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5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
27 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
28 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
29 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
30 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
31 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
32 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
33 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner0fee5c22009-10-10 18:26:06 +0000[diff] [blame]34 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]35 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
36 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
37 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]39 </ol>
40 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]41 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]42 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]43 <li><a href="#globalvars">Global Variables</a></li>
44 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]45 <li><a href="#aliasstructure">Aliases</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]46 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]47 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]48 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]49 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
50 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]51 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]52 </ol>
53 </li>
54 <li><a href="#typesystem">Type System</a>
55 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]56 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]57 <li><a href="#t_primitive">Primitive Types</a>
58 <ol>
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]59 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_floating">Floating Point Types</a></li>
61 <li><a href="#t_void">Void Type</a></li>
62 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]63 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]64 </ol>
65 </li>
66 <li><a href="#t_derived">Derived Types</a>
67 <ol>
68 <li><a href="#t_array">Array Type</a></li>
69 <li><a href="#t_function">Function Type</a></li>
70 <li><a href="#t_pointer">Pointer Type</a></li>
71 <li><a href="#t_struct">Structure Type</a></li>
72 <li><a href="#t_pstruct">Packed Structure Type</a></li>
73 <li><a href="#t_vector">Vector Type</a></li>
74 <li><a href="#t_opaque">Opaque Type</a></li>
75 </ol>
76 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]77 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]78 </ol>
79 </li>
80 <li><a href="#constants">Constants</a>
81 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]82 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]83 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]84 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
85 <li><a href="#undefvalues">Undefined Values</a></li>
86 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]87 <li><a href="#metadata">Embedded Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]88 </ol>
89 </li>
90 <li><a href="#othervalues">Other Values</a>
91 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]92 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]93 </ol>
94 </li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]95 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
96 <ol>
97 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]98 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
99 Global Variable</a></li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]100 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
101 Global Variable</a></li>
102 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
103 Global Variable</a></li>
104 </ol>
105 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]106 <li><a href="#instref">Instruction Reference</a>
107 <ol>
108 <li><a href="#terminators">Terminator Instructions</a>
109 <ol>
110 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
111 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
112 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
113 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
114 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
115 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
116 </ol>
117 </li>
118 <li><a href="#binaryops">Binary Operations</a>
119 <ol>
120 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]121 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]122 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]123 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]124 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]125 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]126 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
127 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
128 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
129 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
130 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
131 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
132 </ol>
133 </li>
134 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
135 <ol>
136 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
137 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
138 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
139 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
140 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
141 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
142 </ol>
143 </li>
144 <li><a href="#vectorops">Vector Operations</a>
145 <ol>
146 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
147 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
148 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
149 </ol>
150 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]151 <li><a href="#aggregateops">Aggregate Operations</a>
152 <ol>
153 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
154 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
155 </ol>
156 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]157 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
158 <ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]159 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
160 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
161 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
162 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
163 </ol>
164 </li>
165 <li><a href="#convertops">Conversion Operations</a>
166 <ol>
167 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
168 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
169 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
170 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
171 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
172 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
173 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
174 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
175 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
176 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
177 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
178 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
179 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]180 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]181 <li><a href="#otherops">Other Operations</a>
182 <ol>
183 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
184 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
185 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
186 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
187 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
188 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
189 </ol>
190 </li>
191 </ol>
192 </li>
193 <li><a href="#intrinsics">Intrinsic Functions</a>
194 <ol>
195 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
196 <ol>
197 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
198 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
199 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
200 </ol>
201 </li>
202 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
203 <ol>
204 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
205 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
206 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
207 </ol>
208 </li>
209 <li><a href="#int_codegen">Code Generator Intrinsics</a>
210 <ol>
211 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
212 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
213 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
214 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
215 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
216 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
217 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
218 </ol>
219 </li>
220 <li><a href="#int_libc">Standard C Library Intrinsics</a>
221 <ol>
222 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
223 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
224 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
225 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
226 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]227 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
228 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
229 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]230 </ol>
231 </li>
232 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
233 <ol>
234 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
235 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
236 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
237 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]238 </ol>
239 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]240 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
241 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]242 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
243 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
244 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
245 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
246 <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]247 <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]248 </ol>
249 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]250 <li><a href="#int_debugger">Debugger intrinsics</a></li>
251 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]252 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]253 <ol>
254 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]255 </ol>
256 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]257 <li><a href="#int_atomics">Atomic intrinsics</a>
258 <ol>
259 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
260 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
261 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
262 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
263 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
264 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
265 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
266 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
267 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
268 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
269 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
270 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
271 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
272 </ol>
273 </li>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]274 <li><a href="#int_memorymarkers">Memory Use Markers</a>
275 <ol>
276 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
277 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
278 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
279 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
280 </ol>
281 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]282 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]283 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]284 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]285 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]286 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]287 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]288 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]289 '<tt>llvm.trap</tt>' Intrinsic</a></li>
290 <li><a href="#int_stackprotector">
291 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]292 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]293 </li>
294 </ol>
295 </li>
296</ol>
297
298<div class="doc_author">
299 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
300 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
301</div>
302
303<!-- *********************************************************************** -->
304<div class="doc_section"> <a name="abstract">Abstract </a></div>
305<!-- *********************************************************************** -->
306
307<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]308
309<p>This document is a reference manual for the LLVM assembly language. LLVM is
310 a Static Single Assignment (SSA) based representation that provides type
311 safety, low-level operations, flexibility, and the capability of representing
312 'all' high-level languages cleanly. It is the common code representation
313 used throughout all phases of the LLVM compilation strategy.</p>
314
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]315</div>
316
317<!-- *********************************************************************** -->
318<div class="doc_section"> <a name="introduction">Introduction</a> </div>
319<!-- *********************************************************************** -->
320
321<div class="doc_text">
322
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]323<p>The LLVM code representation is designed to be used in three different forms:
324 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
325 for fast loading by a Just-In-Time compiler), and as a human readable
326 assembly language representation. This allows LLVM to provide a powerful
327 intermediate representation for efficient compiler transformations and
328 analysis, while providing a natural means to debug and visualize the
329 transformations. The three different forms of LLVM are all equivalent. This
330 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]331
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]332<p>The LLVM representation aims to be light-weight and low-level while being
333 expressive, typed, and extensible at the same time. It aims to be a
334 "universal IR" of sorts, by being at a low enough level that high-level ideas
335 may be cleanly mapped to it (similar to how microprocessors are "universal
336 IR's", allowing many source languages to be mapped to them). By providing
337 type information, LLVM can be used as the target of optimizations: for
338 example, through pointer analysis, it can be proven that a C automatic
339 variable is never accessed outside of the current function... allowing it to
340 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]341
342</div>
343
344<!-- _______________________________________________________________________ -->
345<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
346
347<div class="doc_text">
348
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]349<p>It is important to note that this document describes 'well formed' LLVM
350 assembly language. There is a difference between what the parser accepts and
351 what is considered 'well formed'. For example, the following instruction is
352 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]353
354<div class="doc_code">
355<pre>
356%x = <a href="#i_add">add</a> i32 1, %x
357</pre>
358</div>
359
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]360<p>...because the definition of <tt>%x</tt> does not dominate all of its
361 uses. The LLVM infrastructure provides a verification pass that may be used
362 to verify that an LLVM module is well formed. This pass is automatically run
363 by the parser after parsing input assembly and by the optimizer before it
364 outputs bitcode. The violations pointed out by the verifier pass indicate
365 bugs in transformation passes or input to the parser.</p>
366
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]367</div>
368
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]369<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]370
371<!-- *********************************************************************** -->
372<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
373<!-- *********************************************************************** -->
374
375<div class="doc_text">
376
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]377<p>LLVM identifiers come in two basic types: global and local. Global
378 identifiers (functions, global variables) begin with the <tt>'@'</tt>
379 character. Local identifiers (register names, types) begin with
380 the <tt>'%'</tt> character. Additionally, there are three different formats
381 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]382
383<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]384 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]385 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
386 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
387 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
388 other characters in their names can be surrounded with quotes. Special
389 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
390 ASCII code for the character in hexadecimal. In this way, any character
391 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]392
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]393 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]394 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]395
396 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]397 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]398</ol>
399
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]400<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]401 don't need to worry about name clashes with reserved words, and the set of
402 reserved words may be expanded in the future without penalty. Additionally,
403 unnamed identifiers allow a compiler to quickly come up with a temporary
404 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]405
406<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]407 languages. There are keywords for different opcodes
408 ('<tt><a href="#i_add">add</a></tt>',
409 '<tt><a href="#i_bitcast">bitcast</a></tt>',
410 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
411 ('<tt><a href="#t_void">void</a></tt>',
412 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
413 reserved words cannot conflict with variable names, because none of them
414 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]415
416<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]417 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]418
419<p>The easy way:</p>
420
421<div class="doc_code">
422<pre>
423%result = <a href="#i_mul">mul</a> i32 %X, 8
424</pre>
425</div>
426
427<p>After strength reduction:</p>
428
429<div class="doc_code">
430<pre>
431%result = <a href="#i_shl">shl</a> i32 %X, i8 3
432</pre>
433</div>
434
435<p>And the hard way:</p>
436
437<div class="doc_code">
438<pre>
439<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
440<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
441%result = <a href="#i_add">add</a> i32 %1, %1
442</pre>
443</div>
444
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]445<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
446 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]447
448<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]449 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]450 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]451
452 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]453 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]454
455 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]456</ol>
457
458<p>...and it also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]459 demonstrating instructions, we will follow an instruction with a comment that
460 defines the type and name of value produced. Comments are shown in italic
461 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]462
463</div>
464
465<!-- *********************************************************************** -->
466<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
467<!-- *********************************************************************** -->
468
469<!-- ======================================================================= -->
470<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
471</div>
472
473<div class="doc_text">
474
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]475<p>LLVM programs are composed of "Module"s, each of which is a translation unit
476 of the input programs. Each module consists of functions, global variables,
477 and symbol table entries. Modules may be combined together with the LLVM
478 linker, which merges function (and global variable) definitions, resolves
479 forward declarations, and merges symbol table entries. Here is an example of
480 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]481
482<div class="doc_code">
483<pre><i>; Declare the string constant as a global constant...</i>
484<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
485 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
486
487<i>; External declaration of the puts function</i>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]488<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]489
490<i>; Definition of main function</i>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]491define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]492 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]493 %cast210 = <a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]494 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]495
496 <i>; Call puts function to write out the string to stdout...</i>
497 <a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]498 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]499 <a
500 href="#i_ret">ret</a> i32 0<br>}<br>
501</pre>
502</div>
503
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]504<p>This example is made up of a <a href="#globalvars">global variable</a> named
505 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
506 a <a href="#functionstructure">function definition</a> for
507 "<tt>main</tt>".</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]508
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]509<p>In general, a module is made up of a list of global values, where both
510 functions and global variables are global values. Global values are
511 represented by a pointer to a memory location (in this case, a pointer to an
512 array of char, and a pointer to a function), and have one of the
513 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]514
515</div>
516
517<!-- ======================================================================= -->
518<div class="doc_subsection">
519 <a name="linkage">Linkage Types</a>
520</div>
521
522<div class="doc_text">
523
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]524<p>All Global Variables and Functions have one of the following types of
525 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]526
527<dl>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]528 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]529 <dd>Global values with private linkage are only directly accessible by objects
530 in the current module. In particular, linking code into a module with an
531 private global value may cause the private to be renamed as necessary to
532 avoid collisions. Because the symbol is private to the module, all
533 references can be updated. This doesn't show up in any symbol table in the
534 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]535
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]536 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt>: </dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]537 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattner06c1ecc2009-08-24 04:32:16 +0000[diff] [blame]538 removed by the linker after evaluation. Note that (unlike private
539 symbols) linker_private symbols are subject to coalescing by the linker:
540 weak symbols get merged and redefinitions are rejected. However, unlike
541 normal strong symbols, they are removed by the linker from the final
542 linked image (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]543
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]544 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]545 <dd>Similar to private, but the value shows as a local symbol
546 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
547 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]548
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]550 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]551 into the object file corresponding to the LLVM module. They exist to
552 allow inlining and other optimizations to take place given knowledge of
553 the definition of the global, which is known to be somewhere outside the
554 module. Globals with <tt>available_externally</tt> linkage are allowed to
555 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
556 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]557
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]558 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]559 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]560 the same name when linkage occurs. This is typically used to implement
561 inline functions, templates, or other code which must be generated in each
562 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
563 allowed to be discarded.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]564
565 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]566 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
567 <tt>linkonce</tt> linkage, except that unreferenced globals with
568 <tt>weak</tt> linkage may not be discarded. This is used for globals that
569 are declared "weak" in C source code.</dd>
570
571 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
572 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
573 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
574 global scope.
575 Symbols with "<tt>common</tt>" linkage are merged in the same way as
576 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]577 <tt>common</tt> symbols may not have an explicit section,
578 must have a zero initializer, and may not be marked '<a
579 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
580 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]581
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]582
583 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]584 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]585 pointer to array type. When two global variables with appending linkage
586 are linked together, the two global arrays are appended together. This is
587 the LLVM, typesafe, equivalent of having the system linker append together
588 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]589
590 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]591 <dd>The semantics of this linkage follow the ELF object file model: the symbol
592 is weak until linked, if not linked, the symbol becomes null instead of
593 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]594
Chris Lattner0fee5c22009-10-10 18:26:06 +0000[diff] [blame]595 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt>: </dt>
596 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]597 <dd>Some languages allow differing globals to be merged, such as two functions
598 with different semantics. Other languages, such as <tt>C++</tt>, ensure
599 that only equivalent globals are ever merged (the "one definition rule" -
600 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
601 and <tt>weak_odr</tt> linkage types to indicate that the global will only
602 be merged with equivalent globals. These linkage types are otherwise the
603 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]604
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]605 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]606 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]607 visible, meaning that it participates in linkage and can be used to
608 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]609</dl>
610
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]611<p>The next two types of linkage are targeted for Microsoft Windows platform
612 only. They are designed to support importing (exporting) symbols from (to)
613 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]614
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]615<dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]617 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]618 or variable via a global pointer to a pointer that is set up by the DLL
619 exporting the symbol. On Microsoft Windows targets, the pointer name is
620 formed by combining <code>__imp_</code> and the function or variable
621 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]622
623 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]624 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]625 pointer to a pointer in a DLL, so that it can be referenced with the
626 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
627 name is formed by combining <code>__imp_</code> and the function or
628 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]629</dl>
630
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]631<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
632 another module defined a "<tt>.LC0</tt>" variable and was linked with this
633 one, one of the two would be renamed, preventing a collision. Since
634 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
635 declarations), they are accessible outside of the current module.</p>
636
637<p>It is illegal for a function <i>declaration</i> to have any linkage type
638 other than "externally visible", <tt>dllimport</tt>
639 or <tt>extern_weak</tt>.</p>
640
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]641<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]642 or <tt>weak_odr</tt> linkages.</p>
643
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]644</div>
645
646<!-- ======================================================================= -->
647<div class="doc_subsection">
648 <a name="callingconv">Calling Conventions</a>
649</div>
650
651<div class="doc_text">
652
653<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]654 and <a href="#i_invoke">invokes</a> can all have an optional calling
655 convention specified for the call. The calling convention of any pair of
656 dynamic caller/callee must match, or the behavior of the program is
657 undefined. The following calling conventions are supported by LLVM, and more
658 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]659
660<dl>
661 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]662 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]663 specified) matches the target C calling conventions. This calling
664 convention supports varargs function calls and tolerates some mismatch in
665 the declared prototype and implemented declaration of the function (as
666 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]667
668 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]669 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]670 (e.g. by passing things in registers). This calling convention allows the
671 target to use whatever tricks it wants to produce fast code for the
672 target, without having to conform to an externally specified ABI
673 (Application Binary Interface). Implementations of this convention should
674 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
675 optimization</a> to be supported. This calling convention does not
676 support varargs and requires the prototype of all callees to exactly match
677 the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]678
679 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]680 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]681 as possible under the assumption that the call is not commonly executed.
682 As such, these calls often preserve all registers so that the call does
683 not break any live ranges in the caller side. This calling convention
684 does not support varargs and requires the prototype of all callees to
685 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]686
687 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]688 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]689 target-specific calling conventions to be used. Target specific calling
690 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]691</dl>
692
693<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]694 support Pascal conventions or any other well-known target-independent
695 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]696
697</div>
698
699<!-- ======================================================================= -->
700<div class="doc_subsection">
701 <a name="visibility">Visibility Styles</a>
702</div>
703
704<div class="doc_text">
705
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]706<p>All Global Variables and Functions have one of the following visibility
707 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]708
709<dl>
710 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]711 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]712 that the declaration is visible to other modules and, in shared libraries,
713 means that the declared entity may be overridden. On Darwin, default
714 visibility means that the declaration is visible to other modules. Default
715 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]716
717 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]718 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]719 object if they are in the same shared object. Usually, hidden visibility
720 indicates that the symbol will not be placed into the dynamic symbol
721 table, so no other module (executable or shared library) can reference it
722 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]723
724 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]725 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]726 the dynamic symbol table, but that references within the defining module
727 will bind to the local symbol. That is, the symbol cannot be overridden by
728 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]729</dl>
730
731</div>
732
733<!-- ======================================================================= -->
734<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]735 <a name="namedtypes">Named Types</a>
736</div>
737
738<div class="doc_text">
739
740<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]741 it easier to read the IR and make the IR more condensed (particularly when
742 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]743
744<div class="doc_code">
745<pre>
746%mytype = type { %mytype*, i32 }
747</pre>
748</div>
749
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]750<p>You may give a name to any <a href="#typesystem">type</a> except
751 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
752 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]753
754<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]755 and that you can therefore specify multiple names for the same type. This
756 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
757 uses structural typing, the name is not part of the type. When printing out
758 LLVM IR, the printer will pick <em>one name</em> to render all types of a
759 particular shape. This means that if you have code where two different
760 source types end up having the same LLVM type, that the dumper will sometimes
761 print the "wrong" or unexpected type. This is an important design point and
762 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]763
764</div>
765
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]766<!-- ======================================================================= -->
767<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]768 <a name="globalvars">Global Variables</a>
769</div>
770
771<div class="doc_text">
772
773<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]774 instead of run-time. Global variables may optionally be initialized, may
775 have an explicit section to be placed in, and may have an optional explicit
776 alignment specified. A variable may be defined as "thread_local", which
777 means that it will not be shared by threads (each thread will have a
778 separated copy of the variable). A variable may be defined as a global
779 "constant," which indicates that the contents of the variable
780 will <b>never</b> be modified (enabling better optimization, allowing the
781 global data to be placed in the read-only section of an executable, etc).
