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5 <title>LLVM Assembly Language Reference Manual</title>
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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 +000023 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendlinge2753242009-07-20 02:41:50 +000025 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
27 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
28 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
29 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
30 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
31 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
32 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
33 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_linkonce">'<tt>linkonce_odr</tt>' Linkage</a></li>
35 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
36 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
37 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +000039 </ol>
40 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000041 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +000042 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000043 <li><a href="#globalvars">Global Variables</a></li>
44 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +000045 <li><a href="#aliasstructure">Aliases</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000046 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +000047 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +000048 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000049 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
50 <li><a href="#datalayout">Data Layout</a></li>
51 </ol>
52 </li>
53 <li><a href="#typesystem">Type System</a>
54 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +000055 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000056 <li><a href="#t_primitive">Primitive Types</a>
57 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +000058 <li><a href="#t_floating">Floating Point Types</a></li>
59 <li><a href="#t_void">Void Type</a></li>
60 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +000061 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000062 </ol>
63 </li>
64 <li><a href="#t_derived">Derived Types</a>
65 <ol>
Chris Lattner251ab812007-12-18 06:18:21 +000066 <li><a href="#t_integer">Integer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000067 <li><a href="#t_array">Array Type</a></li>
68 <li><a href="#t_function">Function Type</a></li>
69 <li><a href="#t_pointer">Pointer Type</a></li>
70 <li><a href="#t_struct">Structure Type</a></li>
71 <li><a href="#t_pstruct">Packed Structure Type</a></li>
72 <li><a href="#t_vector">Vector Type</a></li>
73 <li><a href="#t_opaque">Opaque Type</a></li>
74 </ol>
75 </li>
Chris Lattner515195a2009-02-02 07:32:36 +000076 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000077 </ol>
78 </li>
79 <li><a href="#constants">Constants</a>
80 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +000081 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +000082 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +000083 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
84 <li><a href="#undefvalues">Undefined Values</a></li>
85 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky4dcf8102009-04-04 07:22:01 +000086 <li><a href="#metadata">Embedded Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000087 </ol>
88 </li>
89 <li><a href="#othervalues">Other Values</a>
90 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +000091 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000092 </ol>
93 </li>
Chris Lattner75c24e02009-07-20 05:55:19 +000094 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
95 <ol>
96 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner1e0e0d12009-07-20 06:14:25 +000097 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
98 Global Variable</a></li>
Chris Lattner75c24e02009-07-20 05:55:19 +000099 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
100 Global Variable</a></li>
101 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
102 Global Variable</a></li>
103 </ol>
104 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000105 <li><a href="#instref">Instruction Reference</a>
106 <ol>
107 <li><a href="#terminators">Terminator Instructions</a>
108 <ol>
109 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
110 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
111 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
112 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
113 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
114 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
115 </ol>
116 </li>
117 <li><a href="#binaryops">Binary Operations</a>
118 <ol>
119 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000120 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000121 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000122 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000123 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000124 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000125 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
126 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
127 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
128 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
129 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
130 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
131 </ol>
132 </li>
133 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
134 <ol>
135 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
136 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
137 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
138 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
139 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
140 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
141 </ol>
142 </li>
143 <li><a href="#vectorops">Vector Operations</a>
144 <ol>
145 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
146 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
147 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
148 </ol>
149 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000150 <li><a href="#aggregateops">Aggregate Operations</a>
151 <ol>
152 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
153 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
154 </ol>
155 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000156 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
157 <ol>
158 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
159 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
160 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
161 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
162 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
163 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
164 </ol>
165 </li>
166 <li><a href="#convertops">Conversion Operations</a>
167 <ol>
168 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
169 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
170 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
171 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
172 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
173 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
174 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
175 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
176 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
177 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
178 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
179 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
180 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000181 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000182 <li><a href="#otherops">Other Operations</a>
183 <ol>
184 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
185 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
186 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
187 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
188 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
189 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
190 </ol>
191 </li>
192 </ol>
193 </li>
194 <li><a href="#intrinsics">Intrinsic Functions</a>
195 <ol>
196 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
197 <ol>
198 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
199 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
200 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
201 </ol>
202 </li>
203 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
204 <ol>
205 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
206 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
207 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
208 </ol>
209 </li>
210 <li><a href="#int_codegen">Code Generator Intrinsics</a>
211 <ol>
212 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
213 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
214 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
215 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
216 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
217 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
218 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
219 </ol>
220 </li>
