to cast, and a type to cast it to, which must be a
4722 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4723
4724<h5>Semantics:</h5>
4725<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4726 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4727 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4728 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4729 than the size of a pointer then a zero extension is done. If they are the
4730 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4731
4732<h5>Example:</h5>
4733<pre>
4734 %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]4735 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4736 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4737</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4738
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4739</div>
4740
4741<!-- _______________________________________________________________________ -->
4742<div class="doc_subsubsection">
4743 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4744</div>
4745<div class="doc_text">
4746
4747<h5>Syntax:</h5>
4748<pre>
4749 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4750</pre>
4751
4752<h5>Overview:</h5>
4753<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4754 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4755
4756<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4757<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4758 non-aggregate first class value, and a type to cast it to, which must also be
4759 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4760 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4761 identical. If the source type is a pointer, the destination type must also be
4762 a pointer. This instruction supports bitwise conversion of vectors to
4763 integers and to vectors of other types (as long as they have the same
4764 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4765
4766<h5>Semantics:</h5>
4767<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4768 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4769 this conversion. The conversion is done as if the <tt>value</tt> had been
4770 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4771 be converted to other pointer types with this instruction. To convert
4772 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4773 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4774
4775<h5>Example:</h5>
4776<pre>
4777 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4778 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4779 %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]4780</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4781
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4782</div>
4783
4784<!-- ======================================================================= -->
4785<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4786
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4787<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4788
4789<p>The instructions in this category are the "miscellaneous" instructions, which
4790 defy better classification.</p>
4791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4792</div>
4793
4794<!-- _______________________________________________________________________ -->
4795<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4796</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4797
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4798<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4799
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4800<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4801<pre>
4802 &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]4803</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4804
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4805<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4806<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4807 boolean values based on comparison of its two integer, integer vector, or
4808 pointer operands.</p>
4809
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4810<h5>Arguments:</h5>
4811<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4812 the condition code indicating the kind of comparison to perform. It is not a
4813 value, just a keyword. The possible condition code are:</p>
4814
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4815<ol>
4816 <li><tt>eq</tt>: equal</li>
4817 <li><tt>ne</tt>: not equal </li>
4818 <li><tt>ugt</tt>: unsigned greater than</li>
4819 <li><tt>uge</tt>: unsigned greater or equal</li>
4820 <li><tt>ult</tt>: unsigned less than</li>
4821 <li><tt>ule</tt>: unsigned less or equal</li>
4822 <li><tt>sgt</tt>: signed greater than</li>
4823 <li><tt>sge</tt>: signed greater or equal</li>
4824 <li><tt>slt</tt>: signed less than</li>
4825 <li><tt>sle</tt>: signed less or equal</li>
4826</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4827
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4828<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4829 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4830 typed. They must also be identical types.</p>
4831
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4832<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4833<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4834 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4835 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]4836 result, as follows:</p>
4837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4838<ol>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4839 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4840 <tt>false</tt> otherwise. No sign interpretation is necessary or
4841 performed.</li>
4842
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4843 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4844 <tt>false</tt> otherwise. No sign interpretation is necessary or
4845 performed.</li>
4846
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4847 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4848 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4849
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4850 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4851 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4852 to <tt>op2</tt>.</li>
4853
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4854 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4855 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4856
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4857 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4858 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4859
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4860 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4861 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4862
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4863 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4864 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4865 to <tt>op2</tt>.</li>
4866
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4867 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4868 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4869
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4870 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4871 <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]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>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4875 values are compared as if they were integers.</p>
4876
4877<p>If the operands are integer vectors, then they are compared element by
4878 element. The result is an <tt>i1</tt> vector with the same number of elements
4879 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4880
4881<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4882<pre>
4883 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4884 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4885 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4886 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4887 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4888 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4889</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4890
4891<p>Note that the code generator does not yet support vector types with
4892 the <tt>icmp</tt> instruction.</p>
4893
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4894</div>
4895
4896<!-- _______________________________________________________________________ -->
4897<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4898</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4899
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4900<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4901
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4902<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4903<pre>
4904 &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]4905</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4906
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4907<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4908<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4909 values based on comparison of its operands.</p>
4910
4911<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]4912(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4913
4914<p>If the operands are floating point vectors, then the result type is a vector
4915 of boolean with the same number of elements as the operands being
4916 compared.</p>
4917
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4918<h5>Arguments:</h5>
4919<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4920 the condition code indicating the kind of comparison to perform. It is not a
4921 value, just a keyword. The possible condition code are:</p>
4922
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4923<ol>
4924 <li><tt>false</tt>: no comparison, always returns false</li>
4925 <li><tt>oeq</tt>: ordered and equal</li>
4926 <li><tt>ogt</tt>: ordered and greater than </li>
4927 <li><tt>oge</tt>: ordered and greater than or equal</li>
4928 <li><tt>olt</tt>: ordered and less than </li>
4929 <li><tt>ole</tt>: ordered and less than or equal</li>
4930 <li><tt>one</tt>: ordered and not equal</li>
4931 <li><tt>ord</tt>: ordered (no nans)</li>
4932 <li><tt>ueq</tt>: unordered or equal</li>
4933 <li><tt>ugt</tt>: unordered or greater than </li>
4934 <li><tt>uge</tt>: unordered or greater than or equal</li>
4935 <li><tt>ult</tt>: unordered or less than </li>
4936 <li><tt>ule</tt>: unordered or less than or equal</li>
4937 <li><tt>une</tt>: unordered or not equal</li>
4938 <li><tt>uno</tt>: unordered (either nans)</li>
4939 <li><tt>true</tt>: no comparison, always returns true</li>
4940</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4941
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4942<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4943 <i>unordered</i> means that either operand may be a QNAN.</p>
4944
4945<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4946 a <a href="#t_floating">floating point</a> type or
4947 a <a href="#t_vector">vector</a> of floating point type. They must have
4948 identical types.</p>
4949
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4950<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4951<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4952 according to the condition code given as <tt>cond</tt>. If the operands are
4953 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4954 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4955 follows:</p>
4956
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4957<ol>
4958 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4959
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4960 <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]4961 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4962
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4963 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4964 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4965
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4966 <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]4967 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4968
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4969 <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]4970 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4971
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4972 <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]4973 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4974
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4975 <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]4976 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4977
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4978 <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]4979
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4980 <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]4981 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4982
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4983 <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]4984 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4985
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4986 <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]4987 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4988
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4989 <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]4990 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4991
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4992 <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]4993 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4994
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4995 <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]4996 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4997
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4998 <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]4999
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5000 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5001</ol>
5002
5003<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5004<pre>
5005 &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]5006 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5007 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5008 &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]5009</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5010
5011<p>Note that the code generator does not yet support vector types with
5012 the <tt>fcmp</tt> instruction.</p>
5013
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5014</div>
5015
5016<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]5017<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5018 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5019</div>
5020
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5021<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5022
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5023<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5024<pre>
5025 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5026</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5027
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5028<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5029<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5030 SSA graph representing the function.</p>
5031
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5032<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5033<p>The type of the incoming values is specified with the first type field. After
5034 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5035 one pair for each predecessor basic block of the current block. Only values
5036 of <a href="#t_firstclass">first class</a> type may be used as the value
5037 arguments to the PHI node. Only labels may be used as the label
5038 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5039
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5040<p>There must be no non-phi instructions between the start of a basic block and
5041 the PHI instructions: i.e. PHI instructions must be first in a basic
5042 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5043
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5044<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5045 occur on the edge from the corresponding predecessor block to the current
5046 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5047 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]5048
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5049<h5>Semantics:</h5>
5050<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5051 specified by the pair corresponding to the predecessor basic block that
5052 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5053
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5054<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5055<pre>
5056Loop: ; Infinite loop that counts from 0 on up...