782 Note that variables that need runtime initialization cannot be marked
783 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]784
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]785<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
786 constant, even if the final definition of the global is not. This capability
787 can be used to enable slightly better optimization of the program, but
788 requires the language definition to guarantee that optimizations based on the
789 'constantness' are valid for the translation units that do not include the
790 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]791
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]792<p>As SSA values, global variables define pointer values that are in scope
793 (i.e. they dominate) all basic blocks in the program. Global variables
794 always define a pointer to their "content" type because they describe a
795 region of memory, and all memory objects in LLVM are accessed through
796 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]797
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]798<p>A global variable may be declared to reside in a target-specific numbered
799 address space. For targets that support them, address spaces may affect how
800 optimizations are performed and/or what target instructions are used to
801 access the variable. The default address space is zero. The address space
802 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]803
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]804<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]805 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]806
807<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]808 the alignment is set to zero, the alignment of the global is set by the
809 target to whatever it feels convenient. If an explicit alignment is
810 specified, the global is forced to have at least that much alignment. All
811 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]812
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]813<p>For example, the following defines a global in a numbered address space with
814 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]815
816<div class="doc_code">
817<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]818@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]819</pre>
820</div>
821
822</div>
823
824
825<!-- ======================================================================= -->
826<div class="doc_subsection">
827 <a name="functionstructure">Functions</a>
828</div>
829
830<div class="doc_text">
831
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]832<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
833 optional <a href="#linkage">linkage type</a>, an optional
834 <a href="#visibility">visibility style</a>, an optional
835 <a href="#callingconv">calling convention</a>, a return type, an optional
836 <a href="#paramattrs">parameter attribute</a> for the return type, a function
837 name, a (possibly empty) argument list (each with optional
838 <a href="#paramattrs">parameter attributes</a>), optional
839 <a href="#fnattrs">function attributes</a>, an optional section, an optional
840 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
841 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]842
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]843<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
844 optional <a href="#linkage">linkage type</a>, an optional
845 <a href="#visibility">visibility style</a>, an optional
846 <a href="#callingconv">calling convention</a>, a return type, an optional
847 <a href="#paramattrs">parameter attribute</a> for the return type, a function
848 name, a possibly empty list of arguments, an optional alignment, and an
849 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]850
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]851<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]852 (Control Flow Graph) for the function. Each basic block may optionally start
853 with a label (giving the basic block a symbol table entry), contains a list
854 of instructions, and ends with a <a href="#terminators">terminator</a>
855 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]856
857<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]858 executed on entrance to the function, and it is not allowed to have
859 predecessor basic blocks (i.e. there can not be any branches to the entry
860 block of a function). Because the block can have no predecessors, it also
861 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]862
863<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]864 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]865
866<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]867 the alignment is set to zero, the alignment of the function is set by the
868 target to whatever it feels convenient. If an explicit alignment is
869 specified, the function is forced to have at least that much alignment. All
870 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]871
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]872<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]873<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]874<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]875define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]876 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
877 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
878 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
879 [<a href="#gc">gc</a>] { ... }
880</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]881</div>
882
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]883</div>
884
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]885<!-- ======================================================================= -->
886<div class="doc_subsection">
887 <a name="aliasstructure">Aliases</a>
888</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]889
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]890<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]891
892<p>Aliases act as "second name" for the aliasee value (which can be either
893 function, global variable, another alias or bitcast of global value). Aliases
894 may have an optional <a href="#linkage">linkage type</a>, and an
895 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]896
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]897<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]898<div class="doc_code">
899<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]900@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]901</pre>
902</div>
903
904</div>
905
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]906<!-- ======================================================================= -->
907<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]908
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]909<div class="doc_text">
910
911<p>The return type and each parameter of a function type may have a set of
912 <i>parameter attributes</i> associated with them. Parameter attributes are
913 used to communicate additional information about the result or parameters of
914 a function. Parameter attributes are considered to be part of the function,
915 not of the function type, so functions with different parameter attributes
916 can have the same function type.</p>
917
918<p>Parameter attributes are simple keywords that follow the type specified. If
919 multiple parameter attributes are needed, they are space separated. For
920 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]921
922<div class="doc_code">
923<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]924declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]925declare i32 @atoi(i8 zeroext)
926declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]927</pre>
928</div>
929
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]930<p>Note that any attributes for the function result (<tt>nounwind</tt>,
931 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]932
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]933<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]934
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]935<dl>
936 <dt><tt>zeroext</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]937 <dd>This indicates to the code generator that the parameter or return value
938 should be zero-extended to a 32-bit value by the caller (for a parameter)
939 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]940
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]941 <dt><tt>signext</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]942 <dd>This indicates to the code generator that the parameter or return value
943 should be sign-extended to a 32-bit value by the caller (for a parameter)
944 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]945
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]946 <dt><tt>inreg</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]947 <dd>This indicates that this parameter or return value should be treated in a
948 special target-dependent fashion during while emitting code for a function
949 call or return (usually, by putting it in a register as opposed to memory,
950 though some targets use it to distinguish between two different kinds of
951 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]952
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]953 <dt><tt><a name="byval">byval</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]954 <dd>This indicates that the pointer parameter should really be passed by value
955 to the function. The attribute implies that a hidden copy of the pointee
956 is made between the caller and the callee, so the callee is unable to
957 modify the value in the callee. This attribute is only valid on LLVM
958 pointer arguments. It is generally used to pass structs and arrays by
959 value, but is also valid on pointers to scalars. The copy is considered
960 to belong to the caller not the callee (for example,
961 <tt><a href="#readonly">readonly</a></tt> functions should not write to
962 <tt>byval</tt> parameters). This is not a valid attribute for return
963 values. The byval attribute also supports specifying an alignment with
964 the align attribute. This has a target-specific effect on the code
965 generator that usually indicates a desired alignment for the synthesized
966 stack slot.</dd>
967
968 <dt><tt>sret</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]969 <dd>This indicates that the pointer parameter specifies the address of a
970 structure that is the return value of the function in the source program.
971 This pointer must be guaranteed by the caller to be valid: loads and
972 stores to the structure may be assumed by the callee to not to trap. This
973 may only be applied to the first parameter. This is not a valid attribute
974 for return values. </dd>
975
976 <dt><tt>noalias</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]977 <dd>This indicates that the pointer does not alias any global or any other
978 parameter. The caller is responsible for ensuring that this is the
979 case. On a function return value, <tt>noalias</tt> additionally indicates
980 that the pointer does not alias any other pointers visible to the
981 caller. For further details, please see the discussion of the NoAlias
982 response in
983 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
984 analysis</a>.</dd>
985
986 <dt><tt>nocapture</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]987 <dd>This indicates that the callee does not make any copies of the pointer
988 that outlive the callee itself. This is not a valid attribute for return
989 values.</dd>
990
991 <dt><tt>nest</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]992 <dd>This indicates that the pointer parameter can be excised using the
993 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
994 attribute for return values.</dd>
995</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]996
997</div>
998
999<!-- ======================================================================= -->
1000<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1001 <a name="gc">Garbage Collector Names</a>
1002</div>
1003
1004<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1005
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1006<p>Each function may specify a garbage collector name, which is simply a
1007 string:</p>
1008
1009<div class="doc_code">
1010<pre>
1011define void @f() gc "name" { ...
1012</pre>
1013</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1014
1015<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1016 collector which will cause the compiler to alter its output in order to
1017 support the named garbage collection algorithm.</p>
1018
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1019</div>
1020
1021<!-- ======================================================================= -->
1022<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1023 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1024</div>
1025
1026<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1027
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1028<p>Function attributes are set to communicate additional information about a
1029 function. Function attributes are considered to be part of the function, not
1030 of the function type, so functions with different parameter attributes can
1031 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1032
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1033<p>Function attributes are simple keywords that follow the type specified. If
1034 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1035
1036<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1037<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1038define void @f() noinline { ... }
1039define void @f() alwaysinline { ... }
1040define void @f() alwaysinline optsize { ... }
1041define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1042</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1043</div>
1044
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1045<dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1046 <dt><tt>alwaysinline</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1047 <dd>This attribute indicates that the inliner should attempt to inline this
1048 function into callers whenever possible, ignoring any active inlining size
1049 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1050
Dale Johannesen7fd6b0f2009-08-26 01:08:21 +0000[diff] [blame]1051 <dt><tt>inlinehint</tt></dt>
1052 <dd>This attribute indicates that the source code contained a hint that inlining
1053 this function is desirable (such as the "inline" keyword in C/C++). It
1054 is just a hint; it imposes no requirements on the inliner.</dd>
1055
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1056 <dt><tt>noinline</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1057 <dd>This attribute indicates that the inliner should never inline this
1058 function in any situation. This attribute may not be used together with
1059 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1060
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1061 <dt><tt>optsize</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1062 <dd>This attribute suggests that optimization passes and code generator passes
1063 make choices that keep the code size of this function low, and otherwise
1064 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1065
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1066 <dt><tt>noreturn</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1067 <dd>This function attribute indicates that the function never returns
1068 normally. This produces undefined behavior at runtime if the function
1069 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1070
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1071 <dt><tt>nounwind</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1072 <dd>This function attribute indicates that the function never returns with an
1073 unwind or exceptional control flow. If the function does unwind, its
1074 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1075
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1076 <dt><tt>readnone</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1077 <dd>This attribute indicates that the function computes its result (or decides
1078 to unwind an exception) based strictly on its arguments, without
1079 dereferencing any pointer arguments or otherwise accessing any mutable
1080 state (e.g. memory, control registers, etc) visible to caller functions.
1081 It does not write through any pointer arguments
1082 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1083 changes any state visible to callers. This means that it cannot unwind
1084 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1085 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1086
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1087 <dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1088 <dd>This attribute indicates that the function does not write through any
1089 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1090 arguments) or otherwise modify any state (e.g. memory, control registers,
1091 etc) visible to caller functions. It may dereference pointer arguments
1092 and read state that may be set in the caller. A readonly function always
1093 returns the same value (or unwinds an exception identically) when called
1094 with the same set of arguments and global state. It cannot unwind an
1095 exception by calling the <tt>C++</tt> exception throwing methods, but may
1096 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1097
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1098 <dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1099 <dd>This attribute indicates that the function should emit a stack smashing
1100 protector. It is in the form of a "canary"&mdash;a random value placed on
1101 the stack before the local variables that's checked upon return from the
1102 function to see if it has been overwritten. A heuristic is used to
1103 determine if a function needs stack protectors or not.<br>
1104<br>
1105 If a function that has an <tt>ssp</tt> attribute is inlined into a
1106 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1107 function will have an <tt>ssp</tt> attribute.</dd>
1108
1109 <dt><tt>sspreq</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1110 <dd>This attribute indicates that the function should <em>always</em> emit a
1111 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1112 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1113<br>
1114 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1115 function that doesn't have an <tt>sspreq</tt> attribute or which has
1116 an <tt>ssp</tt> attribute, then the resulting function will have
1117 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1118
1119 <dt><tt>noredzone</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1120 <dd>This attribute indicates that the code generator should not use a red
1121 zone, even if the target-specific ABI normally permits it.</dd>
1122
1123 <dt><tt>noimplicitfloat</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1124 <dd>This attributes disables implicit floating point instructions.</dd>
1125
1126 <dt><tt>naked</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1127 <dd>This attribute disables prologue / epilogue emission for the function.
1128 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1129</dl>
1130
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1131</div>
1132
1133<!-- ======================================================================= -->
1134<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1135 <a name="moduleasm">Module-Level Inline Assembly</a>
1136</div>
1137
1138<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1139
1140<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1141 the GCC "file scope inline asm" blocks. These blocks are internally
1142 concatenated by LLVM and treated as a single unit, but may be separated in
1143 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1144
1145<div class="doc_code">
1146<pre>
1147module asm "inline asm code goes here"
1148module asm "more can go here"
1149</pre>
1150</div>
1151
1152<p>The strings can contain any character by escaping non-printable characters.
1153 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]1154 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1155
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1156<p>The inline asm code is simply printed to the machine code .s file when
1157 assembly code is generated.</p>
1158
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1159</div>
1160
1161<!-- ======================================================================= -->
1162<div class="doc_subsection">
1163 <a name="datalayout">Data Layout</a>
1164</div>
1165
1166<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1167
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1168<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1169 data is to be laid out in memory. The syntax for the data layout is
1170 simply:</p>
1171
1172<div class="doc_code">
1173<pre>
1174target datalayout = "<i>layout specification</i>"
1175</pre>
1176</div>
1177
1178<p>The <i>layout specification</i> consists of a list of specifications
1179 separated by the minus sign character ('-'). Each specification starts with
1180 a letter and may include other information after the letter to define some
1181 aspect of the data layout. The specifications accepted are as follows:</p>
1182
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1183<dl>
1184 <dt><tt>E</tt></dt>
1185 <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]1186 bits with the most significance have the lowest address location.</dd>
1187
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1188 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1189 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1190 the bits with the least significance have the lowest address
1191 location.</dd>
1192
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1193 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1194 <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]1195 <i>preferred</i> alignments. All sizes are in bits. Specifying
1196 the <i>pref</i> alignment is optional. If omitted, the
1197 preceding <tt>:</tt> should be omitted too.</dd>
1198
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1199 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1200 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1201 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1202
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1203 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1204 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1205 <i>size</i>.</dd>
1206
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1207 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1208 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1209 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1210 (double).</dd>
1211
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1212 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1213 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1214 <i>size</i>.</dd>
1215
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1216 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1217 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1218 <i>size</i>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1219</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1220
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1221<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1222 default set of specifications which are then (possibly) overriden by the
1223 specifications in the <tt>datalayout</tt> keyword. The default specifications
1224 are given in this list:</p>
1225
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1226<ul>
1227 <li><tt>E</tt> - big endian</li>
1228 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1229 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1230 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1231 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1232 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1233 <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]1234 alignment of 64-bits</li>
1235 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1236 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1237 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1238 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1239 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1240 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1241</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1242
1243<p>When LLVM is determining the alignment for a given type, it uses the
1244 following rules:</p>
1245
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1246<ol>
1247 <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]1248 specification is used.</li>
1249
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1250 <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]1251 smallest integer type that is larger than the bitwidth of the sought type
1252 is used. If none of the specifications are larger than the bitwidth then
1253 the the largest integer type is used. For example, given the default
1254 specifications above, the i7 type will use the alignment of i8 (next
1255 largest) while both i65 and i256 will use the alignment of i64 (largest
1256 specified).</li>
1257
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1258 <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]1259 largest vector type that is smaller than the sought vector type will be
1260 used as a fall back. This happens because &lt;128 x double&gt; can be
1261 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1262</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1263
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1264</div>
1265
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1266<!-- ======================================================================= -->
1267<div class="doc_subsection">
1268 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1269</div>
1270
1271<div class="doc_text">
1272
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1273<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1274with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1275is undefined. Pointer values are associated with address ranges
1276according to the following rules:</p>
1277
1278<ul>
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1279 <li>A pointer value formed from a
1280 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1281 is associated with the addresses associated with the first operand
1282 of the <tt>getelementptr</tt>.</li>
1283 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1284 range of the variable's storage.</li>
1285 <li>The result value of an allocation instruction is associated with
1286 the address range of the allocated storage.</li>
1287 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1288 no address.</li>
1289 <li>A pointer value formed by an
1290 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1291 address ranges of all pointer values that contribute (directly or
1292 indirectly) to the computation of the pointer's value.</li>
1293 <li>The result value of a
1294 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1295 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1296 <li>An integer constant other than zero or a pointer value returned
1297 from a function not defined within LLVM may be associated with address
1298 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1299 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1300 allocated by mechanisms provided by LLVM.</li>
1301 </ul>
1302
1303<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1304<tt><a href="#i_load">load</a></tt> merely indicates the size and
1305alignment of the memory from which to load, as well as the
1306interpretation of the value. The first operand of a
1307<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1308and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1309
1310<p>Consequently, type-based alias analysis, aka TBAA, aka
1311<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1312LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1313additional information which specialized optimization passes may use
1314to implement type-based alias analysis.</p>
1315
1316</div>
1317
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1318<!-- *********************************************************************** -->
1319<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1320<!-- *********************************************************************** -->
1321
1322<div class="doc_text">
1323
1324<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1325 intermediate representation. Being typed enables a number of optimizations
1326 to be performed on the intermediate representation directly, without having
1327 to do extra analyses on the side before the transformation. A strong type
1328 system makes it easier to read the generated code and enables novel analyses
1329 and transformations that are not feasible to perform on normal three address
1330 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1331
1332</div>
1333
1334<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1335<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1336Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1337
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1338<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1339
1340<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1341
1342<table border="1" cellspacing="0" cellpadding="4">
1343 <tbody>
1344 <tr><th>Classification</th><th>Types</th></tr>
1345 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1346 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1347 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1348 </tr>
1349 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1350 <td><a href="#t_floating">floating point</a></td>
1351 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1352 </tr>
1353 <tr>
1354 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1355 <td><a href="#t_integer">integer</a>,
1356 <a href="#t_floating">floating point</a>,
1357 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1358 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1359 <a href="#t_struct">structure</a>,
1360 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1361 <a href="#t_label">label</a>,
1362 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1363 </td>
1364 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1365 <tr>
1366 <td><a href="#t_primitive">primitive</a></td>
1367 <td><a href="#t_label">label</a>,
1368 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1369 <a href="#t_floating">floating point</a>,
1370 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1371 </tr>
1372 <tr>
1373 <td><a href="#t_derived">derived</a></td>
1374 <td><a href="#t_integer">integer</a>,
1375 <a href="#t_array">array</a>,
1376 <a href="#t_function">function</a>,
1377 <a href="#t_pointer">pointer</a>,
1378 <a href="#t_struct">structure</a>,
1379 <a href="#t_pstruct">packed structure</a>,
1380 <a href="#t_vector">vector</a>,
1381 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1382 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1383 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1384 </tbody>
1385</table>
1386
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1387<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1388 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1389 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1390
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1391</div>
1392
1393<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1394<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1395
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1396<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1397
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1398<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1399 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1400
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1401</div>
1402
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1403<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1404<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1405
1406<div class="doc_text">
1407
1408<h5>Overview:</h5>
1409<p>The integer type is a very simple type that simply specifies an arbitrary
1410 bit width for the integer type desired. Any bit width from 1 bit to
1411 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1412
1413<h5>Syntax:</h5>
1414<pre>
1415 iN
1416</pre>
1417
1418<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1419 value.</p>
1420
1421<h5>Examples:</h5>
1422<table class="layout">
1423 <tr class="layout">
1424 <td class="left"><tt>i1</tt></td>
1425 <td class="left">a single-bit integer.</td>
1426 </tr>
1427 <tr class="layout">
1428 <td class="left"><tt>i32</tt></td>
1429 <td class="left">a 32-bit integer.</td>
1430 </tr>
1431 <tr class="layout">
1432 <td class="left"><tt>i1942652</tt></td>
1433 <td class="left">a really big integer of over 1 million bits.</td>
1434 </tr>
1435</table>
1436
1437<p>Note that the code generator does not yet support large integer types to be
1438 used as function return types. The specific limit on how large a return type
1439 the code generator can currently handle is target-dependent; currently it's
1440 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
1441
1442</div>
1443
1444<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1445<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1446
1447<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1448
1449<table>
1450 <tbody>
1451 <tr><th>Type</th><th>Description</th></tr>
1452 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1453 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1454 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1455 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1456 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1457 </tbody>
1458</table>
1459
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1460</div>
1461
1462<!-- _______________________________________________________________________ -->
1463<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1464
1465<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1466
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1467<h5>Overview:</h5>
1468<p>The void type does not represent any value and has no size.</p>
1469
1470<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1471<pre>
1472 void
1473</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1474
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1475</div>
1476
1477<!-- _______________________________________________________________________ -->
1478<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1479
1480<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1481
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1482<h5>Overview:</h5>
1483<p>The label type represents code labels.</p>
1484
1485<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1486<pre>
1487 label
1488</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1489
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1490</div>
1491
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1492<!-- _______________________________________________________________________ -->
1493<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1494
1495<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1496
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1497<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1498<p>The metadata type represents embedded metadata. No derived types may be
1499 created from metadata except for <a href="#t_function">function</a>
1500 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1501
1502<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1503<pre>
1504 metadata
1505</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1506
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1507</div>
1508
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1509
1510<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1511<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1512
1513<div class="doc_text">
1514
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1515<p>The real power in LLVM comes from the derived types in the system. This is
1516 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1517 useful types. Each of these types contain one or more element types which
1518 may be a primitive type, or another derived type. For example, it is
1519 possible to have a two dimensional array, using an array as the element type
1520 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1521
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1522</div>
1523
1524<!-- _______________________________________________________________________ -->
1525<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1526
1527<div class="doc_text">
1528
1529<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1530<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1531 sequentially in memory. The array type requires a size (number of elements)
1532 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1533
1534<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1535<pre>
1536 [&lt;# elements&gt; x &lt;elementtype&gt;]
1537</pre>
1538
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1539<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1540 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1541
1542<h5>Examples:</h5>
1543<table class="layout">
1544 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1545 <td class="left"><tt>[40 x i32]</tt></td>
1546 <td class="left">Array of 40 32-bit integer values.</td>
1547 </tr>
1548 <tr class="layout">
1549 <td class="left"><tt>[41 x i32]</tt></td>
1550 <td class="left">Array of 41 32-bit integer values.</td>
1551 </tr>
1552 <tr class="layout">
1553 <td class="left"><tt>[4 x i8]</tt></td>
1554 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1555 </tr>
1556</table>
1557<p>Here are some examples of multidimensional arrays:</p>
1558<table class="layout">
1559 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1560 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1561 <td class="left">3x4 array of 32-bit integer values.</td>
1562 </tr>
1563 <tr class="layout">
1564 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1565 <td class="left">12x10 array of single precision floating point values.</td>
1566 </tr>
1567 <tr class="layout">
1568 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1569 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1570 </tr>
1571</table>
1572
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1573<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1574 length array. Normally, accesses past the end of an array are undefined in
1575 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1576 a special case, however, zero length arrays are recognized to be variable
1577 length. This allows implementation of 'pascal style arrays' with the LLVM
1578 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1579
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1580<p>Note that the code generator does not yet support large aggregate types to be
1581 used as function return types. The specific limit on how large an aggregate
1582 return type the code generator can currently handle is target-dependent, and
1583 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1584
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1585</div>
1586
1587<!-- _______________________________________________________________________ -->
1588<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1590<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1591
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1592<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1593<p>The function type can be thought of as a function signature. It consists of
1594 a return type and a list of formal parameter types. The return type of a
1595 function type is a scalar type, a void type, or a struct type. If the return
1596 type is a struct type then all struct elements must be of first class types,
1597 and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1598
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1599<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1600<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1601 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1602</pre>
1603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1604<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]1605 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1606 which indicates that the function takes a variable number of arguments.