221 <li><a href="#int_libc">Standard C Library Intrinsics</a>
222 <ol>
223 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
224 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
225 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
226 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
227 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000228 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
229 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
230 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000231 </ol>
232 </li>
233 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
234 <ol>
235 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
236 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
237 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
238 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000239 </ol>
240 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000241 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
242 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000243 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
244 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
245 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
246 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
247 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000248 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000249 </ol>
250 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000251 <li><a href="#int_debugger">Debugger intrinsics</a></li>
252 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000253 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000254 <ol>
255 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000256 </ol>
257 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000258 <li><a href="#int_atomics">Atomic intrinsics</a>
259 <ol>
260 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
261 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
262 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
263 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
264 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
265 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
266 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
267 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
268 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
269 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
270 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
271 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
272 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
273 </ol>
274 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000275 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000276 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000277 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000278 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000279 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000280 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000281 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000282 '<tt>llvm.trap</tt>' Intrinsic</a></li>
283 <li><a href="#int_stackprotector">
284 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000285 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000286 </li>
287 </ol>
288 </li>
289</ol>
290
291<div class="doc_author">
292 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
293 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
294</div>
295
296<!-- *********************************************************************** -->
297<div class="doc_section"> <a name="abstract">Abstract </a></div>
298<!-- *********************************************************************** -->
299
300<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000301
302<p>This document is a reference manual for the LLVM assembly language. LLVM is
303 a Static Single Assignment (SSA) based representation that provides type
304 safety, low-level operations, flexibility, and the capability of representing
305 'all' high-level languages cleanly. It is the common code representation
306 used throughout all phases of the LLVM compilation strategy.</p>
307
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000308</div>
309
310<!-- *********************************************************************** -->
311<div class="doc_section"> <a name="introduction">Introduction</a> </div>
312<!-- *********************************************************************** -->
313
314<div class="doc_text">
315
Bill Wendlingf85859d2009-07-20 02:29:24 +0000316<p>The LLVM code representation is designed to be used in three different forms:
317 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
318 for fast loading by a Just-In-Time compiler), and as a human readable
319 assembly language representation. This allows LLVM to provide a powerful
320 intermediate representation for efficient compiler transformations and
321 analysis, while providing a natural means to debug and visualize the
322 transformations. The three different forms of LLVM are all equivalent. This
323 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000324
Bill Wendlingf85859d2009-07-20 02:29:24 +0000325<p>The LLVM representation aims to be light-weight and low-level while being
326 expressive, typed, and extensible at the same time. It aims to be a
327 "universal IR" of sorts, by being at a low enough level that high-level ideas
328 may be cleanly mapped to it (similar to how microprocessors are "universal
329 IR's", allowing many source languages to be mapped to them). By providing
330 type information, LLVM can be used as the target of optimizations: for
331 example, through pointer analysis, it can be proven that a C automatic
332 variable is never accessed outside of the current function... allowing it to
333 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000334
335</div>
336
337<!-- _______________________________________________________________________ -->
338<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
339
340<div class="doc_text">
341
Bill Wendlingf85859d2009-07-20 02:29:24 +0000342<p>It is important to note that this document describes 'well formed' LLVM
343 assembly language. There is a difference between what the parser accepts and
344 what is considered 'well formed'. For example, the following instruction is
345 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000346
347<div class="doc_code">
348<pre>
349%x = <a href="#i_add">add</a> i32 1, %x
350</pre>
351</div>
352
Bill Wendlingf85859d2009-07-20 02:29:24 +0000353<p>...because the definition of <tt>%x</tt> does not dominate all of its
354 uses. The LLVM infrastructure provides a verification pass that may be used
355 to verify that an LLVM module is well formed. This pass is automatically run
356 by the parser after parsing input assembly and by the optimizer before it
357 outputs bitcode. The violations pointed out by the verifier pass indicate
358 bugs in transformation passes or input to the parser.</p>
359
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000360</div>
361
Chris Lattnera83fdc02007-10-03 17:34:29 +0000362<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000363
364<!-- *********************************************************************** -->
365<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
366<!-- *********************************************************************** -->
367
368<div class="doc_text">
369
Bill Wendlingf85859d2009-07-20 02:29:24 +0000370<p>LLVM identifiers come in two basic types: global and local. Global
371 identifiers (functions, global variables) begin with the <tt>'@'</tt>
372 character. Local identifiers (register names, types) begin with
373 the <tt>'%'</tt> character. Additionally, there are three different formats
374 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000375
376<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000377 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000378 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
379 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
380 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
381 other characters in their names can be surrounded with quotes. Special
382 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
383 ASCII code for the character in hexadecimal. In this way, any character
384 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000385
Reid Spencerc8245b02007-08-07 14:34:28 +0000386 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000387 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000388
389 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000390 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000391</ol>
392
Reid Spencerc8245b02007-08-07 14:34:28 +0000393<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000394 don't need to worry about name clashes with reserved words, and the set of
395 reserved words may be expanded in the future without penalty. Additionally,
396 unnamed identifiers allow a compiler to quickly come up with a temporary
397 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000398
399<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000400 languages. There are keywords for different opcodes
401 ('<tt><a href="#i_add">add</a></tt>',