5057 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5058 %nextindvar = add i32 %indvar, 1
5059 br label %Loop
5060</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5061
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5062</div>
5063
5064<!-- _______________________________________________________________________ -->
5065<div class="doc_subsubsection">
5066 <a name="i_select">'<tt>select</tt>' Instruction</a>
5067</div>
5068
5069<div class="doc_text">
5070
5071<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5072<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]5073 &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>
5074
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5075 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5076</pre>
5077
5078<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5079<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5080 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5081
5082
5083<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5084<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5085 values indicating the condition, and two values of the
5086 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5087 vectors and the condition is a scalar, then entire vectors are selected, not
5088 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5089
5090<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5091<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5092 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5093
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5094<p>If the condition is a vector of i1, then the value arguments must be vectors
5095 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5096
5097<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5098<pre>
5099 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
5100</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5101
5102<p>Note that the code generator does not yet support conditions
5103 with vector type.</p>
5104
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5105</div>
5106
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5107<!-- _______________________________________________________________________ -->
5108<div class="doc_subsubsection">
5109 <a name="i_call">'<tt>call</tt>' Instruction</a>
5110</div>
5111
5112<div class="doc_text">
5113
5114<h5>Syntax:</h5>
5115<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]5116 &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]5117</pre>
5118
5119<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5120<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
5121
5122<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5123<p>This instruction requires several arguments:</p>
5124
5125<ol>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5126 <li>The optional "tail" marker indicates that the callee function does not
5127 access any allocas or varargs in the caller. Note that calls may be
5128 marked "tail" even if they do not occur before
5129 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5130 present, the function call is eligible for tail call optimization,
5131 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
5132 optimized into a jump</a>. As of this writing, the extra requirements for
5133 a call to actually be optimized are:
5134 <ul>
5135 <li>Caller and callee both have the calling
5136 convention <tt>fastcc</tt>.</li>
5137 <li>The call is in tail position (ret immediately follows call and ret
5138 uses value of call or is void).</li>
5139 <li>Option <tt>-tailcallopt</tt> is enabled,
5140 or <code>llvm::PerformTailCallOpt</code> is <code>true</code>.</li>
5141 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5142 constraints are met.</a></li>
5143 </ul>
5144 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5145
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5146 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5147 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5148 defaults to using C calling conventions. The calling convention of the
5149 call must match the calling convention of the target function, or else the
5150 behavior is undefined.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5151
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5152 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5153 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5154 '<tt>inreg</tt>' attributes are valid here.</li>
5155
5156 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5157 type of the return value. Functions that return no value are marked
5158 <tt><a href="#t_void">void</a></tt>.</li>
5159
5160 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5161 being invoked. The argument types must match the types implied by this
5162 signature. This type can be omitted if the function is not varargs and if
5163 the function type does not return a pointer to a function.</li>
5164
5165 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5166 be invoked. In most cases, this is a direct function invocation, but
5167 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5168 to function value.</li>
5169
5170 <li>'<tt>function args</tt>': argument list whose types match the function
5171 signature argument types. All arguments must be of
5172 <a href="#t_firstclass">first class</a> type. If the function signature
5173 indicates the function accepts a variable number of arguments, the extra
5174 arguments can be specified.</li>
5175
5176 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5177 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5178 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5179</ol>
5180
5181<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5182<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5183 a specified function, with its incoming arguments bound to the specified
5184 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5185 function, control flow continues with the instruction after the function
5186 call, and the return value of the function is bound to the result
5187 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5188
5189<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5190<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5191 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5192 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5193 %X = tail call i32 @foo() <i>; yields i32</i>
5194 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5195 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5196
5197 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5198 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5199 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5200 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5201 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5202 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5203</pre>
5204
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5205<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5206standard C99 library as being the C99 library functions, and may perform
5207optimizations or generate code for them under that assumption. This is
5208something we'd like to change in the future to provide better support for
5209freestanding environments and non-C-based langauges.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5211</div>
5212
5213<!-- _______________________________________________________________________ -->
5214<div class="doc_subsubsection">
5215 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5216</div>
5217
5218<div class="doc_text">
5219
5220<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5221<pre>
5222 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5223</pre>
5224
5225<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5226<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5227 the "variable argument" area of a function call. It is used to implement the
5228 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5229
5230<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5231<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5232 argument. It returns a value of the specified argument type and increments
5233 the <tt>va_list</tt> to point to the next argument. The actual type
5234 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5235
5236<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5237<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5238 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5239 to the next argument. For more information, see the variable argument
5240 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5241
5242<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]5243 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5244 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5245
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5246<p><tt>va_arg</tt> is an LLVM instruction instead of
5247 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5248 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5249
5250<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5251<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5252
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5253<p>Note that the code generator does not yet fully support va_arg on many
5254 targets. Also, it does not currently support va_arg with aggregate types on
5255 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5256
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5257</div>
5258
5259<!-- *********************************************************************** -->
5260<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5261<!-- *********************************************************************** -->
5262
5263<div class="doc_text">
5264
5265<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5266 well known names and semantics and are required to follow certain
5267 restrictions. Overall, these intrinsics represent an extension mechanism for
5268 the LLVM language that does not require changing all of the transformations
5269 in LLVM when adding to the language (or the bitcode reader/writer, the
5270 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5271
5272<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5273 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5274 begin with this prefix. Intrinsic functions must always be external
5275 functions: you cannot define the body of intrinsic functions. Intrinsic
5276 functions may only be used in call or invoke instructions: it is illegal to
5277 take the address of an intrinsic function. Additionally, because intrinsic
5278 functions are part of the LLVM language, it is required if any are added that
5279 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5280
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5281<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5282 family of functions that perform the same operation but on different data
5283 types. Because LLVM can represent over 8 million different integer types,
5284 overloading is used commonly to allow an intrinsic function to operate on any
5285 integer type. One or more of the argument types or the result type can be
5286 overloaded to accept any integer type. Argument types may also be defined as
5287 exactly matching a previous argument's type or the result type. This allows
5288 an intrinsic function which accepts multiple arguments, but needs all of them
5289 to be of the same type, to only be overloaded with respect to a single
5290 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5291
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5292<p>Overloaded intrinsics will have the names of its overloaded argument types
5293 encoded into its function name, each preceded by a period. Only those types
5294 which are overloaded result in a name suffix. Arguments whose type is matched
5295 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5296 can take an integer of any width and returns an integer of exactly the same
5297 integer width. This leads to a family of functions such as
5298 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5299 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5300 suffix is required. Because the argument's type is matched against the return
5301 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5302
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5303<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5304 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5305
5306</div>
5307
5308<!-- ======================================================================= -->
5309<div class="doc_subsection">
5310 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5311</div>
5312
5313<div class="doc_text">
5314
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5315<p>Variable argument support is defined in LLVM with
5316 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5317 intrinsic functions. These functions are related to the similarly named
5318 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5319
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5320<p>All of these functions operate on arguments that use a target-specific value
5321 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5322 not define what this type is, so all transformations should be prepared to
5323 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5324
5325<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]5326 instruction and the variable argument handling intrinsic functions are
5327 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5328
5329<div class="doc_code">
5330<pre>
5331define i32 @test(i32 %X, ...) {
5332 ; Initialize variable argument processing
5333 %ap = alloca i8*
5334 %ap2 = bitcast i8** %ap to i8*
5335 call void @llvm.va_start(i8* %ap2)
5336
5337 ; Read a single integer argument
5338 %tmp = va_arg i8** %ap, i32
5339
5340 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5341 %aq = alloca i8*
5342 %aq2 = bitcast i8** %aq to i8*
5343 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5344 call void @llvm.va_end(i8* %aq2)
5345
5346 ; Stop processing of arguments.