1607 Variable argument functions can access their arguments with
1608 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1609 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1610 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1611
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1612<h5>Examples:</h5>
1613<table class="layout">
1614 <tr class="layout">
1615 <td class="left"><tt>i32 (i32)</tt></td>
1616 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1617 </td>
1618 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1619 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1620 </tt></td>
1621 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1622 an <tt>i16</tt> that should be sign extended and a
1623 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1624 <tt>float</tt>.
1625 </td>
1626 </tr><tr class="layout">
1627 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1628 <td class="left">A vararg function that takes at least one
1629 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1630 which returns an integer. This is the signature for <tt>printf</tt> in
1631 LLVM.
1632 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1633 </tr><tr class="layout">
1634 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1635 <td class="left">A function taking an <tt>i32</tt>, returning a
1636 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1637 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1638 </tr>
1639</table>
1640
1641</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1642
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1643<!-- _______________________________________________________________________ -->
1644<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1645
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1646<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1647
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1648<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1649<p>The structure type is used to represent a collection of data members together
1650 in memory. The packing of the field types is defined to match the ABI of the
1651 underlying processor. The elements of a structure may be any type that has a
1652 size.</p>
1653
1654<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1655 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1656 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1657
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1658<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1659<pre>
1660 { &lt;type list&gt; }
1661</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1663<h5>Examples:</h5>
1664<table class="layout">
1665 <tr class="layout">
1666 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1667 <td class="left">A triple of three <tt>i32</tt> values</td>
1668 </tr><tr class="layout">
1669 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1670 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1671 second element is a <a href="#t_pointer">pointer</a> to a
1672 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1673 an <tt>i32</tt>.</td>
1674 </tr>
1675</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1676
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1677<p>Note that the code generator does not yet support large aggregate types to be
1678 used as function return types. The specific limit on how large an aggregate
1679 return type the code generator can currently handle is target-dependent, and
1680 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1681
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1682</div>
1683
1684<!-- _______________________________________________________________________ -->
1685<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1686</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1687
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1688<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1689
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1690<h5>Overview:</h5>
1691<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1692 together in memory. There is no padding between fields. Further, the
1693 alignment of a packed structure is 1 byte. The elements of a packed
1694 structure may be any type that has a size.</p>
1695
1696<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1697 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1698 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1699
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1700<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1701<pre>
1702 &lt; { &lt;type list&gt; } &gt;
1703</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1705<h5>Examples:</h5>
1706<table class="layout">
1707 <tr class="layout">
1708 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1709 <td class="left">A triple of three <tt>i32</tt> values</td>
1710 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1711 <td class="left">
1712<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1713 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1714 second element is a <a href="#t_pointer">pointer</a> to a
1715 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1716 an <tt>i32</tt>.</td>
1717 </tr>
1718</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1719
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1720</div>
1721
1722<!-- _______________________________________________________________________ -->
1723<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1724
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1725<div class="doc_text">
1726
1727<h5>Overview:</h5>
1728<p>As in many languages, the pointer type represents a pointer or reference to
1729 another object, which must live in memory. Pointer types may have an optional
1730 address space attribute defining the target-specific numbered address space
1731 where the pointed-to object resides. The default address space is zero.</p>
1732
1733<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1734 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1735
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1736<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1737<pre>
1738 &lt;type&gt; *
1739</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1740
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1741<h5>Examples:</h5>
1742<table class="layout">
1743 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1744 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1745 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1746 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1747 </tr>
1748 <tr class="layout">
1749 <td class="left"><tt>i32 (i32 *) *</tt></td>
1750 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1751 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1752 <tt>i32</tt>.</td>
1753 </tr>
1754 <tr class="layout">
1755 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1756 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1757 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1758 </tr>
1759</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1760
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1761</div>
1762
1763<!-- _______________________________________________________________________ -->
1764<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1765
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1766<div class="doc_text">
1767
1768<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1769<p>A vector type is a simple derived type that represents a vector of elements.
1770 Vector types are used when multiple primitive data are operated in parallel
1771 using a single instruction (SIMD). A vector type requires a size (number of
1772 elements) and an underlying primitive data type. Vectors must have a power
1773 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1774 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1775
1776<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1777<pre>
1778 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1779</pre>
1780
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1781<p>The number of elements is a constant integer value; elementtype may be any
1782 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1783
1784<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1785<table class="layout">
1786 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1787 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1788 <td class="left">Vector of 4 32-bit integer values.</td>
1789 </tr>
1790 <tr class="layout">
1791 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1792 <td class="left">Vector of 8 32-bit floating-point values.</td>
1793 </tr>
1794 <tr class="layout">
1795 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1796 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1797 </tr>
1798</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1799
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1800<p>Note that the code generator does not yet support large vector types to be
1801 used as function return types. The specific limit on how large a vector
1802 return type codegen can currently handle is target-dependent; currently it's
1803 often a few times longer than a hardware vector register.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1804
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1805</div>
1806
1807<!-- _______________________________________________________________________ -->
1808<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1809<div class="doc_text">
1810
1811<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1812<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1813 corresponds (for example) to the C notion of a forward declared structure
1814 type. In LLVM, opaque types can eventually be resolved to any type (not just
1815 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1816
1817<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1818<pre>
1819 opaque
1820</pre>
1821
1822<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1823<table class="layout">
1824 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1825 <td class="left"><tt>opaque</tt></td>
1826 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1827 </tr>
1828</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1829
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1830</div>
1831
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1832<!-- ======================================================================= -->
1833<div class="doc_subsection">
1834 <a name="t_uprefs">Type Up-references</a>
1835</div>
1836
1837<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1838
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1839<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1840<p>An "up reference" allows you to refer to a lexically enclosing type without
1841 requiring it to have a name. For instance, a structure declaration may
1842 contain a pointer to any of the types it is lexically a member of. Example
1843 of up references (with their equivalent as named type declarations)
1844 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1845
1846<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1847 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1848 { \2 }* %y = type { %y }*
1849 \1* %z = type %z*
1850</pre>
1851
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1852<p>An up reference is needed by the asmprinter for printing out cyclic types
1853 when there is no declared name for a type in the cycle. Because the
1854 asmprinter does not want to print out an infinite type string, it needs a
1855 syntax to handle recursive types that have no names (all names are optional
1856 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1857
1858<h5>Syntax:</h5>
1859<pre>
1860 \&lt;level&gt;
1861</pre>
1862
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1863<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]1864
1865<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1866<table class="layout">
1867 <tr class="layout">
1868 <td class="left"><tt>\1*</tt></td>
1869 <td class="left">Self-referential pointer.</td>
1870 </tr>
1871 <tr class="layout">
1872 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1873 <td class="left">Recursive structure where the upref refers to the out-most
1874 structure.</td>
1875 </tr>
1876</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1877
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1878</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1879
1880<!-- *********************************************************************** -->
1881<div class="doc_section"> <a name="constants">Constants</a> </div>
1882<!-- *********************************************************************** -->
1883
1884<div class="doc_text">
1885
1886<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1887 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1888
1889</div>
1890
1891<!-- ======================================================================= -->
1892<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1893
1894<div class="doc_text">
1895
1896<dl>
1897 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1898 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1899 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1900
1901 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1902 <dd>Standard integers (such as '4') are constants of
1903 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1904 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1905
1906 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1907 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1908 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1909 notation (see below). The assembler requires the exact decimal value of a
1910 floating-point constant. For example, the assembler accepts 1.25 but
1911 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1912 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1913
1914 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1915 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1916 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1917</dl>
1918
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1919<p>The one non-intuitive notation for constants is the hexadecimal form of
1920 floating point constants. For example, the form '<tt>double
1921 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1922 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1923 constants are required (and the only time that they are generated by the
1924 disassembler) is when a floating point constant must be emitted but it cannot
1925 be represented as a decimal floating point number in a reasonable number of
1926 digits. For example, NaN's, infinities, and other special values are
1927 represented in their IEEE hexadecimal format so that assembly and disassembly
1928 do not cause any bits to change in the constants.</p>
1929
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1930<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1931 represented using the 16-digit form shown above (which matches the IEEE754
1932 representation for double); float values must, however, be exactly
1933 representable as IEE754 single precision. Hexadecimal format is always used
1934 for long double, and there are three forms of long double. The 80-bit format
1935 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1936 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1937 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1938 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1939 currently supported target uses this format. Long doubles will only work if
1940 they match the long double format on your target. All hexadecimal formats
1941 are big-endian (sign bit at the left).</p>
1942
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1943</div>
1944
1945<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1946<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]1947<a name="aggregateconstants"></a> <!-- old anchor -->
1948<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1949</div>
1950
1951<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1952
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1953<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1954 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1955
1956<dl>
1957 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1958 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1959 type definitions (a comma separated list of elements, surrounded by braces
1960 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1961 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1962 Structure constants must have <a href="#t_struct">structure type</a>, and
1963 the number and types of elements must match those specified by the
1964 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1965
1966 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1967 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1968 definitions (a comma separated list of elements, surrounded by square
1969 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1970 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1971 the number and types of elements must match those specified by the
1972 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1973
1974 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1975 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1976 definitions (a comma separated list of elements, surrounded by
1977 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1978 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1979 have <a href="#t_vector">vector type</a>, and the number and types of
1980 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1981
1982 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1983 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1984 value to zero of <em>any</em> type, including scalar and aggregate types.
1985 This is often used to avoid having to print large zero initializers
1986 (e.g. for large arrays) and is always exactly equivalent to using explicit
1987 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1988
1989 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]1990 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1991 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1992 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1993 be interpreted as part of the instruction stream, metadata is a place to
1994 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1995</dl>
1996
1997</div>
1998
1999<!-- ======================================================================= -->
2000<div class="doc_subsection">
2001 <a name="globalconstants">Global Variable and Function Addresses</a>
2002</div>
2003
2004<div class="doc_text">
2005
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2006<p>The addresses of <a href="#globalvars">global variables</a>
2007 and <a href="#functionstructure">functions</a> are always implicitly valid
2008 (link-time) constants. These constants are explicitly referenced when
2009 the <a href="#identifiers">identifier for the global</a> is used and always
2010 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2011 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2012
2013<div class="doc_code">
2014<pre>
2015@X = global i32 17
2016@Y = global i32 42
2017@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2018</pre>
2019</div>
2020
2021</div>
2022
2023<!-- ======================================================================= -->
2024<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2025<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2026
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2027<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]2028 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2029 Undefined values may be of any type (other than label or void) and be used
2030 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2031
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2032<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2033 program is well defined no matter what value is used. This gives the
2034 compiler more freedom to optimize. Here are some examples of (potentially
2035 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2036
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2037
2038<div class="doc_code">
2039<pre>
2040 %A = add %X, undef
2041 %B = sub %X, undef
2042 %C = xor %X, undef
2043Safe:
2044 %A = undef
2045 %B = undef
2046 %C = undef
2047</pre>
2048</div>
2049
2050<p>This is safe because all of the output bits are affected by the undef bits.
2051Any output bit can have a zero or one depending on the input bits.</p>
2052
2053<div class="doc_code">
2054<pre>
2055 %A = or %X, undef
2056 %B = and %X, undef
2057Safe:
2058 %A = -1
2059 %B = 0
2060Unsafe:
2061 %A = undef
2062 %B = undef
2063</pre>
2064</div>
2065
2066<p>These logical operations have bits that are not always affected by the input.
2067For example, if "%X" has a zero bit, then the output of the 'and' operation will
2068always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2069such, it is unsafe to optimize or assume that the result of the and is undef.
2070However, it is safe to assume that all bits of the undef could be 0, and
2071optimize the and to 0. Likewise, it is safe to assume that all the bits of
2072the undef operand to the or could be set, allowing the or to be folded to
2073-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2074
2075<div class="doc_code">
2076<pre>
2077 %A = select undef, %X, %Y
2078 %B = select undef, 42, %Y
2079 %C = select %X, %Y, undef
2080Safe:
2081 %A = %X (or %Y)
2082 %B = 42 (or %Y)
2083 %C = %Y
2084Unsafe:
2085 %A = undef
2086 %B = undef
2087 %C = undef
2088</pre>
2089</div>
2090
2091<p>This set of examples show that undefined select (and conditional branch)
2092conditions can go "either way" but they have to come from one of the two
2093operands. In the %A example, if %X and %Y were both known to have a clear low
2094bit, then %A would have to have a cleared low bit. However, in the %C example,
2095the optimizer is allowed to assume that the undef operand could be the same as
2096%Y, allowing the whole select to be eliminated.</p>
2097
2098
2099<div class="doc_code">
2100<pre>
2101 %A = xor undef, undef
2102
2103 %B = undef
2104 %C = xor %B, %B
2105
2106 %D = undef
2107 %E = icmp lt %D, 4
2108 %F = icmp gte %D, 4
2109
2110Safe:
2111 %A = undef
2112 %B = undef
2113 %C = undef
2114 %D = undef
2115 %E = undef
2116 %F = undef
2117</pre>
2118</div>
2119
2120<p>This example points out that two undef operands are not necessarily the same.
2121This can be surprising to people (and also matches C semantics) where they
2122assume that "X^X" is always zero, even if X is undef. This isn't true for a
2123number of reasons, but the short answer is that an undef "variable" can
2124arbitrarily change its value over its "live range". This is true because the
2125"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2126logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2127so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2128to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2129would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2130
2131<div class="doc_code">
2132<pre>
2133 %A = fdiv undef, %X
2134 %B = fdiv %X, undef
2135Safe:
2136 %A = undef
2137b: unreachable
2138</pre>
2139</div>
2140
2141<p>These examples show the crucial difference between an <em>undefined
2142value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2143allowed to have an arbitrary bit-pattern. This means that the %A operation
2144can be constant folded to undef because the undef could be an SNaN, and fdiv is
2145not (currently) defined on SNaN's. However, in the second example, we can make
2146a more aggressive assumption: because the undef is allowed to be an arbitrary
2147value, 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]2148has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2149does not execute at all. This allows us to delete the divide and all code after
2150it: since the undefined operation "can't happen", the optimizer can assume that
2151it occurs in dead code.
2152</p>
2153
2154<div class="doc_code">
2155<pre>
2156a: store undef -> %X
2157b: store %X -> undef
2158Safe:
2159a: &lt;deleted&gt;
2160b: unreachable
2161</pre>
2162</div>
2163
2164<p>These examples reiterate the fdiv example: a store "of" an undefined value
2165can be assumed to not have any effect: we can assume that the value is
2166overwritten with bits that happen to match what was already there. However, a
2167store "to" an undefined location could clobber arbitrary memory, therefore, it
2168has undefined behavior.</p>
2169
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2170</div>
2171
2172<!-- ======================================================================= -->
2173<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2174</div>
2175
2176<div class="doc_text">
2177
2178<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2179 to be used as constants. Constant expressions may be of
2180 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2181 operation that does not have side effects (e.g. load and call are not
2182 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2183
2184<dl>
2185 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2186 <dd>Truncate a constant to another type. The bit size of CST must be larger
2187 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2188
2189 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2190 <dd>Zero extend a constant to another type. The bit size of CST must be
2191 smaller or equal to the bit size of TYPE. Both types must be
2192 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2193
2194 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2195 <dd>Sign extend a constant to another type. The bit size of CST must be
2196 smaller or equal to the bit size of TYPE. Both types must be
2197 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2198
2199 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2200 <dd>Truncate a floating point constant to another floating point type. The
2201 size of CST must be larger than the size of TYPE. Both types must be
2202 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2203
2204 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2205 <dd>Floating point extend a constant to another type. The size of CST must be
2206 smaller or equal to the size of TYPE. Both types must be floating
2207 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2208
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2209 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2210 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2211 constant. TYPE must be a scalar or vector integer type. CST must be of
2212 scalar or vector floating point type. Both CST and TYPE must be scalars,
2213 or vectors of the same number of elements. If the value won't fit in the
2214 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2215
2216 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2217 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2218 constant. TYPE must be a scalar or vector integer type. CST must be of
2219 scalar or vector floating point type. Both CST and TYPE must be scalars,
2220 or vectors of the same number of elements. If the value won't fit in the
2221 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2222
2223 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2224 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2225 constant. TYPE must be a scalar or vector floating point type. CST must be
2226 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2227 vectors of the same number of elements. If the value won't fit in the
2228 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2229
2230 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2231 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2232 constant. TYPE must be a scalar or vector floating point type. CST must be
2233 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2234 vectors of the same number of elements. If the value won't fit in the
2235 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2236
2237 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2238 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2239 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2240 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2241 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2242
2243 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2244 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2245 type. CST must be of integer type. The CST value is zero extended,
2246 truncated, or unchanged to make it fit in a pointer size. This one is
2247 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2248
2249 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2250 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2251 are the same as those for the <a href="#i_bitcast">bitcast
2252 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2253
2254 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2255 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2256 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2257 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2258 instruction, the index list may have zero or more indexes, which are
2259 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2260
2261 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2262 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2263
2264 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2265 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2266
2267 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2268 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2269
2270 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2271 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2272 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2273
2274 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2275 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2276 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2277
2278 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2279 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2280 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2281
2282 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2283 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2284 be any of the <a href="#binaryops">binary</a>
2285 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2286 on operands are the same as those for the corresponding instruction
2287 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2288</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2289
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2290</div>
2291
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2292<!-- ======================================================================= -->
2293<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2294</div>
2295
2296<div class="doc_text">
2297
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2298<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2299 stream without affecting the behaviour of the program. There are two
2300 metadata primitives, strings and nodes. All metadata has the
2301 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2302 point ('<tt>!</tt>').</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2303
2304<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2305 any character by escaping non-printable characters with "\xx" where "xx" is
2306 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2307
2308<p>Metadata nodes are represented with notation similar to structure constants
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2309 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2310 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2311 10}</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2312
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2313<p>A metadata node will attempt to track changes to the values it holds. In the
2314 event that a value is deleted, it will be replaced with a typeless
2315 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2316
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2317<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2318 the program that isn't available in the instructions, or that isn't easily
2319 computable. Similarly, the code generator may expect a certain metadata
2320 format to be used to express debugging information.</p>
2321
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2322</div>
2323
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2324<!-- *********************************************************************** -->
2325<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2326<!-- *********************************************************************** -->
2327
2328<!-- ======================================================================= -->
2329<div class="doc_subsection">
2330<a name="inlineasm">Inline Assembler Expressions</a>
2331</div>
2332
2333<div class="doc_text">
2334
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2335<p>LLVM supports inline assembler expressions (as opposed
2336 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2337 a special value. This value represents the inline assembler as a string
2338 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2339 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2340 expression has side effects, and a flag indicating whether the function
2341 containing the asm needs to align its stack conservatively. An example
2342 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2343
2344<div class="doc_code">
2345<pre>
2346i32 (i32) asm "bswap $0", "=r,r"
2347</pre>
2348</div>
2349
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2350<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2351 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2352 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2353
2354<div class="doc_code">
2355<pre>
2356%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2357</pre>
2358</div>
2359
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2360<p>Inline asms with side effects not visible in the constraint list must be
2361 marked as having side effects. This is done through the use of the
2362 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2363
2364<div class="doc_code">
2365<pre>
2366call void asm sideeffect "eieio", ""()
2367</pre>
2368</div>
2369
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2370<p>In some cases inline asms will contain code that will not work unless the
2371 stack is aligned in some way, such as calls or SSE instructions on x86,
2372 yet will not contain code that does that alignment within the asm.