402 '<tt><a href="#i_bitcast">bitcast</a></tt>',
403 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
404 ('<tt><a href="#t_void">void</a></tt>',
405 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
406 reserved words cannot conflict with variable names, because none of them
407 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000408
409<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000410 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000411
412<p>The easy way:</p>
413
414<div class="doc_code">
415<pre>
416%result = <a href="#i_mul">mul</a> i32 %X, 8
417</pre>
418</div>
419
420<p>After strength reduction:</p>
421
422<div class="doc_code">
423<pre>
424%result = <a href="#i_shl">shl</a> i32 %X, i8 3
425</pre>
426</div>
427
428<p>And the hard way:</p>
429
430<div class="doc_code">
431<pre>
432<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
433<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
434%result = <a href="#i_add">add</a> i32 %1, %1
435</pre>
436</div>
437
Bill Wendlingf85859d2009-07-20 02:29:24 +0000438<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
439 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000440
441<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000442 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000443 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000444
445 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000446 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000447
448 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000449</ol>
450
451<p>...and it also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000452 demonstrating instructions, we will follow an instruction with a comment that
453 defines the type and name of value produced. Comments are shown in italic
454 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000455
456</div>
457
458<!-- *********************************************************************** -->
459<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
460<!-- *********************************************************************** -->
461
462<!-- ======================================================================= -->
463<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
464</div>
465
466<div class="doc_text">
467
Bill Wendlingf85859d2009-07-20 02:29:24 +0000468<p>LLVM programs are composed of "Module"s, each of which is a translation unit
469 of the input programs. Each module consists of functions, global variables,
470 and symbol table entries. Modules may be combined together with the LLVM
471 linker, which merges function (and global variable) definitions, resolves
472 forward declarations, and merges symbol table entries. Here is an example of
473 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000474
475<div class="doc_code">
476<pre><i>; Declare the string constant as a global constant...</i>
477<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
478 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
479
480<i>; External declaration of the puts function</i>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000481<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000482
483<i>; Definition of main function</i>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000484define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000485 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000486 %cast210 = <a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000487 href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000488
489 <i>; Call puts function to write out the string to stdout...</i>
490 <a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000491 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000492 <a
493 href="#i_ret">ret</a> i32 0<br>}<br>
494</pre>
495</div>
496
Bill Wendlingf85859d2009-07-20 02:29:24 +0000497<p>This example is made up of a <a href="#globalvars">global variable</a> named
498 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
499 a <a href="#functionstructure">function definition</a> for
500 "<tt>main</tt>".</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000501
Bill Wendlingf85859d2009-07-20 02:29:24 +0000502<p>In general, a module is made up of a list of global values, where both
503 functions and global variables are global values. Global values are
504 represented by a pointer to a memory location (in this case, a pointer to an
505 array of char, and a pointer to a function), and have one of the
506 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000507
508</div>
509
510<!-- ======================================================================= -->
511<div class="doc_subsection">
512 <a name="linkage">Linkage Types</a>
513</div>
514
515<div class="doc_text">
516
Bill Wendlingf85859d2009-07-20 02:29:24 +0000517<p>All Global Variables and Functions have one of the following types of
518 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000519
520<dl>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000521 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000522 <dd>Global values with private linkage are only directly accessible by objects
523 in the current module. In particular, linking code into a module with an
524 private global value may cause the private to be renamed as necessary to
525 avoid collisions. Because the symbol is private to the module, all
526 references can be updated. This doesn't show up in any symbol table in the
527 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000528
Bill Wendling41a07852009-07-20 01:03:30 +0000529 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt>: </dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000530 <dd>Similar to private, but the symbol is passed through the assembler and
531 removed by the linker after evaluation.</dd>
532
Dale Johannesen96e7e092008-05-23 23:13:41 +0000533 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000534 <dd>Similar to private, but the value shows as a local symbol
535 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
536 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000537
Bill Wendlingf85859d2009-07-20 02:29:24 +0000538 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner68433442009-04-13 05:44:34 +0000539 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000540 into the object file corresponding to the LLVM module. They exist to
541 allow inlining and other optimizations to take place given knowledge of
542 the definition of the global, which is known to be somewhere outside the
543 module. Globals with <tt>available_externally</tt> linkage are allowed to
544 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
545 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000546
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000547 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000548 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000549 the same name when linkage occurs. This is typically used to implement
550 inline functions, templates, or other code which must be generated in each
551 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
552 allowed to be discarded.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000553
Dale Johannesen96e7e092008-05-23 23:13:41 +0000554 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000555 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
556 linkage, except that unreferenced <tt>common</tt> globals may not be
557 discarded. This is used for globals that may be emitted in multiple
558 translation units, but that are not guaranteed to be emitted into every
559 translation unit that uses them. One example of this is tentative
560 definitions in C, such as "<tt>int X;</tt>" at global scope.</dd>
Dale Johannesen96e7e092008-05-23 23:13:41 +0000561
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000562 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Dale Johannesen96e7e092008-05-23 23:13:41 +0000563 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
Bill Wendlingf85859d2009-07-20 02:29:24 +0000564 that some targets may choose to emit different assembly sequences for them
565 for target-dependent reasons. This is used for globals that are declared
566 "weak" in C source code.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000567
568 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000569 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000570 pointer to array type. When two global variables with appending linkage
571 are linked together, the two global arrays are appended together. This is
572 the LLVM, typesafe, equivalent of having the system linker append together
573 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000574
575 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000576 <dd>The semantics of this linkage follow the ELF object file model: the symbol
577 is weak until linked, if not linked, the symbol becomes null instead of
578 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000579
Duncan Sands19d161f2009-03-07 15:45:40 +0000580 <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
Duncan Sands19d161f2009-03-07 15:45:40 +0000581 <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000582 <dd>Some languages allow differing globals to be merged, such as two functions
583 with different semantics. Other languages, such as <tt>C++</tt>, ensure