5347 call void @llvm.va_end(i8* %ap2)
5348 ret i32 %tmp
5349}
5350
5351declare void @llvm.va_start(i8*)
5352declare void @llvm.va_copy(i8*, i8*)
5353declare void @llvm.va_end(i8*)
5354</pre>
5355</div>
5356
5357</div>
5358
5359<!-- _______________________________________________________________________ -->
5360<div class="doc_subsubsection">
5361 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5362</div>
5363
5364
5365<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5366
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5367<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5368<pre>
5369 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5370</pre>
5371
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5372<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5373<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5374 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]5375
5376<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5377<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]5378
5379<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5380<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]5381 macro available in C. In a target-dependent way, it initializes
5382 the <tt>va_list</tt> element to which the argument points, so that the next
5383 call to <tt>va_arg</tt> will produce the first variable argument passed to
5384 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5385 need to know the last argument of the function as the compiler can figure
5386 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5387
5388</div>
5389
5390<!-- _______________________________________________________________________ -->
5391<div class="doc_subsubsection">
5392 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5393</div>
5394
5395<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5396
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5397<h5>Syntax:</h5>
5398<pre>
5399 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5400</pre>
5401
5402<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5403<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5404 which has been initialized previously
5405 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5406 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5407
5408<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5409<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5410
5411<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5412<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]5413 macro available in C. In a target-dependent way, it destroys
5414 the <tt>va_list</tt> element to which the argument points. Calls
5415 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5416 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5417 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5418
5419</div>
5420
5421<!-- _______________________________________________________________________ -->
5422<div class="doc_subsubsection">
5423 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5424</div>
5425
5426<div class="doc_text">
5427
5428<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5429<pre>
5430 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5431</pre>
5432
5433<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5434<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5435 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5436
5437<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5438<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]5439 The second argument is a pointer to a <tt>va_list</tt> element to copy
5440 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5441
5442<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5443<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]5444 macro available in C. In a target-dependent way, it copies the
5445 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5446 element. This intrinsic is necessary because
5447 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5448 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5449
5450</div>
5451
5452<!-- ======================================================================= -->
5453<div class="doc_subsection">
5454 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5455</div>
5456
5457<div class="doc_text">
5458
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5459<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5460Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5461intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5462roots on the stack</a>, as well as garbage collector implementations that
5463require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5464barriers. Front-ends for type-safe garbage collected languages should generate
5465these intrinsics to make use of the LLVM garbage collectors. For more details,
5466see <a href="GarbageCollection.html">Accurate Garbage Collection with
5467LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5468
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5469<p>The garbage collection intrinsics only operate on objects in the generic
5470 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5471
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5472</div>
5473
5474<!-- _______________________________________________________________________ -->
5475<div class="doc_subsubsection">
5476 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5477</div>
5478
5479<div class="doc_text">
5480
5481<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5482<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5483 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5484</pre>
5485
5486<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5487<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]5488 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5489
5490<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5491<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5492 root pointer. The second pointer (which must be either a constant or a
5493 global value address) contains the meta-data to be associated with the
5494 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5495
5496<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5497<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]5498 location. At compile-time, the code generator generates information to allow
5499 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5500 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5501 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5502
5503</div>
5504
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5505<!-- _______________________________________________________________________ -->
5506<div class="doc_subsubsection">
5507 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5508</div>
5509
5510<div class="doc_text">
5511
5512<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5513<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5514 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5515</pre>
5516
5517<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5518<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5519 locations, allowing garbage collector implementations that require read
5520 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5521
5522<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5523<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]5524 allocated from the garbage collector. The first object is a pointer to the
5525 start of the referenced object, if needed by the language runtime (otherwise
5526 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5527
5528<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5529<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5530 instruction, but may be replaced with substantially more complex code by the
5531 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5532 may only be used in a function which <a href="#gc">specifies a GC
5533 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5534
5535</div>
5536
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5537<!-- _______________________________________________________________________ -->
5538<div class="doc_subsubsection">
5539 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5540</div>
5541
5542<div class="doc_text">
5543
5544<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5545<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5546 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5547</pre>
5548
5549<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5550<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5551 locations, allowing garbage collector implementations that require write
5552 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5553
5554<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5555<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]5556 object to store it to, and the third is the address of the field of Obj to
5557 store to. If the runtime does not require a pointer to the object, Obj may
5558 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5559
5560<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5561<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5562 instruction, but may be replaced with substantially more complex code by the
5563 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5564 may only be used in a function which <a href="#gc">specifies a GC
5565 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5566
5567</div>
5568
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5569<!-- ======================================================================= -->
5570<div class="doc_subsection">
5571 <a name="int_codegen">Code Generator Intrinsics</a>
5572</div>
5573
5574<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5575
5576<p>These intrinsics are provided by LLVM to expose special features that may
5577 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5578
5579</div>
5580
5581<!-- _______________________________________________________________________ -->
5582<div class="doc_subsubsection">
5583 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5584</div>
5585
5586<div class="doc_text">
5587
5588<h5>Syntax:</h5>
5589<pre>
5590 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5591</pre>
5592
5593<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5594<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5595 target-specific value indicating the return address of the current function
5596 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5597
5598<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5599<p>The argument to this intrinsic indicates which function to return the address
5600 for. Zero indicates the calling function, one indicates its caller, etc.
5601 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5602
5603<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5604<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5605 indicating the return address of the specified call frame, or zero if it
5606 cannot be identified. The value returned by this intrinsic is likely to be
5607 incorrect or 0 for arguments other than zero, so it should only be used for
5608 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5609
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5610<p>Note that calling this intrinsic does not prevent function inlining or other
5611 aggressive transformations, so the value returned may not be that of the
5612 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5613
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5614</div>
5615
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5616<!-- _______________________________________________________________________ -->
5617<div class="doc_subsubsection">
5618 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5619</div>
5620
5621<div class="doc_text">
5622
5623<h5>Syntax:</h5>
5624<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5625 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5626</pre>
5627
5628<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5629<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5630 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5631
5632<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5633<p>The argument to this intrinsic indicates which function to return the frame
5634 pointer for. Zero indicates the calling function, one indicates its caller,
5635 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5636
5637<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5638<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5639 indicating the frame address of the specified call frame, or zero if it
5640 cannot be identified. The value returned by this intrinsic is likely to be
5641 incorrect or 0 for arguments other than zero, so it should only be used for
5642 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5643
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5644<p>Note that calling this intrinsic does not prevent function inlining or other
5645 aggressive transformations, so the value returned may not be that of the
5646 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5647
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5648</div>
5649
5650<!-- _______________________________________________________________________ -->
5651<div class="doc_subsubsection">
5652 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5653</div>
5654
5655<div class="doc_text">
5656
5657<h5>Syntax:</h5>
5658<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5659 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5660</pre>
5661
5662<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5663<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5664 of the function stack, for use
5665 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5666 useful for implementing language features like scoped automatic variable
5667 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5668
5669<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5670<p>This intrinsic returns a opaque pointer value that can be passed
5671 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5672 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5673 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5674 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5675 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5676 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5677
5678</div>
5679
5680<!-- _______________________________________________________________________ -->
5681<div class="doc_subsubsection">
5682 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5683</div>
5684
5685<div class="doc_text">
5686
5687<h5>Syntax:</h5>
5688<pre>
5689 declare void @llvm.stackrestore(i8 * %ptr)
5690</pre>
5691
5692<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5693<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5694 the function stack to the state it was in when the
5695 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5696 executed. This is useful for implementing language features like scoped
5697 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5698
5699<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5700<p>See the description
5701 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5702
5703</div>
5704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5705<!-- _______________________________________________________________________ -->
5706<div class="doc_subsubsection">
5707 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5708</div>
5709
5710<div class="doc_text">
5711
5712<h5>Syntax:</h5>
5713<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5714 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]5715</pre>
5716
5717<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5718<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5719 insert a prefetch instruction if supported; otherwise, it is a noop.