2373 The compiler should make conservative assumptions about what the asm might
2374 contain and should generate its usual stack alignment code in the prologue
2375 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2376
2377<div class="doc_code">
2378<pre>
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2379call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2380</pre>
2381</div>
2382
2383<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2384 first.</p>
2385
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2386<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2387 documented here. Constraints on what can be done (e.g. duplication, moving,
2388 etc need to be documented). This is probably best done by reference to
2389 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2390
2391</div>
2392
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2393
2394<!-- *********************************************************************** -->
2395<div class="doc_section">
2396 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2397</div>
2398<!-- *********************************************************************** -->
2399
2400<p>LLVM has a number of "magic" global variables that contain data that affect
2401code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2402of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2403section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2404by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2405
2406<!-- ======================================================================= -->
2407<div class="doc_subsection">
2408<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2409</div>
2410
2411<div class="doc_text">
2412
2413<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2414href="#linkage_appending">appending linkage</a>. This array contains a list of
2415pointers to global variables and functions which may optionally have a pointer
2416cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2417
2418<pre>
2419 @X = global i8 4
2420 @Y = global i32 123
2421
2422 @llvm.used = appending global [2 x i8*] [
2423 i8* @X,
2424 i8* bitcast (i32* @Y to i8*)
2425 ], section "llvm.metadata"
2426</pre>
2427
2428<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2429compiler, assembler, and linker are required to treat the symbol as if there is
2430a reference to the global that it cannot see. For example, if a variable has
2431internal linkage and no references other than that from the <tt>@llvm.used</tt>
2432list, it cannot be deleted. This is commonly used to represent references from
2433inline asms and other things the compiler cannot "see", and corresponds to
2434"attribute((used))" in GNU C.</p>
2435
2436<p>On some targets, the code generator must emit a directive to the assembler or
2437object file to prevent the assembler and linker from molesting the symbol.</p>
2438
2439</div>
2440
2441<!-- ======================================================================= -->
2442<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2443<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2444</div>
2445
2446<div class="doc_text">
2447
2448<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2449<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2450touching the symbol. On targets that support it, this allows an intelligent
2451linker to optimize references to the symbol without being impeded as it would be
2452by <tt>@llvm.used</tt>.</p>
2453
2454<p>This is a rare construct that should only be used in rare circumstances, and
2455should not be exposed to source languages.</p>
2456
2457</div>
2458
2459<!-- ======================================================================= -->
2460<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2461<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2462</div>
2463
2464<div class="doc_text">
2465
2466<p>TODO: Describe this.</p>
2467
2468</div>
2469
2470<!-- ======================================================================= -->
2471<div class="doc_subsection">
2472<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2473</div>
2474
2475<div class="doc_text">
2476
2477<p>TODO: Describe this.</p>
2478
2479</div>
2480
2481
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2482<!-- *********************************************************************** -->
2483<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2484<!-- *********************************************************************** -->
2485
2486<div class="doc_text">
2487
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2488<p>The LLVM instruction set consists of several different classifications of
2489 instructions: <a href="#terminators">terminator
2490 instructions</a>, <a href="#binaryops">binary instructions</a>,
2491 <a href="#bitwiseops">bitwise binary instructions</a>,
2492 <a href="#memoryops">memory instructions</a>, and
2493 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2494
2495</div>
2496
2497<!-- ======================================================================= -->
2498<div class="doc_subsection"> <a name="terminators">Terminator
2499Instructions</a> </div>
2500
2501<div class="doc_text">
2502
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2503<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2504 in a program ends with a "Terminator" instruction, which indicates which
2505 block should be executed after the current block is finished. These
2506 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2507 control flow, not values (the one exception being the
2508 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2509
2510<p>There are six different terminator instructions: the
2511 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2512 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2513 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
2514 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2515 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2516 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2517
2518</div>
2519
2520<!-- _______________________________________________________________________ -->
2521<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2522Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2524<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2525
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2526<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2527<pre>
2528 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]2529 ret void <i>; Return from void function</i>
2530</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2531
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2532<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2533<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2534 a value) from a function back to the caller.</p>
2535
2536<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2537 value and then causes control flow, and one that just causes control flow to
2538 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2539
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2540<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2541<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2542 return value. The type of the return value must be a
2543 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2544
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2545<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2546 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2547 value or a return value with a type that does not match its type, or if it
2548 has a void return type and contains a '<tt>ret</tt>' instruction with a
2549 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2550
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2551<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2552<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2553 the calling function's context. If the caller is a
2554 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2555 instruction after the call. If the caller was an
2556 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2557 the beginning of the "normal" destination block. If the instruction returns
2558 a value, that value shall set the call or invoke instruction's return
2559 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2560
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2561<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2562<pre>
2563 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2564 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2565 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]2566</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2567
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2568<p>Note that the code generator does not yet fully support large
2569 return values. The specific sizes that are currently supported are
2570 dependent on the target. For integers, on 32-bit targets the limit
2571 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2572 For aggregate types, the current limits are dependent on the element
2573 types; for example targets are often limited to 2 total integer
2574 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2575
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2576</div>
2577<!-- _______________________________________________________________________ -->
2578<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2579
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2580<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2581
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2582<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2583<pre>
2584 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]2585</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2586
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2587<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2588<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2589 different basic block in the current function. There are two forms of this
2590 instruction, corresponding to a conditional branch and an unconditional
2591 branch.</p>
2592
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2593<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2594<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2595 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2596 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2597 target.</p>
2598
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2599<h5>Semantics:</h5>
2600<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2601 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2602 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2603 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2604
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2605<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2606<pre>
2607Test:
2608 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2609 br i1 %cond, label %IfEqual, label %IfUnequal
2610IfEqual:
2611 <a href="#i_ret">ret</a> i32 1
2612IfUnequal:
2613 <a href="#i_ret">ret</a> i32 0
2614</pre>
2615
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2616</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2617
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2618<!-- _______________________________________________________________________ -->
2619<div class="doc_subsubsection">
2620 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2621</div>
2622
2623<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2624
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2625<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2626<pre>
2627 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2628</pre>
2629
2630<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2631<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]2632 several different places. It is a generalization of the '<tt>br</tt>'
2633 instruction, allowing a branch to occur to one of many possible
2634 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2635
2636<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2637<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2638 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2639 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2640 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2641
2642<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2643<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2644 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2645 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2646 transferred to the corresponding destination; otherwise, control flow is
2647 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2648
2649<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2650<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2651 <tt>switch</tt> instruction, this instruction may be code generated in
2652 different ways. For example, it could be generated as a series of chained
2653 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2654
2655<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2656<pre>
2657 <i>; Emulate a conditional br instruction</i>
2658 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2659 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2660
2661 <i>; Emulate an unconditional br instruction</i>
2662 switch i32 0, label %dest [ ]
2663
2664 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2665 switch i32 %val, label %otherwise [ i32 0, label %onzero
2666 i32 1, label %onone
2667 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2668</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2669
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2670</div>
2671
2672<!-- _______________________________________________________________________ -->
2673<div class="doc_subsubsection">
2674 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2675</div>
2676
2677<div class="doc_text">
2678
2679<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2680<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2681 &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]2682 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2683</pre>
2684
2685<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2686<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2687 function, with the possibility of control flow transfer to either the
2688 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2689 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2690 control flow will return to the "normal" label. If the callee (or any
2691 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2692 instruction, control is interrupted and continued at the dynamically nearest
2693 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2694
2695<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2696<p>This instruction requires several arguments:</p>
2697
2698<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2699 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2700 convention</a> the call should use. If none is specified, the call
2701 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2702
2703 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2704 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2705 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2706
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2707 <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]2708 function value being invoked. In most cases, this is a direct function
2709 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2710 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2711
2712 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2713 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2714
2715 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2716 signature argument types. If the function signature indicates the
2717 function accepts a variable number of arguments, the extra arguments can
2718 be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2719
2720 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2721 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2722
2723 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2724 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2725
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2726 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2727 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2728 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2729</ol>
2730
2731<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2732<p>This instruction is designed to operate as a standard
2733 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2734 primary difference is that it establishes an association with a label, which
2735 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2736
2737<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2738 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2739 exception. Additionally, this is important for implementation of
2740 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2741
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2742<p>For the purposes of the SSA form, the definition of the value returned by the
2743 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2744 block to the "normal" label. If the callee unwinds then no return value is
2745 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2746
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2747<h5>Example:</h5>
2748<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2749 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2750 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2751 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2752 unwind label %TestCleanup <i>; {i32}:retval set</i>
2753</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2754
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2755</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2756
2757<!-- _______________________________________________________________________ -->
2758
2759<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2760Instruction</a> </div>
2761
2762<div class="doc_text">
2763
2764<h5>Syntax:</h5>
2765<pre>
2766 unwind
2767</pre>
2768
2769<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2770<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2771 at the first callee in the dynamic call stack which used
2772 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2773 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2774
2775<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2776<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2777 immediately halt. The dynamic call stack is then searched for the
2778 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2779 Once found, execution continues at the "exceptional" destination block
2780 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2781 instruction in the dynamic call chain, undefined behavior results.</p>
2782
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2783</div>
2784
2785<!-- _______________________________________________________________________ -->
2786
2787<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2788Instruction</a> </div>
2789
2790<div class="doc_text">
2791
2792<h5>Syntax:</h5>
2793<pre>
2794 unreachable
2795</pre>
2796
2797<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2798<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2799 instruction is used to inform the optimizer that a particular portion of the
2800 code is not reachable. This can be used to indicate that the code after a
2801 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2802
2803<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2804<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2805
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2806</div>
2807
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2808<!-- ======================================================================= -->
2809<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2810
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2811<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2812
2813<p>Binary operators are used to do most of the computation in a program. They
2814 require two operands of the same type, execute an operation on them, and
2815 produce a single value. The operands might represent multiple data, as is
2816 the case with the <a href="#t_vector">vector</a> data type. The result value
2817 has the same type as its operands.</p>
2818
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2819<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2820
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2821</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2822
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2823<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2824<div class="doc_subsubsection">
2825 <a name="i_add">'<tt>add</tt>' Instruction</a>
2826</div>
2827
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2828<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2829
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2830<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2831<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2832 &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]2833 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2834 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2835 &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]2836</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2838<h5>Overview:</h5>
2839<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2840
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2841<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2842<p>The two arguments to the '<tt>add</tt>' instruction must
2843 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2844 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2845
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2846<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2847<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2848
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2849<p>If the sum has unsigned overflow, the result returned is the mathematical
2850 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]2851
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2852<p>Because LLVM integers use a two's complement representation, this instruction
2853 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2854
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2855<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2856 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2857 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2858 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2859
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2860<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2861<pre>
2862 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2863</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2864
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2865</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2866
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2867<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2868<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2869 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2870</div>
2871
2872<div class="doc_text">
2873
2874<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2875<pre>
2876 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2877</pre>
2878
2879<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2880<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2881
2882<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2883<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2884 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2885 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2886
2887<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2888<p>The value produced is the floating point sum of the two operands.</p>
2889
2890<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2891<pre>
2892 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2893</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2894
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2895</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2896
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2897<!-- _______________________________________________________________________ -->
2898<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2899 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2900</div>
2901
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2902<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2903
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2904<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2905<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2906 &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]2907 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2908 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2909 &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]2910</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2911
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2912<h5>Overview:</h5>
2913<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2914 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2915
2916<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2917 '<tt>neg</tt>' instruction present in most other intermediate
2918 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2919
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2920<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2921<p>The two arguments to the '<tt>sub</tt>' instruction must
2922 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2923 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2924
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2925<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2926<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2927
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2928<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2929 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2930 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2931
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2932<p>Because LLVM integers use a two's complement representation, this instruction
2933 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2934
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2935<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2936 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2937 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2938 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2939
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2940<h5>Example:</h5>
2941<pre>
2942 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2943 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2944</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2945
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2946</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2947
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2948<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2949<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2950 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2951</div>
2952
2953<div class="doc_text">
2954
2955<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2956<pre>
2957 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2958</pre>
2959
2960<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2961<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2962 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2963
2964<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2965 '<tt>fneg</tt>' instruction present in most other intermediate
2966 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2967
2968<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2969<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2970 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2971 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2972
2973<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2974<p>The value produced is the floating point difference of the two operands.</p>
2975
2976<h5>Example:</h5>
2977<pre>
2978 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2979 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2980</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2981
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2982</div>
2983
2984<!-- _______________________________________________________________________ -->
2985<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2986 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2987</div>
2988
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2989<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2990
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2991<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2992<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2993 &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]2994 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2995 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2996 &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]2997</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2998
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2999<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3000<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3001
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3002<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3003<p>The two arguments to the '<tt>mul</tt>' instruction must
3004 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3005 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3006
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3007<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3008<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3009
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3010<p>If the result of the multiplication has unsigned overflow, the result
3011 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3012 width of the result.</p>
3013
3014<p>Because LLVM integers use a two's complement representation, and the result
3015 is the same width as the operands, this instruction returns the correct
3016 result for both signed and unsigned integers. If a full product
3017 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3018 be sign-extended or zero-extended as appropriate to the width of the full
3019 product.</p>
3020
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3021<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3022 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3023 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3024 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3025
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3026<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3027<pre>
3028 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3029</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3030
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3031</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3032
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3033<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3034<div class="doc_subsubsection">
3035 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3036</div>
3037
3038<div class="doc_text">
3039
3040<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3041<pre>
3042 &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]3043</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3044
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3045<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3046<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3047
3048<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3049<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3050 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3051 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3052
3053<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3054<p>The value produced is the floating point product of the two operands.</p>
3055
3056<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3057<pre>
3058 &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]3059</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3060
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3061</div>
3062
3063<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3064<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3065</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3066
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3067<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3068
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3069<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3070<pre>
3071 &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]3072</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3073
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3074<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3075<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3076
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3077<h5>Arguments:</h5>
3078<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3079 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3080 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3081
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3082<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3083<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3084
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3085<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3086 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3087
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3088<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3089
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3090<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3091<pre>
3092 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3093</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3094
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3095</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3096
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3097<!-- _______________________________________________________________________ -->
3098<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3099</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3100
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3101<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3102
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3103<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3104<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3105 &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]3106 &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]3107</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3108
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3109<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3110<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3111
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3112<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3113<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3114 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3115 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3116
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3117<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3118<p>The value produced is the signed integer quotient of the two operands rounded
3119 towards zero.</p>
3120
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3121<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3122 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3123
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3124<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3125 undefined behavior; this is a rare case, but can occur, for example, by doing
3126 a 32-bit division of -2147483648 by -1.</p>
3127
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3128<p>If the <tt>exact</tt> keyword is present, the result value of the
3129 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3130 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3131
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3132<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3133<pre>
3134 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3135</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3136
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3137</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3138
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3139<!-- _______________________________________________________________________ -->
3140<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3141Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3142
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3143<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3144
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3145<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3146<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3147 &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]3148</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3149
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3150<h5>Overview:</h5>
3151<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3152
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3153<h5>Arguments:</h5>
3154<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3155 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3156 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3157
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3158<h5>Semantics:</h5>
3159<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3160
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3161<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3162<pre>
3163 &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]3164</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3165
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3166</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3167
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3168<!-- _______________________________________________________________________ -->
3169<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3170</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3171
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3172<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3173
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3174<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3175<pre>
3176 &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]3177</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3178
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3179<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3180<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3181 division of its two arguments.</p>
3182
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3183<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3184<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3185 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3186 values. Both arguments must have identical types.</p>
3187
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3188<h5>Semantics:</h5>
3189<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3190 This instruction always performs an unsigned division to get the
3191 remainder.</p>
3192
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3193<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3194 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3195
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3196<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3197
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3198<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3199<pre>
3200 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3201</pre>
3202
3203</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3204
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3205<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3206<div class="doc_subsubsection">
3207 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3208</div>
3209
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3210<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3211
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3212<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3213<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3214 &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]3215</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3216
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3217<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3218<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3219 division of its two operands. This instruction can also take
3220 <a href="#t_vector">vector</a> versions of the values in which case the
3221 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3222
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3223<h5>Arguments:</h5>
3224<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3225 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3226 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3228<h5>Semantics:</h5>
3229<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3230 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3231 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3232 a value. For more information about the difference,
3233 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3234 Math Forum</a>. For a table of how this is implemented in various languages,
3235 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3236 Wikipedia: modulo operation</a>.</p>
3237
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3238<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3239 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3240
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3241<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3242 Overflow also leads to undefined behavior; this is a rare case, but can
3243 occur, for example, by taking the remainder of a 32-bit division of
3244 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3245 lets srem be implemented using instructions that return both the result of
3246 the division and the remainder.)</p>
3247
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3248<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3249<pre>
3250 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3251</pre>
3252
3253</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3254
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3255<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3256<div class="doc_subsubsection">
3257 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3258
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3259<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3260
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3261<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3262<pre>
3263 &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]3264</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3265
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3266<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3267<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3268 its two operands.</p>
3269
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3270<h5>Arguments:</h5>
3271<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3272 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3273 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3274
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3275<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3276<p>This instruction returns the <i>remainder</i> of a division. The remainder
3277 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3279<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3280<pre>
3281 &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]3282</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3283
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3284</div>
3285
3286<!-- ======================================================================= -->
3287<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3288Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3289
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3290<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3291
3292<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3293 program. They are generally very efficient instructions and can commonly be
3294 strength reduced from other instructions. They require two operands of the
3295 same type, execute an operation on them, and produce a single value. The
3296 resulting value is the same type as its operands.</p>
3297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3298</div>
3299
3300<!-- _______________________________________________________________________ -->
3301<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3302Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3303
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3304<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3305
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3306<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3307<pre>
3308 &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]3309</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3310
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3311<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3312<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3313 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3314
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3315<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3316<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3317 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3318 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3319
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3320<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3321<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3322 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3323 is (statically or dynamically) negative or equal to or larger than the number
3324 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3325 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3326 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3327
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3328<h5>Example:</h5>
3329<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3330 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3331 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3332 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3333 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3334 &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]3335</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3336
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3337</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3338
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3339<!-- _______________________________________________________________________ -->
3340<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3341Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3342
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3343<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3344
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3345<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3346<pre>
3347 &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]3348</pre>
3349
3350<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3351<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3352 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3353
3354<h5>Arguments:</h5>
3355<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3356 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3357 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3358
3359<h5>Semantics:</h5>
3360<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3361 significant bits of the result will be filled with zero bits after the shift.