584 that only equivalent globals are ever merged (the "one definition rule" -
585 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
586 and <tt>weak_odr</tt> linkage types to indicate that the global will only
587 be merged with equivalent globals. These linkage types are otherwise the
588 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000590 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000591 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000592 visible, meaning that it participates in linkage and can be used to
593 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000594</dl>
595
Bill Wendlingf85859d2009-07-20 02:29:24 +0000596<p>The next two types of linkage are targeted for Microsoft Windows platform
597 only. They are designed to support importing (exporting) symbols from (to)
598 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000599
Bill Wendlingf85859d2009-07-20 02:29:24 +0000600<dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000601 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000602 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000603 or variable via a global pointer to a pointer that is set up by the DLL
604 exporting the symbol. On Microsoft Windows targets, the pointer name is
605 formed by combining <code>__imp_</code> and the function or variable
606 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000607
608 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000609 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000610 pointer to a pointer in a DLL, so that it can be referenced with the
611 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
612 name is formed by combining <code>__imp_</code> and the function or
613 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000614</dl>
615
Bill Wendlingf85859d2009-07-20 02:29:24 +0000616<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
617 another module defined a "<tt>.LC0</tt>" variable and was linked with this
618 one, one of the two would be renamed, preventing a collision. Since
619 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
620 declarations), they are accessible outside of the current module.</p>
621
622<p>It is illegal for a function <i>declaration</i> to have any linkage type
623 other than "externally visible", <tt>dllimport</tt>
624 or <tt>extern_weak</tt>.</p>
625
Duncan Sands19d161f2009-03-07 15:45:40 +0000626<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000627 or <tt>weak_odr</tt> linkages.</p>
628
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000629</div>
630
631<!-- ======================================================================= -->
632<div class="doc_subsection">
633 <a name="callingconv">Calling Conventions</a>
634</div>
635
636<div class="doc_text">
637
638<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000639 and <a href="#i_invoke">invokes</a> can all have an optional calling
640 convention specified for the call. The calling convention of any pair of
641 dynamic caller/callee must match, or the behavior of the program is
642 undefined. The following calling conventions are supported by LLVM, and more
643 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000644
645<dl>
646 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000647 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000648 specified) matches the target C calling conventions. This calling
649 convention supports varargs function calls and tolerates some mismatch in
650 the declared prototype and implemented declaration of the function (as
651 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000652
653 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000654 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000655 (e.g. by passing things in registers). This calling convention allows the
656 target to use whatever tricks it wants to produce fast code for the
657 target, without having to conform to an externally specified ABI
658 (Application Binary Interface). Implementations of this convention should
659 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
660 optimization</a> to be supported. This calling convention does not
661 support varargs and requires the prototype of all callees to exactly match
662 the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000663
664 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000665 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000666 as possible under the assumption that the call is not commonly executed.
667 As such, these calls often preserve all registers so that the call does
668 not break any live ranges in the caller side. This calling convention
669 does not support varargs and requires the prototype of all callees to
670 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000671
672 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000673 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000674 target-specific calling conventions to be used. Target specific calling
675 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000676</dl>
677
678<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000679 support Pascal conventions or any other well-known target-independent
680 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000681
682</div>
683
684<!-- ======================================================================= -->
685<div class="doc_subsection">
686 <a name="visibility">Visibility Styles</a>
687</div>
688
689<div class="doc_text">
690
Bill Wendlingf85859d2009-07-20 02:29:24 +0000691<p>All Global Variables and Functions have one of the following visibility
692 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000693
694<dl>
695 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000696 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000697 that the declaration is visible to other modules and, in shared libraries,
698 means that the declared entity may be overridden. On Darwin, default
699 visibility means that the declaration is visible to other modules. Default
700 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000701
702 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000703 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000704 object if they are in the same shared object. Usually, hidden visibility
705 indicates that the symbol will not be placed into the dynamic symbol
706 table, so no other module (executable or shared library) can reference it
707 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000708
709 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000710 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000711 the dynamic symbol table, but that references within the defining module
712 will bind to the local symbol. That is, the symbol cannot be overridden by
713 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000714</dl>
715
716</div>
717
718<!-- ======================================================================= -->
719<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000720 <a name="namedtypes">Named Types</a>
721</div>
722
723<div class="doc_text">
724
725<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingf85859d2009-07-20 02:29:24 +0000726 it easier to read the IR and make the IR more condensed (particularly when
727 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000728
729<div class="doc_code">
730<pre>
731%mytype = type { %mytype*, i32 }
732</pre>
733</div>
734
Bill Wendlingf85859d2009-07-20 02:29:24 +0000735<p>You may give a name to any <a href="#typesystem">type</a> except
736 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
737 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000738
739<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000740 and that you can therefore specify multiple names for the same type. This
741 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
742 uses structural typing, the name is not part of the type. When printing out
743 LLVM IR, the printer will pick <em>one name</em> to render all types of a
744 particular shape. This means that if you have code where two different
745 source types end up having the same LLVM type, that the dumper will sometimes
746 print the "wrong" or unexpected type. This is an important design point and
747 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000748
749</div>
750
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000751<!-- ======================================================================= -->
752<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000753 <a name="globalvars">Global Variables</a>
754</div>
755
756<div class="doc_text">
757
758<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000759 instead of run-time. Global variables may optionally be initialized, may
760 have an explicit section to be placed in, and may have an optional explicit
761 alignment specified. A variable may be defined as "thread_local", which
762 means that it will not be shared by threads (each thread will have a
763 separated copy of the variable). A variable may be defined as a global
764 "constant," which indicates that the contents of the variable
765 will <b>never</b> be modified (enabling better optimization, allowing the
766 global data to be placed in the read-only section of an executable, etc).