5720 Prefetches have no effect on the behavior of the program but can change its
5721 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5722
5723<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5724<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5725 specifier determining if the fetch should be for a read (0) or write (1),
5726 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5727 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5728 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5729
5730<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5731<p>This intrinsic does not modify the behavior of the program. In particular,
5732 prefetches cannot trap and do not produce a value. On targets that support
5733 this intrinsic, the prefetch can provide hints to the processor cache for
5734 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5735
5736</div>
5737
5738<!-- _______________________________________________________________________ -->
5739<div class="doc_subsubsection">
5740 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5741</div>
5742
5743<div class="doc_text">
5744
5745<h5>Syntax:</h5>
5746<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5747 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5748</pre>
5749
5750<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5751<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5752 Counter (PC) in a region of code to simulators and other tools. The method
5753 is target specific, but it is expected that the marker will use exported
5754 symbols to transmit the PC of the marker. The marker makes no guarantees
5755 that it will remain with any specific instruction after optimizations. It is
5756 possible that the presence of a marker will inhibit optimizations. The
5757 intended use is to be inserted after optimizations to allow correlations of
5758 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5759
5760<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5761<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5762
5763<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5764<p>This intrinsic does not modify the behavior of the program. Backends that do
5765 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5766
5767</div>
5768
5769<!-- _______________________________________________________________________ -->
5770<div class="doc_subsubsection">
5771 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5772</div>
5773
5774<div class="doc_text">
5775
5776<h5>Syntax:</h5>
5777<pre>
5778 declare i64 @llvm.readcyclecounter( )
5779</pre>
5780
5781<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5782<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5783 counter register (or similar low latency, high accuracy clocks) on those
5784 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5785 should map to RPCC. As the backing counters overflow quickly (on the order
5786 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5787
5788<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5789<p>When directly supported, reading the cycle counter should not modify any
5790 memory. Implementations are allowed to either return a application specific
5791 value or a system wide value. On backends without support, this is lowered
5792 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5793
5794</div>
5795
5796<!-- ======================================================================= -->
5797<div class="doc_subsection">
5798 <a name="int_libc">Standard C Library Intrinsics</a>
5799</div>
5800
5801<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5802
5803<p>LLVM provides intrinsics for a few important standard C library functions.
5804 These intrinsics allow source-language front-ends to pass information about
5805 the alignment of the pointer arguments to the code generator, providing
5806 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5807
5808</div>
5809
5810<!-- _______________________________________________________________________ -->
5811<div class="doc_subsubsection">
5812 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5813</div>
5814
5815<div class="doc_text">
5816
5817<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5818<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5819 integer bit width. Not all targets support all bit widths however.</p>
5820
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5821<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5822 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5823 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5824 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5825 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5826 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5827 i32 &lt;len&gt;, i32 &lt;align&gt;)
5828 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5829 i64 &lt;len&gt;, i32 &lt;align&gt;)
5830</pre>
5831
5832<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5833<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5834 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5835
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5836<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5837 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5838
5839<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5840<p>The first argument is a pointer to the destination, the second is a pointer
5841 to the source. The third argument is an integer argument specifying the
5842 number of bytes to copy, and the fourth argument is the alignment of the
5843 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5844
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5845<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5846 then the caller guarantees that both the source and destination pointers are
5847 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5848
5849<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5850<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5851 source location to the destination location, which are not allowed to
5852 overlap. It copies "len" bytes of memory over. If the argument is known to
5853 be aligned to some boundary, this can be specified as the fourth argument,
5854 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5855
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5856</div>
5857
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5858<!-- _______________________________________________________________________ -->
5859<div class="doc_subsubsection">
5860 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5861</div>
5862
5863<div class="doc_text">
5864
5865<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5866<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]5867 width. Not all targets support all bit widths however.</p>
5868
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5869<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5870 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5871 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5872 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5873 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5874 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5875 i32 &lt;len&gt;, i32 &lt;align&gt;)
5876 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5877 i64 &lt;len&gt;, i32 &lt;align&gt;)
5878</pre>
5879
5880<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5881<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5882 source location to the destination location. It is similar to the
5883 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5884 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5885
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5886<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5887 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5888
5889<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5890<p>The first argument is a pointer to the destination, the second is a pointer
5891 to the source. The third argument is an integer argument specifying the
5892 number of bytes to copy, and the fourth argument is the alignment of the
5893 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5894
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5895<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5896 then the caller guarantees that the source and destination pointers are
5897 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5898
5899<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5900<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5901 source location to the destination location, which may overlap. It copies
5902 "len" bytes of memory over. If the argument is known to be aligned to some
5903 boundary, this can be specified as the fourth argument, otherwise it should
5904 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5905
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5906</div>
5907
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5908<!-- _______________________________________________________________________ -->
5909<div class="doc_subsubsection">
5910 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5911</div>
5912
5913<div class="doc_text">
5914
5915<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5916<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]5917 width. Not all targets support all bit widths however.</p>
5918
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5919<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5920 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5921 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5922 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5923 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5924 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5925 i32 &lt;len&gt;, i32 &lt;align&gt;)
5926 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5927 i64 &lt;len&gt;, i32 &lt;align&gt;)
5928</pre>
5929
5930<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5931<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5932 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5933
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5934<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5935 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5936
5937<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5938<p>The first argument is a pointer to the destination to fill, the second is the
5939 byte value to fill it with, the third argument is an integer argument
5940 specifying the number of bytes to fill, and the fourth argument is the known
5941 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5942
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5943<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5944 then the caller guarantees that the destination pointer is aligned to that
5945 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5946
5947<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5948<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5949 at the destination location. If the argument is known to be aligned to some
5950 boundary, this can be specified as the fourth argument, otherwise it should
5951 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5952
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5953</div>
5954
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5955<!-- _______________________________________________________________________ -->
5956<div class="doc_subsubsection">
5957 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5958</div>
5959
5960<div class="doc_text">
5961
5962<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5963<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5964 floating point or vector of floating point type. Not all targets support all
5965 types however.</p>
5966
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5967<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5968 declare float @llvm.sqrt.f32(float %Val)
5969 declare double @llvm.sqrt.f64(double %Val)
5970 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5971 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5972 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5973</pre>
5974
5975<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5976<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5977 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5978 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5979 behavior for negative numbers other than -0.0 (which allows for better
5980 optimization, because there is no need to worry about errno being
5981 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]5982
5983<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5984<p>The argument and return value are floating point numbers of the same
5985 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5986
5987<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5988<p>This function returns the sqrt of the specified operand if it is a
5989 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5990
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5991</div>
5992
5993<!-- _______________________________________________________________________ -->
5994<div class="doc_subsubsection">
5995 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5996</div>
5997
5998<div class="doc_text">
5999
6000<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6001<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6002 floating point or vector of floating point type. Not all targets support all
6003 types however.</p>
6004
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6005<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]6006 declare float @llvm.powi.f32(float %Val, i32 %power)
6007 declare double @llvm.powi.f64(double %Val, i32 %power)
6008 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6009 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6010 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6011</pre>
6012
6013<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6014<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6015 specified (positive or negative) power. The order of evaluation of
6016 multiplications is not defined. When a vector of floating point type is
6017 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6018
6019<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6020<p>The second argument is an integer power, and the first is a value to raise to
6021 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6022
6023<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6024<p>This function returns the first value raised to the second power with an
6025 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6026
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6027</div>
6028
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6029<!-- _______________________________________________________________________ -->
6030<div class="doc_subsubsection">
6031 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6032</div>
6033
6034<div class="doc_text">
6035
6036<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6037<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6038 floating point or vector of floating point type. Not all targets support all
6039 types however.</p>
6040
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6041<pre>
6042 declare float @llvm.sin.f32(float %Val)
6043 declare double @llvm.sin.f64(double %Val)
6044 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6045 declare fp128 @llvm.sin.f128(fp128 %Val)
6046 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6047</pre>
6048
6049<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6050<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6051
6052<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6053<p>The argument and return value are floating point numbers of the same
6054 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6055
6056<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6057<p>This function returns the sine of the specified operand, returning the same
6058 values as the libm <tt>sin</tt> functions would, and handles error conditions
6059 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6060
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6061</div>
6062
6063<!-- _______________________________________________________________________ -->
6064<div class="doc_subsubsection">
6065 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6066</div>
6067
6068<div class="doc_text">
6069
6070<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6071<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6072 floating point or vector of floating point type. Not all targets support all
6073 types however.</p>
6074
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6075<pre>
6076 declare float @llvm.cos.f32(float %Val)
6077 declare double @llvm.cos.f64(double %Val)
6078 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6079 declare fp128 @llvm.cos.f128(fp128 %Val)
6080 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6081</pre>
6082
6083<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6084<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6085
6086<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6087<p>The argument and return value are floating point numbers of the same
6088 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6089
6090<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6091<p>This function returns the cosine of the specified operand, returning the same
6092 values as the libm <tt>cos</tt> functions would, and handles error conditions
6093 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6094
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6095</div>
6096
6097<!-- _______________________________________________________________________ -->
6098<div class="doc_subsubsection">
6099 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6100</div>
6101
6102<div class="doc_text">
6103
6104<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6105<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6106 floating point or vector of floating point type. Not all targets support all
6107 types however.</p>
6108
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6109<pre>
6110 declare float @llvm.pow.f32(float %Val, float %Power)
6111 declare double @llvm.pow.f64(double %Val, double %Power)
6112 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6113 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6114 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6115</pre>
6116
6117<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6118<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6119 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6120
6121<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6122<p>The second argument is a floating point power, and the first is a value to
6123 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6124
6125<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6126<p>This function returns the first value raised to the second power, returning
6127 the same values as the libm <tt>pow</tt> functions would, and handles error
6128 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6129
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6130</div>
6131
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6132<!-- ======================================================================= -->
6133<div class="doc_subsection">
6134 <a name="int_manip">Bit Manipulation Intrinsics</a>
6135</div>
6136
6137<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6138
6139<p>LLVM provides intrinsics for a few important bit manipulation operations.