3362 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3363 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3364 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3365 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3366
3367<h5>Example:</h5>
3368<pre>
3369 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3370 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3371 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3372 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3373 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3374 &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]3375</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3376
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3377</div>
3378
3379<!-- _______________________________________________________________________ -->
3380<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3381Instruction</a> </div>
3382<div class="doc_text">
3383
3384<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3385<pre>
3386 &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]3387</pre>
3388
3389<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3390<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3391 operand shifted to the right a specified number of bits with sign
3392 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3393
3394<h5>Arguments:</h5>
3395<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3396 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3397 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3398
3399<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3400<p>This instruction always performs an arithmetic shift right operation, The
3401 most significant bits of the result will be filled with the sign bit
3402 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3403 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3404 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3405 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3406
3407<h5>Example:</h5>
3408<pre>
3409 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3410 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3411 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3412 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3413 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3414 &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]3415</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3416
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3417</div>
3418
3419<!-- _______________________________________________________________________ -->
3420<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3421Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3422
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3423<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3424
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3425<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3426<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3427 &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]3428</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3429
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3430<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3431<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3432 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3433
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3434<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3435<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3436 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3437 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3438
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3439<h5>Semantics:</h5>
3440<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3441
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3442<table border="1" cellspacing="0" cellpadding="4">
3443 <tbody>
3444 <tr>
3445 <td>In0</td>
3446 <td>In1</td>
3447 <td>Out</td>
3448 </tr>
3449 <tr>
3450 <td>0</td>
3451 <td>0</td>
3452 <td>0</td>
3453 </tr>
3454 <tr>
3455 <td>0</td>
3456 <td>1</td>
3457 <td>0</td>
3458 </tr>
3459 <tr>
3460 <td>1</td>
3461 <td>0</td>
3462 <td>0</td>
3463 </tr>
3464 <tr>
3465 <td>1</td>
3466 <td>1</td>
3467 <td>1</td>
3468 </tr>
3469 </tbody>
3470</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3471
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3472<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3473<pre>
3474 &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]3475 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3476 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3477</pre>
3478</div>
3479<!-- _______________________________________________________________________ -->
3480<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3481
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3482<div class="doc_text">
3483
3484<h5>Syntax:</h5>
3485<pre>
3486 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3487</pre>
3488
3489<h5>Overview:</h5>
3490<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3491 two operands.</p>
3492
3493<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3494<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3495 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3496 values. Both arguments must have identical types.</p>
3497
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3498<h5>Semantics:</h5>
3499<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3501<table border="1" cellspacing="0" cellpadding="4">
3502 <tbody>
3503 <tr>
3504 <td>In0</td>
3505 <td>In1</td>
3506 <td>Out</td>
3507 </tr>
3508 <tr>
3509 <td>0</td>
3510 <td>0</td>
3511 <td>0</td>
3512 </tr>
3513 <tr>
3514 <td>0</td>
3515 <td>1</td>
3516 <td>1</td>
3517 </tr>
3518 <tr>
3519 <td>1</td>
3520 <td>0</td>
3521 <td>1</td>
3522 </tr>
3523 <tr>
3524 <td>1</td>
3525 <td>1</td>
3526 <td>1</td>
3527 </tr>
3528 </tbody>
3529</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3530
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3531<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3532<pre>
3533 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3534 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3535 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3536</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3537
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3538</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3539
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3540<!-- _______________________________________________________________________ -->
3541<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3542Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3543
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3544<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3545
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3546<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3547<pre>
3548 &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]3549</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3550
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3551<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3552<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3553 its two operands. The <tt>xor</tt> is used to implement the "one's
3554 complement" operation, which is the "~" operator in C.</p>
3555
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3556<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3557<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3558 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3559 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3560
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3561<h5>Semantics:</h5>
3562<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3563
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3564<table border="1" cellspacing="0" cellpadding="4">
3565 <tbody>
3566 <tr>
3567 <td>In0</td>
3568 <td>In1</td>
3569 <td>Out</td>
3570 </tr>
3571 <tr>
3572 <td>0</td>
3573 <td>0</td>
3574 <td>0</td>
3575 </tr>
3576 <tr>
3577 <td>0</td>
3578 <td>1</td>
3579 <td>1</td>
3580 </tr>
3581 <tr>
3582 <td>1</td>
3583 <td>0</td>
3584 <td>1</td>
3585 </tr>
3586 <tr>
3587 <td>1</td>
3588 <td>1</td>
3589 <td>0</td>
3590 </tr>
3591 </tbody>
3592</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3593
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3594<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3595<pre>
3596 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3597 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3598 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3599 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3600</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3601
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3602</div>
3603
3604<!-- ======================================================================= -->
3605<div class="doc_subsection">
3606 <a name="vectorops">Vector Operations</a>
3607</div>
3608
3609<div class="doc_text">
3610
3611<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3612 target-independent manner. These instructions cover the element-access and
3613 vector-specific operations needed to process vectors effectively. While LLVM
3614 does directly support these vector operations, many sophisticated algorithms
3615 will want to use target-specific intrinsics to take full advantage of a
3616 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3617
3618</div>
3619
3620<!-- _______________________________________________________________________ -->
3621<div class="doc_subsubsection">
3622 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3623</div>
3624
3625<div class="doc_text">
3626
3627<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3628<pre>
3629 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3630</pre>
3631
3632<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3633<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3634 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3635
3636
3637<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3638<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3639 of <a href="#t_vector">vector</a> type. The second operand is an index
3640 indicating the position from which to extract the element. The index may be
3641 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3642
3643<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3644<p>The result is a scalar of the same type as the element type of
3645 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3646 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3647 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3648
3649<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3650<pre>
3651 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3652</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3653
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3654</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3655
3656<!-- _______________________________________________________________________ -->
3657<div class="doc_subsubsection">
3658 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3659</div>
3660
3661<div class="doc_text">
3662
3663<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3664<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3665 &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]3666</pre>
3667
3668<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3669<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3670 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3671
3672<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3673<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3674 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3675 whose type must equal the element type of the first operand. The third
3676 operand is an index indicating the position at which to insert the value.
3677 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3678
3679<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3680<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3681 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3682 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3683 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3684
3685<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3686<pre>
3687 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3688</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3689
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3690</div>
3691
3692<!-- _______________________________________________________________________ -->
3693<div class="doc_subsubsection">
3694 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3695</div>
3696
3697<div class="doc_text">
3698
3699<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3700<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3701 &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]3702</pre>
3703
3704<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3705<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3706 from two input vectors, returning a vector with the same element type as the
3707 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3708
3709<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3710<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3711 with types that match each other. The third argument is a shuffle mask whose
3712 element type is always 'i32'. The result of the instruction is a vector
3713 whose length is the same as the shuffle mask and whose element type is the
3714 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3715
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3716<p>The shuffle mask operand is required to be a constant vector with either
3717 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3718
3719<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3720<p>The elements of the two input vectors are numbered from left to right across
3721 both of the vectors. The shuffle mask operand specifies, for each element of
3722 the result vector, which element of the two input vectors the result element
3723 gets. The element selector may be undef (meaning "don't care") and the
3724 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3725
3726<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3727<pre>
3728 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3729 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3730 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3731 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3732 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3733 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3734 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3735 &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]3736</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3737
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3738</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3739
3740<!-- ======================================================================= -->
3741<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3742 <a name="aggregateops">Aggregate Operations</a>
3743</div>
3744
3745<div class="doc_text">
3746
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3747<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3748
3749</div>
3750
3751<!-- _______________________________________________________________________ -->
3752<div class="doc_subsubsection">
3753 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3754</div>
3755
3756<div class="doc_text">
3757
3758<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3759<pre>
3760 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3761</pre>
3762
3763<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3764<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3765 or array element from an aggregate value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3766
3767<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3768<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3769 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3770 operands are constant indices to specify which value to extract in a similar
3771 manner as indices in a
3772 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3773
3774<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3775<p>The result is the value at the position in the aggregate specified by the
3776 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3777
3778<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3779<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3780 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3781</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3782
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3783</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3784
3785<!-- _______________________________________________________________________ -->
3786<div class="doc_subsubsection">
3787 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3788</div>
3789
3790<div class="doc_text">
3791
3792<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3793<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3794 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3795</pre>
3796
3797<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3798<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3799 array element in an aggregate.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3800
3801
3802<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3803<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3804 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3805 second operand is a first-class value to insert. The following operands are
3806 constant indices indicating the position at which to insert the value in a
3807 similar manner as indices in a
3808 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3809 value to insert must have the same type as the value identified by the
3810 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3811
3812<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3813<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3814 that of <tt>val</tt> except that the value at the position specified by the
3815 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3816
3817<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3818<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3819 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3820</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3821
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3822</div>
3823
3824
3825<!-- ======================================================================= -->
3826<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3827 <a name="memoryops">Memory Access and Addressing Operations</a>
3828</div>
3829
3830<div class="doc_text">
3831
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3832<p>A key design point of an SSA-based representation is how it represents
3833 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]3834 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3835 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3836
3837</div>
3838
3839<!-- _______________________________________________________________________ -->
3840<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3841 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3842</div>
3843
3844<div class="doc_text">
3845
3846<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3847<pre>
3848 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3849</pre>
3850
3851<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3852<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3853 currently executing function, to be automatically released when this function
3854 returns to its caller. The object is always allocated in the generic address
3855 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3856
3857<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3858<p>The '<tt>alloca</tt>' instruction
3859 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3860 runtime stack, returning a pointer of the appropriate type to the program.
3861 If "NumElements" is specified, it is the number of elements allocated,
3862 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3863 specified, the value result of the allocation is guaranteed to be aligned to
3864 at least that boundary. If not specified, or if zero, the target can choose
3865 to align the allocation on any convenient boundary compatible with the
3866 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3867
3868<p>'<tt>type</tt>' may be any sized type.</p>
3869
3870<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3871<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3872 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3873 memory is automatically released when the function returns. The
3874 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3875 variables that must have an address available. When the function returns
3876 (either with the <tt><a href="#i_ret">ret</a></tt>
3877 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3878 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3879
3880<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3881<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3882 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3883 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3884 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3885 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3886</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3887
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3888</div>
3889
3890<!-- _______________________________________________________________________ -->
3891<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3892Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3893
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3894<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3895
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3896<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3897<pre>
3898 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3899 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3900</pre>
3901
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3902<h5>Overview:</h5>
3903<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3904
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3905<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3906<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3907 from which to load. The pointer must point to
3908 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3909 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3910 number or order of execution of this <tt>load</tt> with other
3911 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3912 instructions. </p>
3913
3914<p>The optional constant "align" argument specifies the alignment of the
3915 operation (that is, the alignment of the memory address). A value of 0 or an
3916 omitted "align" argument means that the operation has the preferential
3917 alignment for the target. It is the responsibility of the code emitter to
3918 ensure that the alignment information is correct. Overestimating the
3919 alignment results in an undefined behavior. Underestimating the alignment may
3920 produce less efficient code. An alignment of 1 is always safe.</p>
3921
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3922<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3923<p>The location of memory pointed to is loaded. If the value being loaded is of
3924 scalar type then the number of bytes read does not exceed the minimum number
3925 of bytes needed to hold all bits of the type. For example, loading an
3926 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3927 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3928 is undefined if the value was not originally written using a store of the
3929 same type.</p>
3930
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3931<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3932<pre>
3933 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3934 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3935 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3936</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3937
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3938</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3939
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3940<!-- _______________________________________________________________________ -->
3941<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3942Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3943
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3944<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3945
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3946<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3947<pre>
3948 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3949 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3950</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3951
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3952<h5>Overview:</h5>
3953<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3954
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3955<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3956<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
3957 and an address at which to store it. The type of the
3958 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
3959 the <a href="#t_firstclass">first class</a> type of the
3960 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
3961 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
3962 or order of execution of this <tt>store</tt> with other
3963 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3964 instructions.</p>
3965
3966<p>The optional constant "align" argument specifies the alignment of the
3967 operation (that is, the alignment of the memory address). A value of 0 or an
3968 omitted "align" argument means that the operation has the preferential
3969 alignment for the target. It is the responsibility of the code emitter to
3970 ensure that the alignment information is correct. Overestimating the
3971 alignment results in an undefined behavior. Underestimating the alignment may
3972 produce less efficient code. An alignment of 1 is always safe.</p>
3973
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3974<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3975<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
3976 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
3977 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
3978 does not exceed the minimum number of bytes needed to hold all bits of the
3979 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
3980 writing a value of a type like <tt>i20</tt> with a size that is not an
3981 integral number of bytes, it is unspecified what happens to the extra bits
3982 that do not belong to the type, but they will typically be overwritten.</p>
3983
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3984<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3985<pre>
3986 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3987 store i32 3, i32* %ptr <i>; yields {void}</i>
3988 %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]3989</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3990
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3991</div>
3992
3993<!-- _______________________________________________________________________ -->
3994<div class="doc_subsubsection">
3995 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3996</div>
3997
3998<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3999
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4000<h5>Syntax:</h5>
4001<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4002 &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]4003 &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]4004</pre>
4005
4006<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4007<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4008 subelement of an aggregate data structure. It performs address calculation
4009 only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4010
4011<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4012<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4013 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4014 elements of the aggregate object are indexed. The interpretation of each
4015 index is dependent on the type being indexed into. The first index always
4016 indexes the pointer value given as the first argument, the second index
4017 indexes a value of the type pointed to (not necessarily the value directly
4018 pointed to, since the first index can be non-zero), etc. The first type
4019 indexed into must be a pointer value, subsequent types can be arrays, vectors
4020 and structs. Note that subsequent types being indexed into can never be
4021 pointers, since that would require loading the pointer before continuing
4022 calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4023
4024<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4025 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4026 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4027 vector, integers of any width are allowed, and they are not required to be
4028 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4029
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4030<p>For example, let's consider a C code fragment and how it gets compiled to
4031 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4032
4033<div class="doc_code">
4034<pre>
4035struct RT {
4036 char A;
4037 int B[10][20];
4038 char C;
4039};
4040struct ST {
4041 int X;
4042 double Y;
4043 struct RT Z;
4044};
4045
4046int *foo(struct ST *s) {
4047 return &amp;s[1].Z.B[5][13];
4048}
4049</pre>
4050</div>
4051
4052<p>The LLVM code generated by the GCC frontend is:</p>
4053
4054<div class="doc_code">
4055<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4056%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4057%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4058
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4059define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4060entry:
4061 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4062 ret i32* %reg
4063}
4064</pre>
4065</div>
4066
4067<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4068<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]4069 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4070 }</tt>' type, a structure. The second index indexes into the third element
4071 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4072 i8 }</tt>' type, another structure. The third index indexes into the second
4073 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4074 array. The two dimensions of the array are subscripted into, yielding an
4075 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4076 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4077
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4078<p>Note that it is perfectly legal to index partially through a structure,
4079 returning a pointer to an inner element. Because of this, the LLVM code for
4080 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4081
4082<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4083 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4084 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4085 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4086 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4087 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4088 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4089 ret i32* %t5
4090 }
4091</pre>
4092
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4093<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4094 <tt>getelementptr</tt> is undefined if the base pointer is not an
4095 <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]4096 that would be formed by successive addition of the offsets implied by the
4097 indices to the base address with infinitely precise arithmetic are not an
4098 <i>in bounds</i> address of that allocated object.
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4099 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4100 that point into the object, plus the address one byte past the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4101
4102<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4103 the base address with silently-wrapping two's complement arithmetic, and
4104 the result value of the <tt>getelementptr</tt> may be outside the object
4105 pointed to by the base pointer. The result value may not necessarily be
4106 used to access memory though, even if it happens to point into allocated
4107 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4108 section for more information.</p>
4109
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4110<p>The getelementptr instruction is often confusing. For some more insight into
4111 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4112
4113<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4114<pre>
4115 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4116 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4117 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4118 %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]4119 <i>; yields i8*:eptr</i>
4120 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4121 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4122 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4123</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4124
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4125</div>
4126
4127<!-- ======================================================================= -->
4128<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4129</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4130
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4131<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4132
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4133<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4134 which all take a single operand and a type. They perform various bit
4135 conversions on the operand.</p>
4136
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4137</div>
4138
4139<!-- _______________________________________________________________________ -->
4140<div class="doc_subsubsection">
4141 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4142</div>
4143<div class="doc_text">
4144
4145<h5>Syntax:</h5>
4146<pre>
4147 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4148</pre>
4149
4150<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4151<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4152 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4153
4154<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4155<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4156 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4157 size and type of the result, which must be
4158 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4159 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4160 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4161
4162<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4163<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4164 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4165 source size must be larger than the destination size, <tt>trunc</tt> cannot
4166 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4167
4168<h5>Example:</h5>
4169<pre>
4170 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4171 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4172 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
4173</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4174
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4175</div>
4176
4177<!-- _______________________________________________________________________ -->
4178<div class="doc_subsubsection">
4179 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4180</div>
4181<div class="doc_text">
4182
4183<h5>Syntax:</h5>
4184<pre>
4185 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4186</pre>
4187
4188<h5>Overview:</h5>
4189<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4190 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4191
4192
4193<h5>Arguments:</h5>
4194<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]4195 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4196 also be of <a href="#t_integer">integer</a> type. The bit size of the
4197 <tt>value</tt> must be smaller than the bit size of the destination type,
4198 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4199
4200<h5>Semantics:</h5>
4201<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]4202 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4203
4204<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4205
4206<h5>Example:</h5>
4207<pre>
4208 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4209 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4210</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4211
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4212</div>
4213
4214<!-- _______________________________________________________________________ -->
4215<div class="doc_subsubsection">
4216 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4217</div>
4218<div class="doc_text">
4219
4220<h5>Syntax:</h5>
4221<pre>
4222 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4223</pre>
4224
4225<h5>Overview:</h5>
4226<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4227
4228<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4229<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4230 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4231 also be of <a href="#t_integer">integer</a> type. The bit size of the
4232 <tt>value</tt> must be smaller than the bit size of the destination type,
4233 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4234
4235<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4236<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4237 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4238 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4239
4240<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4241
4242<h5>Example:</h5>
4243<pre>
4244 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4245 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4246</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4247
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4248</div>
4249
4250<!-- _______________________________________________________________________ -->
4251<div class="doc_subsubsection">
4252 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4253</div>
4254
4255<div class="doc_text">
4256
4257<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4258<pre>
4259 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4260</pre>
4261
4262<h5>Overview:</h5>
4263<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4264 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4265
4266<h5>Arguments:</h5>
4267<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4268 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4269 to cast it to. The size of <tt>value</tt> must be larger than the size of
4270 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4271 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4272
4273<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4274<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4275 <a href="#t_floating">floating point</a> type to a smaller
4276 <a href="#t_floating">floating point</a> type. If the value cannot fit
4277 within the destination type, <tt>ty2</tt>, then the results are
4278 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4279
4280<h5>Example:</h5>
4281<pre>
4282 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4283 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4284</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4285
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4286</div>
4287
4288<!-- _______________________________________________________________________ -->
4289<div class="doc_subsubsection">
4290 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4291</div>
4292<div class="doc_text">
4293
4294<h5>Syntax:</h5>
4295<pre>
4296 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4297</pre>
4298
4299<h5>Overview:</h5>
4300<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]4301 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4302
4303<h5>Arguments:</h5>
4304<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4305 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4306 a <a href="#t_floating">floating point</a> type to cast it to. The source
4307 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4308
4309<h5>Semantics:</h5>
4310<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4311 <a href="#t_floating">floating point</a> type to a larger
4312 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4313 used to make a <i>no-op cast</i> because it always changes bits. Use
4314 <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]4315
4316<h5>Example:</h5>
4317<pre>
4318 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4319 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
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_subsubsection">
4326 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4327</div>
4328<div class="doc_text">
4329
4330<h5>Syntax:</h5>
4331<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4332 &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]4333</pre>
4334
4335<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4336<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4337 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4338
4339<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4340<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4341 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4342 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4343 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4344 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4345
4346<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4347<p>The '<tt>fptoui</tt>' instruction converts its
4348 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4349 towards zero) unsigned integer value. If the value cannot fit
4350 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4351
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4352<h5>Example:</h5>
4353<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4354 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4355 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4356 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4357</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4358
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4359</div>
4360
4361<!-- _______________________________________________________________________ -->
4362<div class="doc_subsubsection">
4363 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4364</div>
4365<div class="doc_text">
4366
4367<h5>Syntax:</h5>
4368<pre>
4369 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4370</pre>
4371
4372<h5>Overview:</h5>
4373<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4374 <a href="#t_floating">floating point</a> <tt>value</tt> to
4375 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4376
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4377<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4378<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4379 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4380 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4381 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4382 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4383
4384<h5>Semantics:</h5>
4385<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4386 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4387 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4388 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4390<h5>Example:</h5>
4391<pre>
4392 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4393 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4394 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4395</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4396
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4397</div>
4398
4399<!-- _______________________________________________________________________ -->
4400<div class="doc_subsubsection">
4401 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4402</div>
4403<div class="doc_text">
4404
4405<h5>Syntax:</h5>
4406<pre>
4407 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4408</pre>
4409
4410<h5>Overview:</h5>
4411<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4412 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4413
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4414<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4415<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]4416 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4417 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4418 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4419 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4420