767 Note that variables that need runtime initialization cannot be marked
768 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000769
Bill Wendlingf85859d2009-07-20 02:29:24 +0000770<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
771 constant, even if the final definition of the global is not. This capability
772 can be used to enable slightly better optimization of the program, but
773 requires the language definition to guarantee that optimizations based on the
774 'constantness' are valid for the translation units that do not include the
775 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000776
Bill Wendlingf85859d2009-07-20 02:29:24 +0000777<p>As SSA values, global variables define pointer values that are in scope
778 (i.e. they dominate) all basic blocks in the program. Global variables
779 always define a pointer to their "content" type because they describe a
780 region of memory, and all memory objects in LLVM are accessed through
781 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000782
Bill Wendlingf85859d2009-07-20 02:29:24 +0000783<p>A global variable may be declared to reside in a target-specific numbered
784 address space. For targets that support them, address spaces may affect how
785 optimizations are performed and/or what target instructions are used to
786 access the variable. The default address space is zero. The address space
787 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000788
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000789<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000790 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000791
792<p>An explicit alignment may be specified for a global. If not present, or if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000793 the alignment is set to zero, the alignment of the global is set by the
794 target to whatever it feels convenient. If an explicit alignment is
795 specified, the global is forced to have at least that much alignment. All
796 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000797
Bill Wendlingf85859d2009-07-20 02:29:24 +0000798<p>For example, the following defines a global in a numbered address space with
799 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000800
801<div class="doc_code">
802<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000803@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000804</pre>
805</div>
806
807</div>
808
809
810<!-- ======================================================================= -->
811<div class="doc_subsection">
812 <a name="functionstructure">Functions</a>
813</div>
814
815<div class="doc_text">
816
Bill Wendlingf85859d2009-07-20 02:29:24 +0000817<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
818 optional <a href="#linkage">linkage type</a>, an optional
819 <a href="#visibility">visibility style</a>, an optional
820 <a href="#callingconv">calling convention</a>, a return type, an optional
821 <a href="#paramattrs">parameter attribute</a> for the return type, a function
822 name, a (possibly empty) argument list (each with optional
823 <a href="#paramattrs">parameter attributes</a>), optional
824 <a href="#fnattrs">function attributes</a>, an optional section, an optional
825 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
826 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000827
Bill Wendlingf85859d2009-07-20 02:29:24 +0000828<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
829 optional <a href="#linkage">linkage type</a>, an optional
830 <a href="#visibility">visibility style</a>, an optional
831 <a href="#callingconv">calling convention</a>, a return type, an optional
832 <a href="#paramattrs">parameter attribute</a> for the return type, a function
833 name, a possibly empty list of arguments, an optional alignment, and an
834 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000835
Chris Lattner96451482008-08-05 18:29:16 +0000836<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000837 (Control Flow Graph) for the function. Each basic block may optionally start
838 with a label (giving the basic block a symbol table entry), contains a list
839 of instructions, and ends with a <a href="#terminators">terminator</a>
840 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000841
842<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlingf85859d2009-07-20 02:29:24 +0000843 executed on entrance to the function, and it is not allowed to have
844 predecessor basic blocks (i.e. there can not be any branches to the entry
845 block of a function). Because the block can have no predecessors, it also
846 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000847
848<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000849 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000850
851<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000852 the alignment is set to zero, the alignment of the function is set by the
853 target to whatever it feels convenient. If an explicit alignment is
854 specified, the function is forced to have at least that much alignment. All
855 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000856
Bill Wendling6ec40612009-07-20 02:39:26 +0000857<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000858<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000859<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000860define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000861 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
862 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
863 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
864 [<a href="#gc">gc</a>] { ... }
865</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000866</div>
867
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000868</div>
869
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000870<!-- ======================================================================= -->
871<div class="doc_subsection">
872 <a name="aliasstructure">Aliases</a>
873</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000874
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000875<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000876
877<p>Aliases act as "second name" for the aliasee value (which can be either
878 function, global variable, another alias or bitcast of global value). Aliases
879 may have an optional <a href="#linkage">linkage type</a>, and an
880 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000881
Bill Wendling6ec40612009-07-20 02:39:26 +0000882<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000883<div class="doc_code">
884<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000885@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000886</pre>
887</div>
888
889</div>
890
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000891<!-- ======================================================================= -->
892<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000893
Bill Wendlingf85859d2009-07-20 02:29:24 +0000894<div class="doc_text">
895
896<p>The return type and each parameter of a function type may have a set of
897 <i>parameter attributes</i> associated with them. Parameter attributes are
898 used to communicate additional information about the result or parameters of
899 a function. Parameter attributes are considered to be part of the function,
900 not of the function type, so functions with different parameter attributes
901 can have the same function type.</p>
902
903<p>Parameter attributes are simple keywords that follow the type specified. If
904 multiple parameter attributes are needed, they are space separated. For
905 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000906
907<div class="doc_code">
908<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000909declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000910declare i32 @atoi(i8 zeroext)
911declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000912</pre>
913</div>
914
Bill Wendlingf85859d2009-07-20 02:29:24 +0000915<p>Note that any attributes for the function result (<tt>nounwind</tt>,
916 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000917