6140 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6141
6142</div>
6143
6144<!-- _______________________________________________________________________ -->
6145<div class="doc_subsubsection">
6146 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
6147</div>
6148
6149<div class="doc_text">
6150
6151<h5>Syntax:</h5>
6152<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6153 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6154
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6155<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6156 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6157 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6158 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6159</pre>
6160
6161<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6162<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6163 values with an even number of bytes (positive multiple of 16 bits). These
6164 are useful for performing operations on data that is not in the target's
6165 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6166
6167<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6168<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6169 and low byte of the input i16 swapped. Similarly,
6170 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6171 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6172 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6173 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6174 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6175 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6176
6177</div>
6178
6179<!-- _______________________________________________________________________ -->
6180<div class="doc_subsubsection">
6181 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6182</div>
6183
6184<div class="doc_text">
6185
6186<h5>Syntax:</h5>
6187<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]6188 width. Not all targets support all bit widths however.</p>
6189
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6190<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6191 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6192 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6193 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6194 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6195 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6196</pre>
6197
6198<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6199<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6200 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6201
6202<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6203<p>The only argument is the value to be counted. The argument may be of any
6204 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6205
6206<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6207<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]6208
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6209</div>
6210
6211<!-- _______________________________________________________________________ -->
6212<div class="doc_subsubsection">
6213 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6214</div>
6215
6216<div class="doc_text">
6217
6218<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6219<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6220 integer bit width. Not all targets support all bit widths however.</p>
6221
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6222<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6223 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6224 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6225 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6226 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6227 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6228</pre>
6229
6230<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6231<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6232 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6233
6234<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6235<p>The only argument is the value to be counted. The argument may be of any
6236 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6237
6238<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6239<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6240 zeros in a variable. If the src == 0 then the result is the size in bits of
6241 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6242
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6243</div>
6244
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6245<!-- _______________________________________________________________________ -->
6246<div class="doc_subsubsection">
6247 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6248</div>
6249
6250<div class="doc_text">
6251
6252<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6253<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6254 integer bit width. Not all targets support all bit widths however.</p>
6255
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6256<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6257 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6258 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6259 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6260 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6261 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6262</pre>
6263
6264<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6265<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6266 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6267
6268<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6269<p>The only argument is the value to be counted. The argument may be of any
6270 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6271
6272<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6273<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6274 zeros in a variable. If the src == 0 then the result is the size in bits of
6275 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6276
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6277</div>
6278
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6279<!-- ======================================================================= -->
6280<div class="doc_subsection">
6281 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6282</div>
6283
6284<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6285
6286<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6287
6288</div>
6289
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6290<!-- _______________________________________________________________________ -->
6291<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6292 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6293</div>
6294
6295<div class="doc_text">
6296
6297<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6298<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]6299 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6300
6301<pre>
6302 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6303 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6304 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6305</pre>
6306
6307<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6308<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6309 a signed addition of the two arguments, and indicate whether an overflow
6310 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6311
6312<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6313<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]6314 be of integer types of any bit width, but they must have the same bit
6315 width. The second element of the result structure must be of
6316 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6317 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6318
6319<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6320<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6321 a signed addition of the two variables. They return a structure &mdash; the
6322 first element of which is the signed summation, and the second element of
6323 which is a bit specifying if the signed summation resulted in an
6324 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6325
6326<h5>Examples:</h5>
6327<pre>
6328 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6329 %sum = extractvalue {i32, i1} %res, 0
6330 %obit = extractvalue {i32, i1} %res, 1
6331 br i1 %obit, label %overflow, label %normal
6332</pre>
6333
6334</div>
6335
6336<!-- _______________________________________________________________________ -->
6337<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6338 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6339</div>
6340
6341<div class="doc_text">
6342
6343<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6344<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]6345 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6346
6347<pre>
6348 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6349 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6350 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6351</pre>
6352
6353<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6354<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6355 an unsigned addition of the two arguments, and indicate whether a carry
6356 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6357
6358<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6359<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]6360 be of integer types of any bit width, but they must have the same bit
6361 width. The second element of the result structure must be of
6362 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6363 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6364
6365<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6366<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6367 an unsigned addition of the two arguments. They return a structure &mdash;
6368 the first element of which is the sum, and the second element of which is a
6369 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6370
6371<h5>Examples:</h5>
6372<pre>
6373 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6374 %sum = extractvalue {i32, i1} %res, 0
6375 %obit = extractvalue {i32, i1} %res, 1
6376 br i1 %obit, label %carry, label %normal
6377</pre>
6378
6379</div>
6380
6381<!-- _______________________________________________________________________ -->
6382<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6383 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6384</div>
6385
6386<div class="doc_text">
6387
6388<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6389<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]6390 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6391
6392<pre>
6393 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6394 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6395 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6396</pre>
6397
6398<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6399<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6400 a signed subtraction of the two arguments, and indicate whether an overflow
6401 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6402
6403<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6404<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]6405 be of integer types of any bit width, but they must have the same bit
6406 width. The second element of the result structure must be of
6407 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6408 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6409
6410<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6411<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6412 a signed subtraction of the two arguments. They return a structure &mdash;
6413 the first element of which is the subtraction, and the second element of
6414 which is a bit specifying if the signed subtraction resulted in an
6415 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6416
6417<h5>Examples:</h5>
6418<pre>
6419 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6420 %sum = extractvalue {i32, i1} %res, 0
6421 %obit = extractvalue {i32, i1} %res, 1
6422 br i1 %obit, label %overflow, label %normal
6423</pre>
6424
6425</div>
6426
6427<!-- _______________________________________________________________________ -->