4421<h5>Semantics:</h5>
4422<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4423 integer quantity and converts it to the corresponding floating point
4424 value. If the value cannot fit in the floating point value, the results are
4425 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4426
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4427<h5>Example:</h5>
4428<pre>
4429 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4430 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4431</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4432
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4433</div>
4434
4435<!-- _______________________________________________________________________ -->
4436<div class="doc_subsubsection">
4437 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4438</div>
4439<div class="doc_text">
4440
4441<h5>Syntax:</h5>
4442<pre>
4443 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4444</pre>
4445
4446<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4447<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4448 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4449
4450<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4451<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]4452 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4453 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4454 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4455 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4456
4457<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4458<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4459 quantity and converts it to the corresponding floating point value. If the
4460 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4461
4462<h5>Example:</h5>
4463<pre>
4464 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4465 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4466</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4467
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4468</div>
4469
4470<!-- _______________________________________________________________________ -->
4471<div class="doc_subsubsection">
4472 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4473</div>
4474<div class="doc_text">
4475
4476<h5>Syntax:</h5>
4477<pre>
4478 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4479</pre>
4480
4481<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4482<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4483 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4484
4485<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4486<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4487 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4488 <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]4489
4490<h5>Semantics:</h5>
4491<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4492 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4493 truncating or zero extending that value to the size of the integer type. If
4494 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4495 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4496 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4497 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4498
4499<h5>Example:</h5>
4500<pre>
4501 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4502 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4503</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4504
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4505</div>
4506
4507<!-- _______________________________________________________________________ -->
4508<div class="doc_subsubsection">
4509 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4510</div>
4511<div class="doc_text">
4512
4513<h5>Syntax:</h5>
4514<pre>
4515 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4516</pre>
4517
4518<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4519<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4520 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4521
4522<h5>Arguments:</h5>
4523<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4524 value to cast, and a type to cast it to, which must be a
4525 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4526
4527<h5>Semantics:</h5>
4528<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4529 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4530 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4531 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4532 than the size of a pointer then a zero extension is done. If they are the
4533 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4534
4535<h5>Example:</h5>
4536<pre>
4537 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4538 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4539 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4540</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4541
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4542</div>
4543
4544<!-- _______________________________________________________________________ -->
4545<div class="doc_subsubsection">
4546 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4547</div>
4548<div class="doc_text">
4549
4550<h5>Syntax:</h5>
4551<pre>
4552 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4553</pre>
4554
4555<h5>Overview:</h5>
4556<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4557 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4558
4559<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4560<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4561 non-aggregate first class value, and a type to cast it to, which must also be
4562 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4563 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4564 identical. If the source type is a pointer, the destination type must also be
4565 a pointer. This instruction supports bitwise conversion of vectors to
4566 integers and to vectors of other types (as long as they have the same
4567 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4568
4569<h5>Semantics:</h5>
4570<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4571 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4572 this conversion. The conversion is done as if the <tt>value</tt> had been
4573 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4574 be converted to other pointer types with this instruction. To convert
4575 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4576 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4577
4578<h5>Example:</h5>
4579<pre>
4580 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4581 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4582 %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]4583</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4584
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4585</div>
4586
4587<!-- ======================================================================= -->
4588<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4590<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4591
4592<p>The instructions in this category are the "miscellaneous" instructions, which
4593 defy better classification.</p>
4594
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4595</div>
4596
4597<!-- _______________________________________________________________________ -->
4598<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4599</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4601<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4602
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4603<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4604<pre>
4605 &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]4606</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4607
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4608<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4609<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4610 boolean values based on comparison of its two integer, integer vector, or
4611 pointer operands.</p>
4612
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4613<h5>Arguments:</h5>
4614<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4615 the condition code indicating the kind of comparison to perform. It is not a
4616 value, just a keyword. The possible condition code are:</p>
4617
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4618<ol>
4619 <li><tt>eq</tt>: equal</li>
4620 <li><tt>ne</tt>: not equal </li>
4621 <li><tt>ugt</tt>: unsigned greater than</li>
4622 <li><tt>uge</tt>: unsigned greater or equal</li>
4623 <li><tt>ult</tt>: unsigned less than</li>
4624 <li><tt>ule</tt>: unsigned less or equal</li>
4625 <li><tt>sgt</tt>: signed greater than</li>
4626 <li><tt>sge</tt>: signed greater or equal</li>
4627 <li><tt>slt</tt>: signed less than</li>
4628 <li><tt>sle</tt>: signed less or equal</li>
4629</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4630
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4631<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4632 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4633 typed. They must also be identical types.</p>
4634
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4635<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4636<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4637 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4638 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]4639 result, as follows:</p>
4640
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4641<ol>
4642 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4643 <tt>false</tt> otherwise. No sign interpretation is necessary or
4644 performed.</li>
4645
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4646 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4647 <tt>false</tt> otherwise. No sign interpretation is necessary or
4648 performed.</li>
4649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4650 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4651 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4652
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4653 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4654 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4655 to <tt>op2</tt>.</li>
4656
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4657 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4658 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4659
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4660 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4661 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4663 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4664 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4665
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4666 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4667 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4668 to <tt>op2</tt>.</li>
4669
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4670 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4671 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4672
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4673 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4674 <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]4675</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4676
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4677<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4678 values are compared as if they were integers.</p>
4679
4680<p>If the operands are integer vectors, then they are compared element by
4681 element. The result is an <tt>i1</tt> vector with the same number of elements
4682 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4683
4684<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4685<pre>
4686 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4687 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4688 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4689 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4690 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4691 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4692</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4693
4694<p>Note that the code generator does not yet support vector types with
4695 the <tt>icmp</tt> instruction.</p>
4696
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4697</div>
4698
4699<!-- _______________________________________________________________________ -->
4700<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4701</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4702
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4703<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4705<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4706<pre>
4707 &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]4708</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4709
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4710<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4711<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4712 values based on comparison of its operands.</p>
4713
4714<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]4715(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4716
4717<p>If the operands are floating point vectors, then the result type is a vector
4718 of boolean with the same number of elements as the operands being
4719 compared.</p>
4720
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4721<h5>Arguments:</h5>
4722<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4723 the condition code indicating the kind of comparison to perform. It is not a
4724 value, just a keyword. The possible condition code are:</p>
4725
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4726<ol>
4727 <li><tt>false</tt>: no comparison, always returns false</li>
4728 <li><tt>oeq</tt>: ordered and equal</li>
4729 <li><tt>ogt</tt>: ordered and greater than </li>
4730 <li><tt>oge</tt>: ordered and greater than or equal</li>
4731 <li><tt>olt</tt>: ordered and less than </li>
4732 <li><tt>ole</tt>: ordered and less than or equal</li>
4733 <li><tt>one</tt>: ordered and not equal</li>
4734 <li><tt>ord</tt>: ordered (no nans)</li>
4735 <li><tt>ueq</tt>: unordered or equal</li>
4736 <li><tt>ugt</tt>: unordered or greater than </li>
4737 <li><tt>uge</tt>: unordered or greater than or equal</li>
4738 <li><tt>ult</tt>: unordered or less than </li>
4739 <li><tt>ule</tt>: unordered or less than or equal</li>
4740 <li><tt>une</tt>: unordered or not equal</li>
4741 <li><tt>uno</tt>: unordered (either nans)</li>
4742 <li><tt>true</tt>: no comparison, always returns true</li>
4743</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4744
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4745<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4746 <i>unordered</i> means that either operand may be a QNAN.</p>
4747
4748<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4749 a <a href="#t_floating">floating point</a> type or
4750 a <a href="#t_vector">vector</a> of floating point type. They must have
4751 identical types.</p>
4752
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4753<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4754<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4755 according to the condition code given as <tt>cond</tt>. If the operands are
4756 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4757 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4758 follows:</p>
4759
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4760<ol>
4761 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4762
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4763 <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]4764 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4765
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4766 <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]4767 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4768
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4769 <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]4770 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4771
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4772 <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]4773 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4774
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4775 <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]4776 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4777
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4778 <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]4779 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4780
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4781 <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]4782
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4783 <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]4784 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4785
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4786 <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]4787 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4788
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4789 <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]4790 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4792 <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]4793 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4794
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4795 <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]4796 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4797
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4798 <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]4799 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4800
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4801 <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]4802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4803 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4804</ol>
4805
4806<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4807<pre>
4808 &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]4809 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4810 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4811 &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]4812</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4813
4814<p>Note that the code generator does not yet support vector types with
4815 the <tt>fcmp</tt> instruction.</p>
4816
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4817</div>
4818
4819<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4820<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4821 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4822</div>
4823
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4824<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4825
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4826<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4827<pre>
4828 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4829</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4830
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4831<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4832<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4833 SSA graph representing the function.</p>
4834
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4835<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4836<p>The type of the incoming values is specified with the first type field. After
4837 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4838 one pair for each predecessor basic block of the current block. Only values
4839 of <a href="#t_firstclass">first class</a> type may be used as the value
4840 arguments to the PHI node. Only labels may be used as the label
4841 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4842
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4843<p>There must be no non-phi instructions between the start of a basic block and
4844 the PHI instructions: i.e. PHI instructions must be first in a basic
4845 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4846
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4847<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4848 occur on the edge from the corresponding predecessor block to the current
4849 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4850 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4851
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4852<h5>Semantics:</h5>
4853<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4854 specified by the pair corresponding to the predecessor basic block that
4855 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4856
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4857<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4858<pre>
4859Loop: ; Infinite loop that counts from 0 on up...
4860 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4861 %nextindvar = add i32 %indvar, 1
4862 br label %Loop
4863</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4864
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4865</div>
4866
4867<!-- _______________________________________________________________________ -->
4868<div class="doc_subsubsection">
4869 <a name="i_select">'<tt>select</tt>' Instruction</a>
4870</div>
4871
4872<div class="doc_text">
4873
4874<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4875<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4876 &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>
4877
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4878 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4879</pre>
4880
4881<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4882<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4883 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4884
4885
4886<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4887<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4888 values indicating the condition, and two values of the
4889 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4890 vectors and the condition is a scalar, then entire vectors are selected, not
4891 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4892
4893<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4894<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4895 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4896
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4897<p>If the condition is a vector of i1, then the value arguments must be vectors
4898 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4899
4900<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4901<pre>
4902 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4903</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4904
4905<p>Note that the code generator does not yet support conditions
4906 with vector type.</p>
4907
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4908</div>
4909
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4910<!-- _______________________________________________________________________ -->
4911<div class="doc_subsubsection">
4912 <a name="i_call">'<tt>call</tt>' Instruction</a>
4913</div>
4914
4915<div class="doc_text">
4916
4917<h5>Syntax:</h5>
4918<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4919 &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]4920</pre>
4921
4922<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4923<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4924
4925<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4926<p>This instruction requires several arguments:</p>
4927
4928<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4929 <li>The optional "tail" marker indicates whether the callee function accesses
4930 any allocas or varargs in the caller. If the "tail" marker is present,
4931 the function call is eligible for tail call optimization. Note that calls
4932 may be marked "tail" even if they do not occur before
4933 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4934
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4935 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4936 convention</a> the call should use. If none is specified, the call
4937 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4938
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4939 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4940 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4941 '<tt>inreg</tt>' attributes are valid here.</li>
4942
4943 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
4944 type of the return value. Functions that return no value are marked
4945 <tt><a href="#t_void">void</a></tt>.</li>
4946
4947 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
4948 being invoked. The argument types must match the types implied by this
4949 signature. This type can be omitted if the function is not varargs and if
4950 the function type does not return a pointer to a function.</li>
4951
4952 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4953 be invoked. In most cases, this is a direct function invocation, but
4954 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4955 to function value.</li>
4956
4957 <li>'<tt>function args</tt>': argument list whose types match the function
4958 signature argument types. All arguments must be of
4959 <a href="#t_firstclass">first class</a> type. If the function signature
4960 indicates the function accepts a variable number of arguments, the extra
4961 arguments can be specified.</li>
4962
4963 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
4964 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4965 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4966</ol>
4967
4968<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4969<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
4970 a specified function, with its incoming arguments bound to the specified
4971 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
4972 function, control flow continues with the instruction after the function
4973 call, and the return value of the function is bound to the result
4974 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4975
4976<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4977<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4978 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4979 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4980 %X = tail call i32 @foo() <i>; yields i32</i>
4981 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4982 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4983
4984 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4985 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4986 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4987 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4988 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4989 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4990</pre>
4991
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]4992<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]4993standard C99 library as being the C99 library functions, and may perform
4994optimizations or generate code for them under that assumption. This is
4995something we'd like to change in the future to provide better support for
4996freestanding environments and non-C-based langauges.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]4997
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4998</div>
4999
5000<!-- _______________________________________________________________________ -->
5001<div class="doc_subsubsection">
5002 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5003</div>
5004
5005<div class="doc_text">
5006
5007<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5008<pre>
5009 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5010</pre>
5011
5012<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5013<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5014 the "variable argument" area of a function call. It is used to implement the
5015 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5016
5017<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5018<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5019 argument. It returns a value of the specified argument type and increments
5020 the <tt>va_list</tt> to point to the next argument. The actual type
5021 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5022
5023<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5024<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5025 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5026 to the next argument. For more information, see the variable argument
5027 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5028
5029<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]5030 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5031 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5032
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5033<p><tt>va_arg</tt> is an LLVM instruction instead of
5034 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5035 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5036
5037<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5038<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5039
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5040<p>Note that the code generator does not yet fully support va_arg on many
5041 targets. Also, it does not currently support va_arg with aggregate types on
5042 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5043
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5044</div>
5045
5046<!-- *********************************************************************** -->
5047<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5048<!-- *********************************************************************** -->
5049
5050<div class="doc_text">
5051
5052<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5053 well known names and semantics and are required to follow certain
5054 restrictions. Overall, these intrinsics represent an extension mechanism for
5055 the LLVM language that does not require changing all of the transformations
5056 in LLVM when adding to the language (or the bitcode reader/writer, the
5057 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5058
5059<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5060 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5061 begin with this prefix. Intrinsic functions must always be external
5062 functions: you cannot define the body of intrinsic functions. Intrinsic
5063 functions may only be used in call or invoke instructions: it is illegal to
5064 take the address of an intrinsic function. Additionally, because intrinsic
5065 functions are part of the LLVM language, it is required if any are added that
5066 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5067
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5068<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5069 family of functions that perform the same operation but on different data
5070 types. Because LLVM can represent over 8 million different integer types,
5071 overloading is used commonly to allow an intrinsic function to operate on any
5072 integer type. One or more of the argument types or the result type can be
5073 overloaded to accept any integer type. Argument types may also be defined as
5074 exactly matching a previous argument's type or the result type. This allows
5075 an intrinsic function which accepts multiple arguments, but needs all of them
5076 to be of the same type, to only be overloaded with respect to a single
5077 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5078
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5079<p>Overloaded intrinsics will have the names of its overloaded argument types
5080 encoded into its function name, each preceded by a period. Only those types
5081 which are overloaded result in a name suffix. Arguments whose type is matched
5082 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5083 can take an integer of any width and returns an integer of exactly the same
5084 integer width. This leads to a family of functions such as
5085 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5086 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5087 suffix is required. Because the argument's type is matched against the return
5088 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5089
5090<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5091 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5092
5093</div>
5094
5095<!-- ======================================================================= -->
5096<div class="doc_subsection">
5097 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5098</div>
5099
5100<div class="doc_text">
5101
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5102<p>Variable argument support is defined in LLVM with
5103 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5104 intrinsic functions. These functions are related to the similarly named
5105 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5106
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5107<p>All of these functions operate on arguments that use a target-specific value
5108 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5109 not define what this type is, so all transformations should be prepared to
5110 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5111
5112<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]5113 instruction and the variable argument handling intrinsic functions are
5114 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5115
5116<div class="doc_code">
5117<pre>
5118define i32 @test(i32 %X, ...) {
5119 ; Initialize variable argument processing
5120 %ap = alloca i8*
5121 %ap2 = bitcast i8** %ap to i8*
5122 call void @llvm.va_start(i8* %ap2)
5123
5124 ; Read a single integer argument
5125 %tmp = va_arg i8** %ap, i32
5126
5127 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5128 %aq = alloca i8*
5129 %aq2 = bitcast i8** %aq to i8*
5130 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5131 call void @llvm.va_end(i8* %aq2)
5132
5133 ; Stop processing of arguments.
5134 call void @llvm.va_end(i8* %ap2)
5135 ret i32 %tmp
5136}
5137
5138declare void @llvm.va_start(i8*)
5139declare void @llvm.va_copy(i8*, i8*)
5140declare void @llvm.va_end(i8*)
5141</pre>
5142</div>
5143
5144</div>
5145
5146<!-- _______________________________________________________________________ -->
5147<div class="doc_subsubsection">
5148 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5149</div>
5150
5151
5152<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5153
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5154<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5155<pre>
5156 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5157</pre>
5158
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5159<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5160<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5161 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]5162
5163<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5164<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]5165
5166<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5167<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]5168 macro available in C. In a target-dependent way, it initializes
5169 the <tt>va_list</tt> element to which the argument points, so that the next
5170 call to <tt>va_arg</tt> will produce the first variable argument passed to
5171 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5172 need to know the last argument of the function as the compiler can figure
5173 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5174
5175</div>
5176
5177<!-- _______________________________________________________________________ -->
5178<div class="doc_subsubsection">
5179 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5180</div>
5181
5182<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5183
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5184<h5>Syntax:</h5>
5185<pre>
5186 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5187</pre>
5188
5189<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5190<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5191 which has been initialized previously
5192 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5193 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5194
5195<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5196<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5197
5198<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5199<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]5200 macro available in C. In a target-dependent way, it destroys
5201 the <tt>va_list</tt> element to which the argument points. Calls
5202 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5203 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5204 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5205
5206</div>
5207
5208<!-- _______________________________________________________________________ -->
5209<div class="doc_subsubsection">
5210 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5211</div>
5212
5213<div class="doc_text">
5214
5215<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5216<pre>
5217 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5218</pre>
5219
5220<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5221<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5222 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5223
5224<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5225<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]5226 The second argument is a pointer to a <tt>va_list</tt> element to copy
5227 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5228
5229<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5230<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]5231 macro available in C. In a target-dependent way, it copies the
5232 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5233 element. This intrinsic is necessary because
5234 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5235 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5236
5237</div>
5238
5239<!-- ======================================================================= -->
5240<div class="doc_subsection">
5241 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5242</div>
5243
5244<div class="doc_text">
5245
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5246<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5247Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5248intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5249roots on the stack</a>, as well as garbage collector implementations that
5250require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5251barriers. Front-ends for type-safe garbage collected languages should generate
5252these intrinsics to make use of the LLVM garbage collectors. For more details,
5253see <a href="GarbageCollection.html">Accurate Garbage Collection with
5254LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5255
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5256<p>The garbage collection intrinsics only operate on objects in the generic
5257 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5258
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5259</div>
5260
5261<!-- _______________________________________________________________________ -->
5262<div class="doc_subsubsection">
5263 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5264</div>
5265
5266<div class="doc_text">
5267
5268<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5269<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5270 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5271</pre>
5272
5273<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5274<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]5275 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5276
5277<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5278<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5279 root pointer. The second pointer (which must be either a constant or a
5280 global value address) contains the meta-data to be associated with the
5281 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5282
5283<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5284<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]5285 location. At compile-time, the code generator generates information to allow
5286 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5287 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5288 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5289
5290</div>
5291
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5292<!-- _______________________________________________________________________ -->
5293<div class="doc_subsubsection">
5294 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5295</div>
5296
5297<div class="doc_text">
5298
5299<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5300<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5301 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5302</pre>
5303
5304<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5305<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5306 locations, allowing garbage collector implementations that require read
5307 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5308
5309<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5310<p>The second argument is the address to read from, which should be an address
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5311 allocated from the garbage collector. The first object is a pointer to the
5312 start of the referenced object, if needed by the language runtime (otherwise
5313 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5314
5315<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5316<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5317 instruction, but may be replaced with substantially more complex code by the
5318 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5319 may only be used in a function which <a href="#gc">specifies a GC
5320 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5321
5322</div>
5323
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5324<!-- _______________________________________________________________________ -->
5325<div class="doc_subsubsection">
5326 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5327</div>
5328
5329<div class="doc_text">
5330
5331<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5332<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5333 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5334</pre>
5335
5336<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5337<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5338 locations, allowing garbage collector implementations that require write
5339 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5340
5341<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5342<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]5343 object to store it to, and the third is the address of the field of Obj to
5344 store to. If the runtime does not require a pointer to the object, Obj may
5345 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5346
5347<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5348<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5349 instruction, but may be replaced with substantially more complex code by the
5350 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5351 may only be used in a function which <a href="#gc">specifies a GC
5352 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5353
5354</div>
5355
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5356<!-- ======================================================================= -->
5357<div class="doc_subsection">
5358 <a name="int_codegen">Code Generator Intrinsics</a>
5359</div>
5360
5361<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5362
5363<p>These intrinsics are provided by LLVM to expose special features that may
5364 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5365
5366</div>
5367
5368<!-- _______________________________________________________________________ -->
5369<div class="doc_subsubsection">
5370 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5371</div>
5372
5373<div class="doc_text">
5374
5375<h5>Syntax:</h5>
5376<pre>
5377 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5378</pre>
5379
5380<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5381<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5382 target-specific value indicating the return address of the current function
5383 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5384
5385<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5386<p>The argument to this intrinsic indicates which function to return the address
5387 for. Zero indicates the calling function, one indicates its caller, etc.