Bill Wendlingf85859d2009-07-20 02:29:24 +0000918<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000919
Bill Wendlingf85859d2009-07-20 02:29:24 +0000920<dl>
921 <dt><tt>zeroext</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000922 <dd>This indicates to the code generator that the parameter or return value
923 should be zero-extended to a 32-bit value by the caller (for a parameter)
924 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000925
Bill Wendlingf85859d2009-07-20 02:29:24 +0000926 <dt><tt>signext</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000927 <dd>This indicates to the code generator that the parameter or return value
928 should be sign-extended to a 32-bit value by the caller (for a parameter)
929 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000930
Bill Wendlingf85859d2009-07-20 02:29:24 +0000931 <dt><tt>inreg</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000932 <dd>This indicates that this parameter or return value should be treated in a
933 special target-dependent fashion during while emitting code for a function
934 call or return (usually, by putting it in a register as opposed to memory,
935 though some targets use it to distinguish between two different kinds of
936 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000937
Bill Wendlingf85859d2009-07-20 02:29:24 +0000938 <dt><tt><a name="byval">byval</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000939 <dd>This indicates that the pointer parameter should really be passed by value
940 to the function. The attribute implies that a hidden copy of the pointee
941 is made between the caller and the callee, so the callee is unable to
942 modify the value in the callee. This attribute is only valid on LLVM
943 pointer arguments. It is generally used to pass structs and arrays by
944 value, but is also valid on pointers to scalars. The copy is considered
945 to belong to the caller not the callee (for example,
946 <tt><a href="#readonly">readonly</a></tt> functions should not write to
947 <tt>byval</tt> parameters). This is not a valid attribute for return
948 values. The byval attribute also supports specifying an alignment with
949 the align attribute. This has a target-specific effect on the code
950 generator that usually indicates a desired alignment for the synthesized
951 stack slot.</dd>
952
953 <dt><tt>sret</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000954 <dd>This indicates that the pointer parameter specifies the address of a
955 structure that is the return value of the function in the source program.
956 This pointer must be guaranteed by the caller to be valid: loads and
957 stores to the structure may be assumed by the callee to not to trap. This
958 may only be applied to the first parameter. This is not a valid attribute
959 for return values. </dd>
960
961 <dt><tt>noalias</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000962 <dd>This indicates that the pointer does not alias any global or any other
963 parameter. The caller is responsible for ensuring that this is the
964 case. On a function return value, <tt>noalias</tt> additionally indicates
965 that the pointer does not alias any other pointers visible to the
966 caller. For further details, please see the discussion of the NoAlias
967 response in
968 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
969 analysis</a>.</dd>
970
971 <dt><tt>nocapture</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000972 <dd>This indicates that the callee does not make any copies of the pointer
973 that outlive the callee itself. This is not a valid attribute for return
974 values.</dd>
975
976 <dt><tt>nest</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000977 <dd>This indicates that the pointer parameter can be excised using the
978 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
979 attribute for return values.</dd>
980</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000981
982</div>
983
984<!-- ======================================================================= -->
985<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000986 <a name="gc">Garbage Collector Names</a>
987</div>
988
989<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000990
Bill Wendlingf85859d2009-07-20 02:29:24 +0000991<p>Each function may specify a garbage collector name, which is simply a
992 string:</p>
993
994<div class="doc_code">
995<pre>
996define void @f() gc "name" { ...
997</pre>
998</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000999
1000<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +00001001 collector which will cause the compiler to alter its output in order to
1002 support the named garbage collection algorithm.</p>
1003
Gordon Henriksen13fe5e32007-12-10 03:18:06 +00001004</div>
1005
1006<!-- ======================================================================= -->
1007<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +00001008 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +00001009</div>
1010
1011<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +00001012
Bill Wendlingf85859d2009-07-20 02:29:24 +00001013<p>Function attributes are set to communicate additional information about a
1014 function. Function attributes are considered to be part of the function, not
1015 of the function type, so functions with different parameter attributes can
1016 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +00001017
Bill Wendlingf85859d2009-07-20 02:29:24 +00001018<p>Function attributes are simple keywords that follow the type specified. If
1019 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +00001020
1021<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +00001022<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +00001023define void @f() noinline { ... }
1024define void @f() alwaysinline { ... }
1025define void @f() alwaysinline optsize { ... }
1026define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +00001027</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +00001028</div>
1029
Bill Wendling74d3eac2008-09-07 10:26:33 +00001030<dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001031 <dt><tt>alwaysinline</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001032 <dd>This attribute indicates that the inliner should attempt to inline this
1033 function into callers whenever possible, ignoring any active inlining size
1034 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +00001035
Bill Wendlingf85859d2009-07-20 02:29:24 +00001036 <dt><tt>noinline</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001037 <dd>This attribute indicates that the inliner should never inline this
1038 function in any situation. This attribute may not be used together with
1039 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +00001040
Bill Wendlingf85859d2009-07-20 02:29:24 +00001041 <dt><tt>optsize</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001042 <dd>This attribute suggests that optimization passes and code generator passes
1043 make choices that keep the code size of this function low, and otherwise
1044 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +00001045
Bill Wendlingf85859d2009-07-20 02:29:24 +00001046 <dt><tt>noreturn</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001047 <dd>This function attribute indicates that the function never returns
1048 normally. This produces undefined behavior at runtime if the function
1049 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +00001050
Bill Wendlingf85859d2009-07-20 02:29:24 +00001051 <dt><tt>nounwind</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001052 <dd>This function attribute indicates that the function never returns with an
1053 unwind or exceptional control flow. If the function does unwind, its
1054 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +00001055
Bill Wendlingf85859d2009-07-20 02:29:24 +00001056 <dt><tt>readnone</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001057 <dd>This attribute indicates that the function computes its result (or decides
1058 to unwind an exception) based strictly on its arguments, without
1059 dereferencing any pointer arguments or otherwise accessing any mutable
1060 state (e.g. memory, control registers, etc) visible to caller functions.