6428<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6429 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6430</div>
6431
6432<div class="doc_text">
6433
6434<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6435<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]6436 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6437
6438<pre>
6439 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6440 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6441 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6442</pre>
6443
6444<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6445<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6446 an unsigned subtraction of the two arguments, and indicate whether an
6447 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6448
6449<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6450<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]6451 be of integer types of any bit width, but they must have the same bit
6452 width. The second element of the result structure must be of
6453 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6454 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6455
6456<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6457<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6458 an unsigned subtraction of the two arguments. They return a structure &mdash;
6459 the first element of which is the subtraction, and the second element of
6460 which is a bit specifying if the unsigned subtraction resulted in an
6461 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6462
6463<h5>Examples:</h5>
6464<pre>
6465 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6466 %sum = extractvalue {i32, i1} %res, 0
6467 %obit = extractvalue {i32, i1} %res, 1
6468 br i1 %obit, label %overflow, label %normal
6469</pre>
6470
6471</div>
6472
6473<!-- _______________________________________________________________________ -->
6474<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6475 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6476</div>
6477
6478<div class="doc_text">
6479
6480<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6481<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]6482 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6483
6484<pre>
6485 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6486 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6487 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6488</pre>
6489
6490<h5>Overview:</h5>
6491
6492<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6493 a signed multiplication of the two arguments, and indicate whether an
6494 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6495
6496<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6497<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]6498 be of integer types of any bit width, but they must have the same bit
6499 width. The second element of the result structure must be of
6500 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6501 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6502
6503<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6504<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6505 a signed multiplication of the two arguments. They return a structure &mdash;
6506 the first element of which is the multiplication, and the second element of
6507 which is a bit specifying if the signed multiplication resulted in an
6508 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6509
6510<h5>Examples:</h5>
6511<pre>
6512 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6513 %sum = extractvalue {i32, i1} %res, 0
6514 %obit = extractvalue {i32, i1} %res, 1
6515 br i1 %obit, label %overflow, label %normal
6516</pre>
6517
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6518</div>
6519
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6520<!-- _______________________________________________________________________ -->
6521<div class="doc_subsubsection">
6522 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6523</div>
6524
6525<div class="doc_text">
6526
6527<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6528<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]6529 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6530
6531<pre>
6532 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6533 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6534 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6535</pre>
6536
6537<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6538<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6539 a unsigned multiplication of the two arguments, and indicate whether an
6540 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6541
6542<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6543<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]6544 be of integer types of any bit width, but they must have the same bit
6545 width. The second element of the result structure must be of
6546 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6547 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6548
6549<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6550<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6551 an unsigned multiplication of the two arguments. They return a structure
6552 &mdash; the first element of which is the multiplication, and the second
6553 element of which is a bit specifying if the unsigned multiplication resulted
6554 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6555
6556<h5>Examples:</h5>
6557<pre>
6558 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6559 %sum = extractvalue {i32, i1} %res, 0
6560 %obit = extractvalue {i32, i1} %res, 1
6561 br i1 %obit, label %overflow, label %normal
6562</pre>
6563
6564</div>
6565
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6566<!-- ======================================================================= -->
6567<div class="doc_subsection">
6568 <a name="int_debugger">Debugger Intrinsics</a>
6569</div>
6570
6571<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6572
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6573<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6574 prefix), are described in
6575 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6576 Level Debugging</a> document.</p>
6577
6578</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6579
6580<!-- ======================================================================= -->
6581<div class="doc_subsection">
6582 <a name="int_eh">Exception Handling Intrinsics</a>
6583</div>
6584
6585<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6586
6587<p>The LLVM exception handling intrinsics (which all start with
6588 <tt>llvm.eh.</tt> prefix), are described in
6589 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6590 Handling</a> document.</p>
6591
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6592</div>
6593
6594<!-- ======================================================================= -->
6595<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6596 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6597</div>
6598
6599<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6600
6601<p>This intrinsic makes it possible to excise one parameter, marked with
6602 the <tt>nest</tt> attribute, from a function. The result is a callable
6603 function pointer lacking the nest parameter - the caller does not need to
6604 provide a value for it. Instead, the value to use is stored in advance in a
6605 "trampoline", a block of memory usually allocated on the stack, which also
6606 contains code to splice the nest value into the argument list. This is used
6607 to implement the GCC nested function address extension.</p>
6608
6609<p>For example, if the function is
6610 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6611 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6612 follows:</p>
6613
6614<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6615<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6616 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6617 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6618 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6619 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6620</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6621</div>
6622
6623<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6624 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6625
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6626</div>
6627
6628<!-- _______________________________________________________________________ -->
6629<div class="doc_subsubsection">
6630 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6631</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6632
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6633<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6634
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6635<h5>Syntax:</h5>
6636<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6637 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]6638</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6639
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6640<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6641<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6642 function pointer suitable for executing it.</p>
6643
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6644<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6645<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6646 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6647 sufficiently aligned block of memory; this memory is written to by the
6648 intrinsic. Note that the size and the alignment are target-specific - LLVM
6649 currently provides no portable way of determining them, so a front-end that
6650 generates this intrinsic needs to have some target-specific knowledge.
6651 The <tt>func</tt> argument must hold a function bitcast to
6652 an <tt>i8*</tt>.</p>
6653
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6654<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6655<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6656 dependent code, turning it into a function. A pointer to this function is
6657 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6658 function pointer type</a> before being called. The new function's signature
6659 is the same as that of <tt>func</tt> with any arguments marked with
6660 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6661 is allowed, and it must be of pointer type. Calling the new function is
6662 equivalent to calling <tt>func</tt> with the same argument list, but
6663 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6664 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6665 by <tt>tramp</tt> is modified, then the effect of any later call to the
6666 returned function pointer is undefined.</p>
6667
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6668</div>
6669
6670<!-- ======================================================================= -->
6671<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6672 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6673</div>
6674
6675<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6676
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6677<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6678 hardware constructs for atomic operations and memory synchronization. This
6679 provides an interface to the hardware, not an interface to the programmer. It
6680 is aimed at a low enough level to allow any programming models or APIs
6681 (Application Programming Interfaces) which need atomic behaviors to map
6682 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6683 hardware provides a "universal IR" for source languages, it also provides a
6684 starting point for developing a "universal" atomic operation and
6685 synchronization IR.</p>
6686
6687<p>These do <em>not</em> form an API such as high-level threading libraries,
6688 software transaction memory systems, atomic primitives, and intrinsic
6689 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6690 application libraries. The hardware interface provided by LLVM should allow
6691 a clean implementation of all of these APIs and parallel programming models.