5388 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5389
5390<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5391<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5392 indicating the return address of the specified call frame, or zero if it
5393 cannot be identified. The value returned by this intrinsic is likely to be
5394 incorrect or 0 for arguments other than zero, so it should only be used for
5395 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5396
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5397<p>Note that calling this intrinsic does not prevent function inlining or other
5398 aggressive transformations, so the value returned may not be that of the
5399 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5400
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5401</div>
5402
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5403<!-- _______________________________________________________________________ -->
5404<div class="doc_subsubsection">
5405 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5406</div>
5407
5408<div class="doc_text">
5409
5410<h5>Syntax:</h5>
5411<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5412 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5413</pre>
5414
5415<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5416<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5417 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5418
5419<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5420<p>The argument to this intrinsic indicates which function to return the frame
5421 pointer for. Zero indicates the calling function, one indicates its caller,
5422 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5423
5424<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5425<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5426 indicating the frame address of the specified call frame, or zero if it
5427 cannot be identified. The value returned by this intrinsic is likely to be
5428 incorrect or 0 for arguments other than zero, so it should only be used for
5429 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5430
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5431<p>Note that calling this intrinsic does not prevent function inlining or other
5432 aggressive transformations, so the value returned may not be that of the
5433 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5434
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5435</div>
5436
5437<!-- _______________________________________________________________________ -->
5438<div class="doc_subsubsection">
5439 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5440</div>
5441
5442<div class="doc_text">
5443
5444<h5>Syntax:</h5>
5445<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5446 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5447</pre>
5448
5449<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5450<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5451 of the function stack, for use
5452 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5453 useful for implementing language features like scoped automatic variable
5454 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5455
5456<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5457<p>This intrinsic returns a opaque pointer value that can be passed
5458 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5459 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5460 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5461 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5462 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5463 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5464
5465</div>
5466
5467<!-- _______________________________________________________________________ -->
5468<div class="doc_subsubsection">
5469 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5470</div>
5471
5472<div class="doc_text">
5473
5474<h5>Syntax:</h5>
5475<pre>
5476 declare void @llvm.stackrestore(i8 * %ptr)
5477</pre>
5478
5479<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5480<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5481 the function stack to the state it was in when the
5482 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5483 executed. This is useful for implementing language features like scoped
5484 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5485
5486<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5487<p>See the description
5488 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5489
5490</div>
5491
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5492<!-- _______________________________________________________________________ -->
5493<div class="doc_subsubsection">
5494 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5495</div>
5496
5497<div class="doc_text">
5498
5499<h5>Syntax:</h5>
5500<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5501 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]5502</pre>
5503
5504<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5505<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5506 insert a prefetch instruction if supported; otherwise, it is a noop.
5507 Prefetches have no effect on the behavior of the program but can change its
5508 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5509
5510<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5511<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5512 specifier determining if the fetch should be for a read (0) or write (1),
5513 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5514 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5515 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5516
5517<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5518<p>This intrinsic does not modify the behavior of the program. In particular,
5519 prefetches cannot trap and do not produce a value. On targets that support
5520 this intrinsic, the prefetch can provide hints to the processor cache for
5521 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5522
5523</div>
5524
5525<!-- _______________________________________________________________________ -->
5526<div class="doc_subsubsection">
5527 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5528</div>
5529
5530<div class="doc_text">
5531
5532<h5>Syntax:</h5>
5533<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5534 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5535</pre>
5536
5537<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5538<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5539 Counter (PC) in a region of code to simulators and other tools. The method
5540 is target specific, but it is expected that the marker will use exported
5541 symbols to transmit the PC of the marker. The marker makes no guarantees
5542 that it will remain with any specific instruction after optimizations. It is
5543 possible that the presence of a marker will inhibit optimizations. The
5544 intended use is to be inserted after optimizations to allow correlations of
5545 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5546
5547<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5548<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5549
5550<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5551<p>This intrinsic does not modify the behavior of the program. Backends that do
5552 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5553
5554</div>
5555
5556<!-- _______________________________________________________________________ -->
5557<div class="doc_subsubsection">
5558 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5559</div>
5560
5561<div class="doc_text">
5562
5563<h5>Syntax:</h5>
5564<pre>
5565 declare i64 @llvm.readcyclecounter( )
5566</pre>
5567
5568<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5569<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5570 counter register (or similar low latency, high accuracy clocks) on those
5571 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5572 should map to RPCC. As the backing counters overflow quickly (on the order
5573 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5574
5575<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5576<p>When directly supported, reading the cycle counter should not modify any
5577 memory. Implementations are allowed to either return a application specific
5578 value or a system wide value. On backends without support, this is lowered
5579 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5580
5581</div>
5582
5583<!-- ======================================================================= -->
5584<div class="doc_subsection">
5585 <a name="int_libc">Standard C Library Intrinsics</a>
5586</div>
5587
5588<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5589
5590<p>LLVM provides intrinsics for a few important standard C library functions.
5591 These intrinsics allow source-language front-ends to pass information about
5592 the alignment of the pointer arguments to the code generator, providing
5593 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5594
5595</div>
5596
5597<!-- _______________________________________________________________________ -->
5598<div class="doc_subsubsection">
5599 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5600</div>
5601
5602<div class="doc_text">
5603
5604<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5605<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5606 integer bit width. Not all targets support all bit widths however.</p>
5607
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5608<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5609 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5610 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5611 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5612 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5613 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5614 i32 &lt;len&gt;, i32 &lt;align&gt;)
5615 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5616 i64 &lt;len&gt;, i32 &lt;align&gt;)
5617</pre>
5618
5619<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5620<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5621 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5622
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5623<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5624 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5625
5626<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5627<p>The first argument is a pointer to the destination, the second is a pointer
5628 to the source. The third argument is an integer argument specifying the
5629 number of bytes to copy, and the fourth argument is the alignment of the
5630 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5631
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5632<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5633 then the caller guarantees that both the source and destination pointers are
5634 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5635
5636<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5637<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5638 source location to the destination location, which are not allowed to
5639 overlap. It copies "len" bytes of memory over. If the argument is known to
5640 be aligned to some boundary, this can be specified as the fourth argument,
5641 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5642
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5643</div>
5644
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5645<!-- _______________________________________________________________________ -->
5646<div class="doc_subsubsection">
5647 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5648</div>
5649
5650<div class="doc_text">
5651
5652<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5653<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]5654 width. Not all targets support all bit widths however.</p>
5655
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5656<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5657 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5658 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5659 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5660 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5661 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5662 i32 &lt;len&gt;, i32 &lt;align&gt;)
5663 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5664 i64 &lt;len&gt;, i32 &lt;align&gt;)
5665</pre>
5666
5667<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5668<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5669 source location to the destination location. It is similar to the
5670 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5671 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5672
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5673<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5674 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5675
5676<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5677<p>The first argument is a pointer to the destination, the second is a pointer
5678 to the source. The third argument is an integer argument specifying the
5679 number of bytes to copy, and the fourth argument is the alignment of the
5680 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5681
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5682<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5683 then the caller guarantees that the source and destination pointers are
5684 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5685
5686<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5687<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5688 source location to the destination location, which may overlap. It copies
5689 "len" bytes of memory over. If the argument is known to be aligned to some
5690 boundary, this can be specified as the fourth argument, otherwise it should
5691 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5692
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5693</div>
5694
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5695<!-- _______________________________________________________________________ -->
5696<div class="doc_subsubsection">
5697 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5698</div>
5699
5700<div class="doc_text">
5701
5702<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5703<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5704 width. Not all targets support all bit widths however.</p>
5705
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5706<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5707 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5708 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5709 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5710 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5711 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5712 i32 &lt;len&gt;, i32 &lt;align&gt;)
5713 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5714 i64 &lt;len&gt;, i32 &lt;align&gt;)
5715</pre>
5716
5717<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5718<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5719 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5720
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5721<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5722 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5723
5724<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5725<p>The first argument is a pointer to the destination to fill, the second is the
5726 byte value to fill it with, the third argument is an integer argument
5727 specifying the number of bytes to fill, and the fourth argument is the known
5728 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5729
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5730<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5731 then the caller guarantees that the destination pointer is aligned to that
5732 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5733
5734<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5735<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5736 at the destination location. If the argument is known to be aligned to some
5737 boundary, this can be specified as the fourth argument, otherwise it should
5738 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5739
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5740</div>
5741
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5742<!-- _______________________________________________________________________ -->
5743<div class="doc_subsubsection">
5744 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5745</div>
5746
5747<div class="doc_text">
5748
5749<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5750<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5751 floating point or vector of floating point type. Not all targets support all
5752 types however.</p>
5753
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5754<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5755 declare float @llvm.sqrt.f32(float %Val)
5756 declare double @llvm.sqrt.f64(double %Val)
5757 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5758 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5759 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5760</pre>
5761
5762<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5763<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5764 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5765 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5766 behavior for negative numbers other than -0.0 (which allows for better
5767 optimization, because there is no need to worry about errno being
5768 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]5769
5770<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5771<p>The argument and return value are floating point numbers of the same
5772 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5773
5774<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5775<p>This function returns the sqrt of the specified operand if it is a
5776 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5777
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5778</div>
5779
5780<!-- _______________________________________________________________________ -->
5781<div class="doc_subsubsection">
5782 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5783</div>
5784
5785<div class="doc_text">
5786
5787<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5788<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5789 floating point or vector of floating point type. Not all targets support all
5790 types however.</p>
5791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5792<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5793 declare float @llvm.powi.f32(float %Val, i32 %power)
5794 declare double @llvm.powi.f64(double %Val, i32 %power)
5795 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5796 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5797 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5798</pre>
5799
5800<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5801<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5802 specified (positive or negative) power. The order of evaluation of
5803 multiplications is not defined. When a vector of floating point type is
5804 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5805
5806<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5807<p>The second argument is an integer power, and the first is a value to raise to
5808 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5809
5810<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5811<p>This function returns the first value raised to the second power with an
5812 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5813
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5814</div>
5815
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5816<!-- _______________________________________________________________________ -->
5817<div class="doc_subsubsection">
5818 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5819</div>
5820
5821<div class="doc_text">
5822
5823<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5824<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5825 floating point or vector of floating point type. Not all targets support all
5826 types however.</p>
5827
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5828<pre>
5829 declare float @llvm.sin.f32(float %Val)
5830 declare double @llvm.sin.f64(double %Val)
5831 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5832 declare fp128 @llvm.sin.f128(fp128 %Val)
5833 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5834</pre>
5835
5836<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5837<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5838
5839<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5840<p>The argument and return value are floating point numbers of the same
5841 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5842
5843<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5844<p>This function returns the sine of the specified operand, returning the same
5845 values as the libm <tt>sin</tt> functions would, and handles error conditions
5846 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5847
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5848</div>
5849
5850<!-- _______________________________________________________________________ -->
5851<div class="doc_subsubsection">
5852 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5853</div>
5854
5855<div class="doc_text">
5856
5857<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5858<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5859 floating point or vector of floating point type. Not all targets support all
5860 types however.</p>
5861
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5862<pre>
5863 declare float @llvm.cos.f32(float %Val)
5864 declare double @llvm.cos.f64(double %Val)
5865 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5866 declare fp128 @llvm.cos.f128(fp128 %Val)
5867 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5868</pre>
5869
5870<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5871<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5872
5873<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5874<p>The argument and return value are floating point numbers of the same
5875 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5876
5877<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5878<p>This function returns the cosine of the specified operand, returning the same
5879 values as the libm <tt>cos</tt> functions would, and handles error conditions
5880 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5881
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5882</div>
5883
5884<!-- _______________________________________________________________________ -->
5885<div class="doc_subsubsection">
5886 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5887</div>
5888
5889<div class="doc_text">
5890
5891<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5892<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5893 floating point or vector of floating point type. Not all targets support all
5894 types however.</p>
5895
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5896<pre>
5897 declare float @llvm.pow.f32(float %Val, float %Power)
5898 declare double @llvm.pow.f64(double %Val, double %Power)
5899 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5900 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5901 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5902</pre>
5903
5904<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5905<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5906 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5907
5908<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5909<p>The second argument is a floating point power, and the first is a value to
5910 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5911
5912<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5913<p>This function returns the first value raised to the second power, returning
5914 the same values as the libm <tt>pow</tt> functions would, and handles error
5915 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5916
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5917</div>
5918
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5919<!-- ======================================================================= -->
5920<div class="doc_subsection">
5921 <a name="int_manip">Bit Manipulation Intrinsics</a>
5922</div>
5923
5924<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5925
5926<p>LLVM provides intrinsics for a few important bit manipulation operations.
5927 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5928
5929</div>
5930
5931<!-- _______________________________________________________________________ -->
5932<div class="doc_subsubsection">
5933 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5934</div>
5935
5936<div class="doc_text">
5937
5938<h5>Syntax:</h5>
5939<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5940 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5941
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5942<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5943 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5944 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5945 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5946</pre>
5947
5948<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5949<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5950 values with an even number of bytes (positive multiple of 16 bits). These
5951 are useful for performing operations on data that is not in the target's
5952 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5953
5954<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5955<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
5956 and low byte of the input i16 swapped. Similarly,
5957 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
5958 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
5959 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
5960 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
5961 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
5962 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5963
5964</div>
5965
5966<!-- _______________________________________________________________________ -->
5967<div class="doc_subsubsection">
5968 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5969</div>
5970
5971<div class="doc_text">
5972
5973<h5>Syntax:</h5>
5974<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]5975 width. Not all targets support all bit widths however.</p>
5976
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5977<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5978 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5979 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5980 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5981 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5982 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5983</pre>
5984
5985<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5986<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
5987 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5988
5989<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5990<p>The only argument is the value to be counted. The argument may be of any
5991 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5992
5993<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5994<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]5995
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5996</div>
5997
5998<!-- _______________________________________________________________________ -->
5999<div class="doc_subsubsection">
6000 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6001</div>
6002
6003<div class="doc_text">
6004
6005<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6006<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6007 integer bit width. Not all targets support all bit widths however.</p>
6008
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6009<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6010 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6011 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6012 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6013 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6014 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6015</pre>
6016
6017<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6018<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6019 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6020
6021<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6022<p>The only argument is the value to be counted. The argument may be of any
6023 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6024
6025<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6026<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6027 zeros in a variable. If the src == 0 then the result is the size in bits of
6028 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6029
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6030</div>
6031
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6032<!-- _______________________________________________________________________ -->
6033<div class="doc_subsubsection">
6034 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6035</div>
6036
6037<div class="doc_text">
6038
6039<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6040<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6041 integer bit width. Not all targets support all bit widths however.</p>
6042
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6043<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6044 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6045 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6046 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6047 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6048 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6049</pre>
6050
6051<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6052<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6053 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6054
6055<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6056<p>The only argument is the value to be counted. The argument may be of any
6057 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6058
6059<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6060<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6061 zeros in a variable. If the src == 0 then the result is the size in bits of
6062 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6063
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6064</div>
6065
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6066<!-- ======================================================================= -->
6067<div class="doc_subsection">
6068 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6069</div>
6070
6071<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6072
6073<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6074
6075</div>
6076
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6077<!-- _______________________________________________________________________ -->
6078<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6079 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6080</div>
6081
6082<div class="doc_text">
6083
6084<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6085<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]6086 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6087
6088<pre>
6089 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6090 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6091 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6092</pre>
6093
6094<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6095<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6096 a signed addition of the two arguments, and indicate whether an overflow
6097 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6098
6099<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6100<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]6101 be of integer types of any bit width, but they must have the same bit
6102 width. The second element of the result structure must be of
6103 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6104 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6105
6106<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6107<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6108 a signed addition of the two variables. They return a structure &mdash; the
6109 first element of which is the signed summation, and the second element of
6110 which is a bit specifying if the signed summation resulted in an
6111 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6112
6113<h5>Examples:</h5>
6114<pre>
6115 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6116 %sum = extractvalue {i32, i1} %res, 0
6117 %obit = extractvalue {i32, i1} %res, 1
6118 br i1 %obit, label %overflow, label %normal
6119</pre>
6120
6121</div>
6122
6123<!-- _______________________________________________________________________ -->
6124<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6125 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6126</div>
6127
6128<div class="doc_text">
6129
6130<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6131<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]6132 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6133
6134<pre>
6135 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6136 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6137 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6138</pre>
6139
6140<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6141<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6142 an unsigned addition of the two arguments, and indicate whether a carry
6143 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6144
6145<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6146<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]6147 be of integer types of any bit width, but they must have the same bit
6148 width. The second element of the result structure must be of
6149 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6150 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6151
6152<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6153<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6154 an unsigned addition of the two arguments. They return a structure &mdash;
6155 the first element of which is the sum, and the second element of which is a
6156 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6157
6158<h5>Examples:</h5>
6159<pre>
6160 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6161 %sum = extractvalue {i32, i1} %res, 0
6162 %obit = extractvalue {i32, i1} %res, 1
6163 br i1 %obit, label %carry, label %normal
6164</pre>
6165
6166</div>
6167
6168<!-- _______________________________________________________________________ -->
6169<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6170 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6171</div>
6172
6173<div class="doc_text">
6174
6175<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6176<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]6177 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6178
6179<pre>
6180 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6181 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6182 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6183</pre>
6184
6185<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6186<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6187 a signed subtraction of the two arguments, and indicate whether an overflow
6188 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6189
6190<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6191<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]6192 be of integer types of any bit width, but they must have the same bit
6193 width. The second element of the result structure must be of
6194 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6195 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6196
6197<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6198<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6199 a signed subtraction of the two arguments. They return a structure &mdash;
6200 the first element of which is the subtraction, and the second element of
6201 which is a bit specifying if the signed subtraction resulted in an
6202 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6203
6204<h5>Examples:</h5>
6205<pre>
6206 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6207 %sum = extractvalue {i32, i1} %res, 0
6208 %obit = extractvalue {i32, i1} %res, 1
6209 br i1 %obit, label %overflow, label %normal
6210</pre>
6211
6212</div>
6213
6214<!-- _______________________________________________________________________ -->
6215<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6216 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6217</div>
6218
6219<div class="doc_text">
6220
6221<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6222<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]6223 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6224
6225<pre>
6226 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6227 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6228 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6229</pre>
6230
6231<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6232<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6233 an unsigned subtraction of the two arguments, and indicate whether an
6234 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6235
6236<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6237<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]6238 be of integer types of any bit width, but they must have the same bit
6239 width. The second element of the result structure must be of
6240 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6241 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6242
6243<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6244<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6245 an unsigned subtraction of the two arguments. They return a structure &mdash;
6246 the first element of which is the subtraction, and the second element of
6247 which is a bit specifying if the unsigned subtraction resulted in an
6248 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6249
6250<h5>Examples:</h5>
6251<pre>
6252 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6253 %sum = extractvalue {i32, i1} %res, 0
6254 %obit = extractvalue {i32, i1} %res, 1
6255 br i1 %obit, label %overflow, label %normal
6256</pre>
6257
6258</div>
6259
6260<!-- _______________________________________________________________________ -->
6261<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6262 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6263</div>
6264
6265<div class="doc_text">
6266
6267<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6268<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]6269 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6270
6271<pre>
6272 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6273 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6274 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6275</pre>
6276
6277<h5>Overview:</h5>
6278
6279<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6280 a signed multiplication of the two arguments, and indicate whether an
6281 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6282
6283<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6284<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]6285 be of integer types of any bit width, but they must have the same bit
6286 width. The second element of the result structure must be of
6287 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6288 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6289
6290<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6291<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6292 a signed multiplication of the two arguments. They return a structure &mdash;
6293 the first element of which is the multiplication, and the second element of
6294 which is a bit specifying if the signed multiplication resulted in an
6295 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6296
6297<h5>Examples:</h5>
6298<pre>
6299 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6300 %sum = extractvalue {i32, i1} %res, 0
6301 %obit = extractvalue {i32, i1} %res, 1
6302 br i1 %obit, label %overflow, label %normal
6303</pre>
6304
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6305</div>
6306
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6307<!-- _______________________________________________________________________ -->
6308<div class="doc_subsubsection">
6309 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6310</div>
6311
6312<div class="doc_text">
6313
6314<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6315<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]6316 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6317
6318<pre>
6319 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6320 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6321 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6322</pre>
6323
6324<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6325<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6326 a unsigned multiplication of the two arguments, and indicate whether an
6327 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6328
6329<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6330<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]6331 be of integer types of any bit width, but they must have the same bit
6332 width. The second element of the result structure must be of
6333 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6334 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6335
6336<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6337<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6338 an unsigned multiplication of the two arguments. They return a structure
6339 &mdash; the first element of which is the multiplication, and the second
6340 element of which is a bit specifying if the unsigned multiplication resulted
6341 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6342
6343<h5>Examples:</h5>
6344<pre>
6345 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6346 %sum = extractvalue {i32, i1} %res, 0
6347 %obit = extractvalue {i32, i1} %res, 1
6348 br i1 %obit, label %overflow, label %normal
6349</pre>
6350
6351</div>
6352
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6353<!-- ======================================================================= -->
6354<div class="doc_subsection">
6355 <a name="int_debugger">Debugger Intrinsics</a>
6356</div>
6357
6358<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6359
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6360<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6361 prefix), are described in
6362 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6363 Level Debugging</a> document.</p>
6364
6365</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6366
6367<!-- ======================================================================= -->
6368<div class="doc_subsection">
6369 <a name="int_eh">Exception Handling Intrinsics</a>
6370</div>
6371
6372<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6373
6374<p>The LLVM exception handling intrinsics (which all start with
6375 <tt>llvm.eh.</tt> prefix), are described in
6376 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6377 Handling</a> document.</p>
6378
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6379</div>
6380
6381<!-- ======================================================================= -->
6382<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6383 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6384</div>
6385
6386<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6387
6388<p>This intrinsic makes it possible to excise one parameter, marked with
6389 the <tt>nest</tt> attribute, from a function. The result is a callable
6390 function pointer lacking the nest parameter - the caller does not need to
6391 provide a value for it. Instead, the value to use is stored in advance in a
6392 "trampoline", a block of memory usually allocated on the stack, which also
6393 contains code to splice the nest value into the argument list. This is used
6394 to implement the GCC nested function address extension.</p>
6395
6396<p>For example, if the function is
6397 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6398 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6399 follows:</p>
6400
6401<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6402<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6403 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6404 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6405 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6406 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6407</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6408</div>
6409
6410<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6411 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6412
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6413</div>
6414
6415<!-- _______________________________________________________________________ -->
6416<div class="doc_subsubsection">
6417 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6418</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6419
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6420<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6421
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6422<h5>Syntax:</h5>
6423<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6424 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]6425</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6426
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6427<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6428<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6429 function pointer suitable for executing it.</p>
6430
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6431<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6432<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6433 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6434 sufficiently aligned block of memory; this memory is written to by the
6435 intrinsic. Note that the size and the alignment are target-specific - LLVM
6436 currently provides no portable way of determining them, so a front-end that
6437 generates this intrinsic needs to have some target-specific knowledge.