1061 It does not write through any pointer arguments
1062 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1063 changes any state visible to callers. This means that it cannot unwind
1064 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1065 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +00001066
Bill Wendlingf85859d2009-07-20 02:29:24 +00001067 <dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001068 <dd>This attribute indicates that the function does not write through any
1069 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1070 arguments) or otherwise modify any state (e.g. memory, control registers,
1071 etc) visible to caller functions. It may dereference pointer arguments
1072 and read state that may be set in the caller. A readonly function always
1073 returns the same value (or unwinds an exception identically) when called
1074 with the same set of arguments and global state. It cannot unwind an
1075 exception by calling the <tt>C++</tt> exception throwing methods, but may
1076 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +00001077
Bill Wendlingf85859d2009-07-20 02:29:24 +00001078 <dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001079 <dd>This attribute indicates that the function should emit a stack smashing
1080 protector. It is in the form of a "canary"&mdash;a random value placed on
1081 the stack before the local variables that's checked upon return from the
1082 function to see if it has been overwritten. A heuristic is used to
1083 determine if a function needs stack protectors or not.<br>
1084<br>
1085 If a function that has an <tt>ssp</tt> attribute is inlined into a
1086 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1087 function will have an <tt>ssp</tt> attribute.</dd>
1088
1089 <dt><tt>sspreq</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001090 <dd>This attribute indicates that the function should <em>always</em> emit a
1091 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +00001092 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1093<br>
1094 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1095 function that doesn't have an <tt>sspreq</tt> attribute or which has
1096 an <tt>ssp</tt> attribute, then the resulting function will have
1097 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001098
1099 <dt><tt>noredzone</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001100 <dd>This attribute indicates that the code generator should not use a red
1101 zone, even if the target-specific ABI normally permits it.</dd>
1102
1103 <dt><tt>noimplicitfloat</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001104 <dd>This attributes disables implicit floating point instructions.</dd>
1105
1106 <dt><tt>naked</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001107 <dd>This attribute disables prologue / epilogue emission for the function.
1108 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +00001109</dl>
1110
Devang Pateld468f1c2008-09-04 23:05:13 +00001111</div>
1112
1113<!-- ======================================================================= -->
1114<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001115 <a name="moduleasm">Module-Level Inline Assembly</a>
1116</div>
1117
1118<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00001119
1120<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1121 the GCC "file scope inline asm" blocks. These blocks are internally
1122 concatenated by LLVM and treated as a single unit, but may be separated in
1123 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001124
1125<div class="doc_code">
1126<pre>
1127module asm "inline asm code goes here"
1128module asm "more can go here"
1129</pre>
1130</div>
1131
1132<p>The strings can contain any character by escaping non-printable characters.
1133 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlingf85859d2009-07-20 02:29:24 +00001134 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001135
Bill Wendlingf85859d2009-07-20 02:29:24 +00001136<p>The inline asm code is simply printed to the machine code .s file when
1137 assembly code is generated.</p>
1138
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001139</div>
1140
1141<!-- ======================================================================= -->
1142<div class="doc_subsection">
1143 <a name="datalayout">Data Layout</a>
1144</div>
1145
1146<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00001147
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001148<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +00001149 data is to be laid out in memory. The syntax for the data layout is
1150 simply:</p>
1151
1152<div class="doc_code">
1153<pre>
1154target datalayout = "<i>layout specification</i>"
1155</pre>
1156</div>
1157
1158<p>The <i>layout specification</i> consists of a list of specifications
1159 separated by the minus sign character ('-'). Each specification starts with
1160 a letter and may include other information after the letter to define some
1161 aspect of the data layout. The specifications accepted are as follows:</p>
1162
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001163<dl>
1164 <dt><tt>E</tt></dt>
1165 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlingf85859d2009-07-20 02:29:24 +00001166 bits with the most significance have the lowest address location.</dd>
1167
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001168 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +00001169 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +00001170 the bits with the least significance have the lowest address
1171 location.</dd>
1172
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001173 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1174 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlingf85859d2009-07-20 02:29:24 +00001175 <i>preferred</i> alignments. All sizes are in bits. Specifying
1176 the <i>pref</i> alignment is optional. If omitted, the
1177 preceding <tt>:</tt> should be omitted too.</dd>
1178
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001179 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1180 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +00001181 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1182
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001183 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1184 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +00001185 <i>size</i>.</dd>
1186
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001187 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1188 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +00001189 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1190 (double).</dd>
1191
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001192 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1193 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +00001194 <i>size</i>.</dd>
1195
Daniel Dunbard88a97b2009-06-08 22:17:53 +00001196 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1197 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +00001198 <i>size</i>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001199</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001200
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001201<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +00001202 default set of specifications which are then (possibly) overriden by the
1203 specifications in the <tt>datalayout</tt> keyword. The default specifications
1204 are given in this list:</p>
1205
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001206<ul>
1207 <li><tt>E</tt> - big endian</li>
1208 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1209 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1210 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1211 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1212 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +00001213 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001214 alignment of 64-bits</li>