6692 No one model or paradigm should be selected above others unless the hardware
6693 itself ubiquitously does so.</p>
6694
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6695</div>
6696
6697<!-- _______________________________________________________________________ -->
6698<div class="doc_subsubsection">
6699 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6700</div>
6701<div class="doc_text">
6702<h5>Syntax:</h5>
6703<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6704 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]6705</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6706
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6707<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6708<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6709 specific pairs of memory access types.</p>
6710
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6711<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6712<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6713 The first four arguments enables a specific barrier as listed below. The
6714 fith argument specifies that the barrier applies to io or device or uncached
6715 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6716
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6717<ul>
6718 <li><tt>ll</tt>: load-load barrier</li>
6719 <li><tt>ls</tt>: load-store barrier</li>
6720 <li><tt>sl</tt>: store-load barrier</li>
6721 <li><tt>ss</tt>: store-store barrier</li>
6722 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6723</ul>
6724
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6725<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6726<p>This intrinsic causes the system to enforce some ordering constraints upon
6727 the loads and stores of the program. This barrier does not
6728 indicate <em>when</em> any events will occur, it only enforces
6729 an <em>order</em> in which they occur. For any of the specified pairs of load
6730 and store operations (f.ex. load-load, or store-load), all of the first
6731 operations preceding the barrier will complete before any of the second
6732 operations succeeding the barrier begin. Specifically the semantics for each
6733 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6734
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6735<ul>
6736 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6737 after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6738 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6739 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6740 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6741 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6742 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6743 load after the barrier begins.</li>
6744</ul>
6745
6746<p>These semantics are applied with a logical "and" behavior when more than one
6747 is enabled in a single memory barrier intrinsic.</p>
6748
6749<p>Backends may implement stronger barriers than those requested when they do
6750 not support as fine grained a barrier as requested. Some architectures do
6751 not need all types of barriers and on such architectures, these become
6752 noops.</p>
6753
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6754<h5>Example:</h5>
6755<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6756%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6757%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6758 store i32 4, %ptr
6759
6760%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6761 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6762 <i>; guarantee the above finishes</i>
6763 store i32 8, %ptr <i>; before this begins</i>
6764</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6765
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6766</div>
6767
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6768<!-- _______________________________________________________________________ -->
6769<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6770 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6771</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6772
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6773<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6774
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6775<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6776<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6777 any integer bit width and for different address spaces. Not all targets
6778 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6779
6780<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6781 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6782 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6783 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6784 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]6785</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6786
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6787<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6788<p>This loads a value in memory and compares it to a given value. If they are
6789 equal, it stores a new value into the memory.</p>
6790
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6791<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6792<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6793 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6794 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6795 this integer type. While any bit width integer may be used, targets may only
6796 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6797
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6798<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6799<p>This entire intrinsic must be executed atomically. It first loads the value
6800 in memory pointed to by <tt>ptr</tt> and compares it with the
6801 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6802 memory. The loaded value is yielded in all cases. This provides the
6803 equivalent of an atomic compare-and-swap operation within the SSA
6804 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6805
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6806<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6807<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6808%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6809%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6810 store i32 4, %ptr
6811
6812%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6813%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6814 <i>; yields {i32}:result1 = 4</i>
6815%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6816%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6817
6818%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6819%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6820 <i>; yields {i32}:result2 = 8</i>
6821%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6822
6823%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6824</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6825
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6826</div>
6827
6828<!-- _______________________________________________________________________ -->
6829<div class="doc_subsubsection">
6830 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6831</div>
6832<div class="doc_text">
6833<h5>Syntax:</h5>
6834
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6835<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6836 integer bit width. Not all targets support all bit widths however.</p>
6837
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6838<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6839 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6840 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6841 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6842 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]6843</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6844
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6845<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6846<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6847 the value from memory. It then stores the value in <tt>val</tt> in the memory
6848 at <tt>ptr</tt>.</p>
6849
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6850<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6851<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6852 the <tt>val</tt> argument and the result must be integers of the same bit
6853 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6854 integer type. The targets may only lower integer representations they
6855 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6856
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6857<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6858<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6859 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6860 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6861
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6862<h5>Examples:</h5>
6863<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6864%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6865%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6866 store i32 4, %ptr
6867
6868%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6869%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6870 <i>; yields {i32}:result1 = 4</i>
6871%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6872%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6873
6874%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6875%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6876 <i>; yields {i32}:result2 = 8</i>
6877
6878%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6879%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6880</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6881
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6882</div>
6883
6884<!-- _______________________________________________________________________ -->
6885<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6886 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6887
6888</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6889
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6890<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6891
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6892<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6893<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6894 any integer bit width. Not all targets support all bit widths however.</p>
6895
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6896<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6897 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6898 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6899 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6900 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]6901</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6902
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6903<h5>Overview:</h5>
6904<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6905 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6906
6907<h5>Arguments:</h5>
6908<p>The intrinsic takes two arguments, the first a pointer to an integer value
6909 and the second an integer value. The result is also an integer value. These
6910 integer types can have any bit width, but they must all have the same bit
6911 width. The targets may only lower integer representations they support.</p>
6912
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6913<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6914<p>This intrinsic does a series of operations atomically. It first loads the
6915 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6916 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]6917
6918<h5>Examples:</h5>
6919<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6920%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6921%ptr = bitcast i8* %mallocP to i32*
6922 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6923%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6924 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6925%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6926 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6927%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6928 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6929%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6930</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6931
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6932</div>
6933
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6934<!-- _______________________________________________________________________ -->
6935<div class="doc_subsubsection">
6936 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6937
6938</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6939
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6940<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6941
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6942<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6943<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6944 any integer bit width and for different address spaces. Not all targets
6945 support all bit widths however.</p>
6946
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6947<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6948 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6949 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6950 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6951 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]6952</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6953
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6954<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6955<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6956 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6957
6958<h5>Arguments:</h5>
6959<p>The intrinsic takes two arguments, the first a pointer to an integer value
6960 and the second an integer value. The result is also an integer value. These
6961 integer types can have any bit width, but they must all have the same bit
6962 width. The targets may only lower integer representations they support.</p>
6963
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6964<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6965<p>This intrinsic does a series of operations atomically. It first loads the
6966 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6967 result to <tt>ptr</tt>. It yields the original value stored
6968 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6969
6970<h5>Examples:</h5>
6971<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6972%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6973%ptr = bitcast i8* %mallocP to i32*
6974 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6975%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6976 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6977%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6978 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6979%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6980 <i>; yields {i32}:result3 = 2</i>
6981%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6982</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6983
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6984</div>
6985
6986<!-- _______________________________________________________________________ -->
6987<div class="doc_subsubsection">
6988 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6989 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6990 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6991 <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]6992</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6993
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6994<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6995
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6996<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6997<p>These are overloaded intrinsics. You can
6998 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6999 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7000 bit width and for different address spaces. Not all targets support all bit
7001 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7002
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7003<pre>
7004 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7005 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7006 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7007 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]7008</pre>
7009
7010<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7011 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7012 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7013 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7014 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]7015</pre>
7016
7017<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7018 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7019 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7020 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7021 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]7022</pre>
7023
7024<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7025 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7026 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7027 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7028 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]7029</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7030
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7031<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7032<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7033 the value stored in memory at <tt>ptr</tt>. It yields the original value
7034 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7035
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7036<h5>Arguments:</h5>
7037<p>These intrinsics take two arguments, the first a pointer to an integer value
7038 and the second an integer value. The result is also an integer value. These
7039 integer types can have any bit width, but they must all have the same bit
7040 width. The targets may only lower integer representations they support.</p>
7041
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7042<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7043<p>These intrinsics does a series of operations atomically. They first load the
7044 value stored at <tt>ptr</tt>. They then do the bitwise
7045 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7046 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7047
7048<h5>Examples:</h5>
7049<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7050%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7051%ptr = bitcast i8* %mallocP to i32*
7052 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7053%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7054 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7055%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7056 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7057%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7058 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7059%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7060 <i>; yields {i32}:result3 = FF</i>
7061%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7062</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7063
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7064</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7065
7066<!-- _______________________________________________________________________ -->
7067<div class="doc_subsubsection">
7068 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7069 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7070 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7071 <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]7072</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7073
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7074<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7075
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7076<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7077<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7078 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7079 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7080 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7081
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7082<pre>
7083 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7084 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7085 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7086 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]7087</pre>
7088
7089<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7090 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7091 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7092 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7093 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]7094</pre>
7095
7096<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7097 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7098 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7099 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7100 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]7101</pre>
7102
7103<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7104 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7105 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7106 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7107 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]7108</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7109
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7110<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7111<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7112 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7113 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7114
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7115<h5>Arguments:</h5>
7116<p>These intrinsics take two arguments, the first a pointer to an integer value
7117 and the second an integer value. The result is also an integer value. These
7118 integer types can have any bit width, but they must all have the same bit
7119 width. The targets may only lower integer representations they support.</p>
7120
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7121<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7122<p>These intrinsics does a series of operations atomically. They first load the
7123 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7124 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7125 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7126
7127<h5>Examples:</h5>
7128<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7129%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7130%ptr = bitcast i8* %mallocP to i32*
7131 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7132%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7133 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7134%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7135 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7136%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7137 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7138%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7139 <i>; yields {i32}:result3 = 8</i>
7140%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7141</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7142
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7143</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7144
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7145
7146<!-- ======================================================================= -->
7147<div class="doc_subsection">
7148 <a name="int_memorymarkers">Memory Use Markers</a>
7149</div>
7150
7151<div class="doc_text">
7152
7153<p>This class of intrinsics exists to information about the lifetime of memory
7154 objects and ranges where variables are immutable.</p>
7155
7156</div>
7157
7158<!-- _______________________________________________________________________ -->
7159<div class="doc_subsubsection">
7160 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7161</div>
7162
7163<div class="doc_text">
7164
7165<h5>Syntax:</h5>
7166<pre>
7167 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7168</pre>
7169
7170<h5>Overview:</h5>
7171<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7172 object's lifetime.</p>
7173
7174<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7175<p>The first argument is a constant integer representing the size of the
7176 object, or -1 if it is variable sized. The second argument is a pointer to
7177 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7178
7179<h5>Semantics:</h5>
7180<p>This intrinsic indicates that before this point in the code, the value of the
7181 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]7182 never be used and has an undefined value. A load from the pointer that
7183 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7184 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7185
7186</div>
7187
7188<!-- _______________________________________________________________________ -->
7189<div class="doc_subsubsection">
7190 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7191</div>
7192
7193<div class="doc_text">
7194
7195<h5>Syntax:</h5>
7196<pre>
7197 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7198</pre>
7199
7200<h5>Overview:</h5>
7201<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7202 object's lifetime.</p>
7203
7204<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7205<p>The first argument is a constant integer representing the size of the
7206 object, or -1 if it is variable sized. The second argument is a pointer to
7207 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7208
7209<h5>Semantics:</h5>
7210<p>This intrinsic indicates that after this point in the code, the value of the
7211 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7212 never be used and has an undefined value. Any stores into the memory object
7213 following this intrinsic may be removed as dead.