6438 The <tt>func</tt> argument must hold a function bitcast to
6439 an <tt>i8*</tt>.</p>
6440
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6441<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6442<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6443 dependent code, turning it into a function. A pointer to this function is
6444 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6445 function pointer type</a> before being called. The new function's signature
6446 is the same as that of <tt>func</tt> with any arguments marked with
6447 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6448 is allowed, and it must be of pointer type. Calling the new function is
6449 equivalent to calling <tt>func</tt> with the same argument list, but
6450 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6451 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6452 by <tt>tramp</tt> is modified, then the effect of any later call to the
6453 returned function pointer is undefined.</p>
6454
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6455</div>
6456
6457<!-- ======================================================================= -->
6458<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6459 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6460</div>
6461
6462<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6463
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6464<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6465 hardware constructs for atomic operations and memory synchronization. This
6466 provides an interface to the hardware, not an interface to the programmer. It
6467 is aimed at a low enough level to allow any programming models or APIs
6468 (Application Programming Interfaces) which need atomic behaviors to map
6469 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6470 hardware provides a "universal IR" for source languages, it also provides a
6471 starting point for developing a "universal" atomic operation and
6472 synchronization IR.</p>
6473
6474<p>These do <em>not</em> form an API such as high-level threading libraries,
6475 software transaction memory systems, atomic primitives, and intrinsic
6476 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6477 application libraries. The hardware interface provided by LLVM should allow
6478 a clean implementation of all of these APIs and parallel programming models.
6479 No one model or paradigm should be selected above others unless the hardware
6480 itself ubiquitously does so.</p>
6481
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6482</div>
6483
6484<!-- _______________________________________________________________________ -->
6485<div class="doc_subsubsection">
6486 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6487</div>
6488<div class="doc_text">
6489<h5>Syntax:</h5>
6490<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6491 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]6492</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6493
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6494<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6495<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6496 specific pairs of memory access types.</p>
6497
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6498<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6499<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6500 The first four arguments enables a specific barrier as listed below. The
6501 fith argument specifies that the barrier applies to io or device or uncached
6502 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6503
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6504<ul>
6505 <li><tt>ll</tt>: load-load barrier</li>
6506 <li><tt>ls</tt>: load-store barrier</li>
6507 <li><tt>sl</tt>: store-load barrier</li>
6508 <li><tt>ss</tt>: store-store barrier</li>
6509 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6510</ul>
6511
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6512<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6513<p>This intrinsic causes the system to enforce some ordering constraints upon
6514 the loads and stores of the program. This barrier does not
6515 indicate <em>when</em> any events will occur, it only enforces
6516 an <em>order</em> in which they occur. For any of the specified pairs of load
6517 and store operations (f.ex. load-load, or store-load), all of the first
6518 operations preceding the barrier will complete before any of the second
6519 operations succeeding the barrier begin. Specifically the semantics for each
6520 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6521
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6522<ul>
6523 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6524 after the barrier begins.</li>
6525 <li><tt>ls</tt>: All loads before the barrier must complete before any
6526 store after the barrier begins.</li>
6527 <li><tt>ss</tt>: All stores before the barrier must complete before any
6528 store after the barrier begins.</li>
6529 <li><tt>sl</tt>: All stores before the barrier must complete before any
6530 load after the barrier begins.</li>
6531</ul>
6532
6533<p>These semantics are applied with a logical "and" behavior when more than one
6534 is enabled in a single memory barrier intrinsic.</p>
6535
6536<p>Backends may implement stronger barriers than those requested when they do
6537 not support as fine grained a barrier as requested. Some architectures do
6538 not need all types of barriers and on such architectures, these become
6539 noops.</p>
6540
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6541<h5>Example:</h5>
6542<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6543%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6544%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6545 store i32 4, %ptr
6546
6547%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6548 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6549 <i>; guarantee the above finishes</i>
6550 store i32 8, %ptr <i>; before this begins</i>
6551</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6552
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6553</div>
6554
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6555<!-- _______________________________________________________________________ -->
6556<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6557 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6558</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6559
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6560<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6561
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6562<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6563<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6564 any integer bit width and for different address spaces. Not all targets
6565 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6566
6567<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6568 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6569 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6570 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6571 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]6572</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6573
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6574<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6575<p>This loads a value in memory and compares it to a given value. If they are
6576 equal, it stores a new value into the memory.</p>
6577
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6578<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6579<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6580 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6581 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6582 this integer type. While any bit width integer may be used, targets may only
6583 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6584
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6585<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6586<p>This entire intrinsic must be executed atomically. It first loads the value
6587 in memory pointed to by <tt>ptr</tt> and compares it with the
6588 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6589 memory. The loaded value is yielded in all cases. This provides the
6590 equivalent of an atomic compare-and-swap operation within the SSA
6591 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6592
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6593<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6594<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6595%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6596%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6597 store i32 4, %ptr
6598
6599%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6600%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6601 <i>; yields {i32}:result1 = 4</i>
6602%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6603%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6604
6605%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6606%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6607 <i>; yields {i32}:result2 = 8</i>
6608%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6609
6610%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6611</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6612
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6613</div>
6614
6615<!-- _______________________________________________________________________ -->
6616<div class="doc_subsubsection">
6617 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6618</div>
6619<div class="doc_text">
6620<h5>Syntax:</h5>
6621
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6622<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6623 integer bit width. Not all targets support all bit widths however.</p>
6624
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6625<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6626 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6627 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6628 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6629 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]6630</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6631
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6632<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6633<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6634 the value from memory. It then stores the value in <tt>val</tt> in the memory
6635 at <tt>ptr</tt>.</p>
6636
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6637<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6638<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6639 the <tt>val</tt> argument and the result must be integers of the same bit
6640 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6641 integer type. The targets may only lower integer representations they
6642 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6643
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6644<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6645<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6646 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6647 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6648
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6649<h5>Examples:</h5>
6650<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6651%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6652%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6653 store i32 4, %ptr
6654
6655%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6656%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6657 <i>; yields {i32}:result1 = 4</i>
6658%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6659%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6660
6661%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6662%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6663 <i>; yields {i32}:result2 = 8</i>
6664
6665%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6666%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6667</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6668
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6669</div>
6670
6671<!-- _______________________________________________________________________ -->
6672<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6673 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6674
6675</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6676
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6677<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6678
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6679<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6680<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6681 any integer bit width. Not all targets support all bit widths however.</p>
6682
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6683<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6684 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6685 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6686 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6687 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]6688</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6689
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6690<h5>Overview:</h5>
6691<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6692 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6693
6694<h5>Arguments:</h5>
6695<p>The intrinsic takes two arguments, the first a pointer to an integer value
6696 and the second an integer value. The result is also an integer value. These
6697 integer types can have any bit width, but they must all have the same bit
6698 width. The targets may only lower integer representations they support.</p>
6699
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6700<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6701<p>This intrinsic does a series of operations atomically. It first loads the
6702 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6703 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]6704
6705<h5>Examples:</h5>
6706<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6707%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6708%ptr = bitcast i8* %mallocP to i32*
6709 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6710%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6711 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6712%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6713 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6714%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6715 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6716%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6717</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6718
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6719</div>
6720
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6721<!-- _______________________________________________________________________ -->
6722<div class="doc_subsubsection">
6723 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6724
6725</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6726
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6727<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6728
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6729<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6730<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6731 any integer bit width and for different address spaces. Not all targets
6732 support all bit widths however.</p>
6733
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6734<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6735 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6736 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6737 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6738 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]6739</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6740
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6741<h5>Overview:</h5>
6742<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6743 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6744
6745<h5>Arguments:</h5>
6746<p>The intrinsic takes two arguments, the first a pointer to an integer value
6747 and the second an integer value. The result is also an integer value. These
6748 integer types can have any bit width, but they must all have the same bit
6749 width. The targets may only lower integer representations they support.</p>
6750
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6751<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6752<p>This intrinsic does a series of operations atomically. It first loads the
6753 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6754 result to <tt>ptr</tt>. It yields the original value stored
6755 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6756
6757<h5>Examples:</h5>
6758<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6759%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6760%ptr = bitcast i8* %mallocP to i32*
6761 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6762%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6763 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6764%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6765 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6766%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6767 <i>; yields {i32}:result3 = 2</i>
6768%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6769</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6770
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6771</div>
6772
6773<!-- _______________________________________________________________________ -->
6774<div class="doc_subsubsection">
6775 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6776 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6777 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6778 <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]6779</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6780
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6781<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6782
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6783<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6784<p>These are overloaded intrinsics. You can
6785 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6786 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6787 bit width and for different address spaces. Not all targets support all bit
6788 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6789
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6790<pre>
6791 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6792 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6793 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6794 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]6795</pre>
6796
6797<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6798 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6799 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6800 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6801 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]6802</pre>
6803
6804<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6805 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6806 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6807 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6808 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]6809</pre>
6810
6811<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6812 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6813 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6814 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6815 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]6816</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6817
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6818<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6819<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6820 the value stored in memory at <tt>ptr</tt>. It yields the original value
6821 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6822
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6823<h5>Arguments:</h5>
6824<p>These intrinsics take two arguments, the first a pointer to an integer value
6825 and the second an integer value. The result is also an integer value. These
6826 integer types can have any bit width, but they must all have the same bit
6827 width. The targets may only lower integer representations they support.</p>
6828
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6829<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6830<p>These intrinsics does a series of operations atomically. They first load the
6831 value stored at <tt>ptr</tt>. They then do the bitwise
6832 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6833 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6834
6835<h5>Examples:</h5>
6836<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6837%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6838%ptr = bitcast i8* %mallocP to i32*
6839 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6840%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6841 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6842%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6843 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6844%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6845 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6846%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6847 <i>; yields {i32}:result3 = FF</i>
6848%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6849</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6850
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6851</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6852
6853<!-- _______________________________________________________________________ -->
6854<div class="doc_subsubsection">
6855 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6856 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6857 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6858 <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]6859</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6860
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6861<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6862
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6863<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6864<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6865 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6866 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6867 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6868
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6869<pre>
6870 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6871 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6872 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6873 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]6874</pre>
6875
6876<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6877 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6878 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6879 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6880 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]6881</pre>
6882
6883<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6884 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6885 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6886 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6887 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]6888</pre>
6889
6890<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6891 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6892 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6893 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6894 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]6895</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6896
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6897<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6898<p>These intrinsics takes the signed or unsigned minimum or maximum of
6899 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6900 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6901
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6902<h5>Arguments:</h5>
6903<p>These intrinsics take two arguments, the first a pointer to an integer value
6904 and the second an integer value. The result is also an integer value. These
6905 integer types can have any bit width, but they must all have the same bit
6906 width. The targets may only lower integer representations they support.</p>
6907
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6908<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6909<p>These intrinsics does a series of operations atomically. They first load the
6910 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6911 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6912 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6913
6914<h5>Examples:</h5>
6915<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6916%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6917%ptr = bitcast i8* %mallocP to i32*
6918 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6919%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6920 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6921%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6922 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6923%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6924 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6925%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6926 <i>; yields {i32}:result3 = 8</i>
6927%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6928</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6929
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6930</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6931
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]6932
6933<!-- ======================================================================= -->
6934<div class="doc_subsection">
6935 <a name="int_memorymarkers">Memory Use Markers</a>
6936</div>
6937
6938<div class="doc_text">
6939
6940<p>This class of intrinsics exists to information about the lifetime of memory
6941 objects and ranges where variables are immutable.</p>
6942
6943</div>
6944
6945<!-- _______________________________________________________________________ -->
6946<div class="doc_subsubsection">
6947 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
6948</div>
6949
6950<div class="doc_text">
6951
6952<h5>Syntax:</h5>
6953<pre>
6954 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
6955</pre>
6956
6957<h5>Overview:</h5>
6958<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
6959 object's lifetime.</p>
6960
6961<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]6962<p>The first argument is a constant integer representing the size of the
6963 object, or -1 if it is variable sized. The second argument is a pointer to
6964 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]6965
6966<h5>Semantics:</h5>
6967<p>This intrinsic indicates that before this point in the code, the value of the
6968 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^]6969 never be used and has an undefined value. A load from the pointer that
6970 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]6971 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
6972
6973</div>
6974
6975<!-- _______________________________________________________________________ -->
6976<div class="doc_subsubsection">
6977 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
6978</div>
6979
6980<div class="doc_text">
6981
6982<h5>Syntax:</h5>
6983<pre>
6984 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
6985</pre>
6986
6987<h5>Overview:</h5>
6988<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
6989 object's lifetime.</p>
6990
6991<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]6992<p>The first argument is a constant integer representing the size of the
6993 object, or -1 if it is variable sized. The second argument is a pointer to
6994 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]6995
6996<h5>Semantics:</h5>
6997<p>This intrinsic indicates that after this point in the code, the value of the
6998 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
6999 never be used and has an undefined value. Any stores into the memory object
7000 following this intrinsic may be removed as dead.
7001
7002</div>
7003
7004<!-- _______________________________________________________________________ -->
7005<div class="doc_subsubsection">
7006 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7007</div>
7008
7009<div class="doc_text">
7010
7011<h5>Syntax:</h5>
7012<pre>
7013 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7014</pre>
7015
7016<h5>Overview:</h5>
7017<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7018 a memory object will not change.</p>
7019
7020<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7021<p>The first argument is a constant integer representing the size of the
7022 object, or -1 if it is variable sized. The second argument is a pointer to
7023 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7024
7025<h5>Semantics:</h5>
7026<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7027 the return value, the referenced memory location is constant and
7028 unchanging.</p>
7029
7030</div>
7031
7032<!-- _______________________________________________________________________ -->
7033<div class="doc_subsubsection">
7034 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7035</div>
7036
7037<div class="doc_text">
7038
7039<h5>Syntax:</h5>
7040<pre>
7041 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7042</pre>
7043
7044<h5>Overview:</h5>
7045<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7046 a memory object are mutable.</p>
7047
7048<h5>Arguments:</h5>
7049<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7050 The second argument is a constant integer representing the size of the
7051 object, or -1 if it is variable sized and the third argument is a pointer
7052 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7053
7054<h5>Semantics:</h5>
7055<p>This intrinsic indicates that the memory is mutable again.</p>
7056
7057</div>
7058
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7059<!-- ======================================================================= -->
7060<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7061 <a name="int_general">General Intrinsics</a>
7062</div>
7063
7064<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7065
7066<p>This class of intrinsics is designed to be generic and has no specific
7067 purpose.</p>
7068
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7069</div>
7070
7071<!-- _______________________________________________________________________ -->
7072<div class="doc_subsubsection">
7073 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7074</div>
7075
7076<div class="doc_text">
7077
7078<h5>Syntax:</h5>
7079<pre>
7080 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7081</pre>
7082
7083<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7084<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7085
7086<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7087<p>The first argument is a pointer to a value, the second is a pointer to a
7088 global string, the third is a pointer to a global string which is the source
7089 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7090
7091<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7092<p>This intrinsic allows annotation of local variables with arbitrary strings.
7093 This can be useful for special purpose optimizations that want to look for
7094 these annotations. These have no other defined use, they are ignored by code
7095 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7096
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7097</div>
7098
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7099<!-- _______________________________________________________________________ -->
7100<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7101 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7102</div>
7103
7104<div class="doc_text">
7105
7106<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7107<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7108 any integer bit width.</p>
7109
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7110<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7111 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7112 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7113 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7114 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7115 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]7116</pre>
7117
7118<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7119<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7120
7121<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7122<p>The first argument is an integer value (result of some expression), the
7123 second is a pointer to a global string, the third is a pointer to a global
7124 string which is the source file name, and the last argument is the line
7125 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7126
7127<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7128<p>This intrinsic allows annotations to be put on arbitrary expressions with
7129 arbitrary strings. This can be useful for special purpose optimizations that
7130 want to look for these annotations. These have no other defined use, they
7131 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7132
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7133</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7134
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7135<!-- _______________________________________________________________________ -->
7136<div class="doc_subsubsection">
7137 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7138</div>
7139
7140<div class="doc_text">
7141
7142<h5>Syntax:</h5>
7143<pre>
7144 declare void @llvm.trap()
7145</pre>
7146
7147<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7148<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7149
7150<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7151<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7152
7153<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7154<p>This intrinsics is lowered to the target dependent trap instruction. If the
7155 target does not have a trap instruction, this intrinsic will be lowered to
7156 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7157
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7158</div>
7159
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7160<!-- _______________________________________________________________________ -->
7161<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7162 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7163</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7164
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7165<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7166
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7167<h5>Syntax:</h5>
7168<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7169 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7170</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7171
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7172<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7173<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7174 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7175 ensure that it is placed on the stack before local variables.</p>
7176
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7177<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7178<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7179 arguments. The first argument is the value loaded from the stack
7180 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7181 that has enough space to hold the value of the guard.</p>
7182
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7183<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7184<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7185 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7186 stack. This is to ensure that if a local variable on the stack is
7187 overwritten, it will destroy the value of the guard. When the function exits,
7188 the guard on the stack is checked against the original guard. If they're
7189 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7190 function.</p>
7191
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7192</div>
7193
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7194<!-- *********************************************************************** -->
7195<hr>
7196<address>
7197 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7198 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7199 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7200 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]7201
7202 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7203 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7204 Last modified: $Date$
7205</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7206
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7207</body>
7208</html>