7214
7215</div>
7216
7217<!-- _______________________________________________________________________ -->
7218<div class="doc_subsubsection">
7219 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7220</div>
7221
7222<div class="doc_text">
7223
7224<h5>Syntax:</h5>
7225<pre>
7226 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7227</pre>
7228
7229<h5>Overview:</h5>
7230<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7231 a memory object will not change.</p>
7232
7233<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7234<p>The first argument is a constant integer representing the size of the
7235 object, or -1 if it is variable sized. The second argument is a pointer to
7236 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7237
7238<h5>Semantics:</h5>
7239<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7240 the return value, the referenced memory location is constant and
7241 unchanging.</p>
7242
7243</div>
7244
7245<!-- _______________________________________________________________________ -->
7246<div class="doc_subsubsection">
7247 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7248</div>
7249
7250<div class="doc_text">
7251
7252<h5>Syntax:</h5>
7253<pre>
7254 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7255</pre>
7256
7257<h5>Overview:</h5>
7258<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7259 a memory object are mutable.</p>
7260
7261<h5>Arguments:</h5>
7262<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7263 The second argument is a constant integer representing the size of the
7264 object, or -1 if it is variable sized and the third argument is a pointer
7265 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7266
7267<h5>Semantics:</h5>
7268<p>This intrinsic indicates that the memory is mutable again.</p>
7269
7270</div>
7271
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7272<!-- ======================================================================= -->
7273<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7274 <a name="int_general">General Intrinsics</a>
7275</div>
7276
7277<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7278
7279<p>This class of intrinsics is designed to be generic and has no specific
7280 purpose.</p>
7281
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7282</div>
7283
7284<!-- _______________________________________________________________________ -->
7285<div class="doc_subsubsection">
7286 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7287</div>
7288
7289<div class="doc_text">
7290
7291<h5>Syntax:</h5>
7292<pre>
7293 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7294</pre>
7295
7296<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7297<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7298
7299<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7300<p>The first argument is a pointer to a value, the second is a pointer to a
7301 global string, the third is a pointer to a global string which is the source
7302 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7303
7304<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7305<p>This intrinsic allows annotation of local variables with arbitrary strings.
7306 This can be useful for special purpose optimizations that want to look for
7307 these annotations. These have no other defined use, they are ignored by code
7308 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7309
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7310</div>
7311
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7312<!-- _______________________________________________________________________ -->
7313<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7314 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7315</div>
7316
7317<div class="doc_text">
7318
7319<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7320<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7321 any integer bit width.</p>
7322
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7323<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7324 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7325 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7326 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7327 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7328 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]7329</pre>
7330
7331<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7332<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7333
7334<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7335<p>The first argument is an integer value (result of some expression), the
7336 second is a pointer to a global string, the third is a pointer to a global
7337 string which is the source file name, and the last argument is the line
7338 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7339
7340<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7341<p>This intrinsic allows annotations to be put on arbitrary expressions with
7342 arbitrary strings. This can be useful for special purpose optimizations that
7343 want to look for these annotations. These have no other defined use, they
7344 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7345
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7346</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7347
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7348<!-- _______________________________________________________________________ -->
7349<div class="doc_subsubsection">
7350 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7351</div>
7352
7353<div class="doc_text">
7354
7355<h5>Syntax:</h5>
7356<pre>
7357 declare void @llvm.trap()
7358</pre>
7359
7360<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7361<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7362
7363<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7364<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7365
7366<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7367<p>This intrinsics is lowered to the target dependent trap instruction. If the
7368 target does not have a trap instruction, this intrinsic will be lowered to
7369 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7370
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7371</div>
7372
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7373<!-- _______________________________________________________________________ -->
7374<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7375 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7376</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7377
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7378<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7379
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7380<h5>Syntax:</h5>
7381<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7382 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7383</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7384
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7385<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7386<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7387 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7388 ensure that it is placed on the stack before local variables.</p>
7389
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7390<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7391<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7392 arguments. The first argument is the value loaded from the stack
7393 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7394 that has enough space to hold the value of the guard.</p>
7395
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7396<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7397<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7398 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7399 stack. This is to ensure that if a local variable on the stack is
7400 overwritten, it will destroy the value of the guard. When the function exits,
7401 the guard on the stack is checked against the original guard. If they're
7402 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7403 function.</p>
7404
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7405</div>
7406
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7407<!-- _______________________________________________________________________ -->
7408<div class="doc_subsubsection">
7409 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7410</div>
7411
7412<div class="doc_text">
7413
7414<h5>Syntax:</h5>
7415<pre>
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7416 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7417 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7418</pre>
7419
7420<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7421<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher184f44d2010-01-08 21:42:39 +0000[diff] [blame]7422 to the optimizers to discover at compile time either a) when an
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7423 operation like memcpy will either overflow a buffer that corresponds to
7424 an object, or b) to determine that a runtime check for overflow isn't
7425 necessary. An object in this context means an allocation of a
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7426 specific class, structure, array, or other object.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7427
7428<h5>Arguments:</h5>
7429<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7430 argument is a pointer to or into the <tt>object</tt>. The second argument
7431 is a boolean 0 or 1. This argument determines whether you want the
7432 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7433 1, variables are not allowed.</p>
7434
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7435<h5>Semantics:</h5>
7436<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7437 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7438 (depending on the <tt>type</tt> argument if the size cannot be determined
7439 at compile time.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7440
7441</div>
7442
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7443<!-- *********************************************************************** -->
7444<hr>
7445<address>
7446 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7447 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7448 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7449 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]7450
7451 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7452 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7453 Last modified: $Date$
7454</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7455
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7456</body>
7457</html>