1215 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1216 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1217 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1218 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1219 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +00001220 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001221</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001222
1223<p>When LLVM is determining the alignment for a given type, it uses the
1224 following rules:</p>
1225
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001226<ol>
1227 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlingf85859d2009-07-20 02:29:24 +00001228 specification is used.</li>
1229
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001230 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlingf85859d2009-07-20 02:29:24 +00001231 smallest integer type that is larger than the bitwidth of the sought type
1232 is used. If none of the specifications are larger than the bitwidth then
1233 the the largest integer type is used. For example, given the default
1234 specifications above, the i7 type will use the alignment of i8 (next
1235 largest) while both i65 and i256 will use the alignment of i64 (largest
1236 specified).</li>
1237
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001238 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlingf85859d2009-07-20 02:29:24 +00001239 largest vector type that is smaller than the sought vector type will be
1240 used as a fall back. This happens because &lt;128 x double&gt; can be
1241 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001242</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001243
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001244</div>
1245
1246<!-- *********************************************************************** -->
1247<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1248<!-- *********************************************************************** -->
1249
1250<div class="doc_text">
1251
1252<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +00001253 intermediate representation. Being typed enables a number of optimizations
1254 to be performed on the intermediate representation directly, without having
1255 to do extra analyses on the side before the transformation. A strong type
1256 system makes it easier to read the generated code and enables novel analyses
1257 and transformations that are not feasible to perform on normal three address
1258 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001259
1260</div>
1261
1262<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +00001263<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001264Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001265
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001266<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00001267
1268<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001269
1270<table border="1" cellspacing="0" cellpadding="4">
1271 <tbody>
1272 <tr><th>Classification</th><th>Types</th></tr>
1273 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +00001274 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001275 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1276 </tr>
1277 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +00001278 <td><a href="#t_floating">floating point</a></td>
1279 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001280 </tr>
1281 <tr>
1282 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +00001283 <td><a href="#t_integer">integer</a>,
1284 <a href="#t_floating">floating point</a>,
1285 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +00001286 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +00001287 <a href="#t_struct">structure</a>,
1288 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +00001289 <a href="#t_label">label</a>,
1290 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001291 </td>
1292 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +00001293 <tr>
1294 <td><a href="#t_primitive">primitive</a></td>
1295 <td><a href="#t_label">label</a>,
1296 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +00001297 <a href="#t_floating">floating point</a>,
1298 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +00001299 </tr>
1300 <tr>
1301 <td><a href="#t_derived">derived</a></td>
1302 <td><a href="#t_integer">integer</a>,
1303 <a href="#t_array">array</a>,
1304 <a href="#t_function">function</a>,
1305 <a href="#t_pointer">pointer</a>,
1306 <a href="#t_struct">structure</a>,
1307 <a href="#t_pstruct">packed structure</a>,
1308 <a href="#t_vector">vector</a>,
1309 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +00001310 </td>
Chris Lattner488772f2008-01-04 04:32:38 +00001311 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001312 </tbody>
1313</table>
1314
Bill Wendlingf85859d2009-07-20 02:29:24 +00001315<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1316 important. Values of these types are the only ones which can be produced by
1317 instructions, passed as arguments, or used as operands to instructions.</p>
1318
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001319</div>
1320
1321<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +00001322<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +00001323
Chris Lattner488772f2008-01-04 04:32:38 +00001324<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00001325
Chris Lattner488772f2008-01-04 04:32:38 +00001326<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +00001327 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +00001328
Chris Lattner86437612008-01-04 04:34:14 +00001329</div>
1330
Chris Lattner488772f2008-01-04 04:32:38 +00001331<!-- _______________________________________________________________________ -->
1332<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1333
1334<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00001335
1336<table>
1337 <tbody>
1338 <tr><th>Type</th><th>Description</th></tr>
1339 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1340 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1341 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1342 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1343 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1344 </tbody>
1345</table>
1346
Chris Lattner488772f2008-01-04 04:32:38 +00001347</div>
1348
1349<!-- _______________________________________________________________________ -->
1350<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1351
1352<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +00001353
Chris Lattner488772f2008-01-04 04:32:38 +00001354<h5>Overview:</h5>
1355<p>The void type does not represent any value and has no size.</p>
1356
1357<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +00001358<pre>
1359 void
1360</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +00001361
Chris Lattner488772f2008-01-04 04:32:38 +00001362</div>
1363
1364<!-- _______________________________________________________________________ -->
1365<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1366
1367<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +00001368
Chris Lattner488772f2008-01-04 04:32:38 +00001369<h5>Overview:</h5>
1370<p>The label type represents code labels.</p>
1371
1372<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +00001373<pre>
1374 label
1375</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +00001376
Chris Lattner488772f2008-01-04 04:32:38 +00001377</div>
1378
Nick Lewycky29aaef82009-05-30 05:06:04 +00001379<!-- _______________________________________________________________________ -->
1380<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1381
1382<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +00001383
Nick Lewycky29aaef82009-05-30 05:06:04 +00001384<h5>Overview:</h5>
1385<p>The metadata type represents embedded metadata. The only derived type that
Bill Wendlingf85859d2009-07-20 02:29:24 +00001386 may contain metadata is <tt>metadata*</tt> or a function type that returns or
1387 takes metadata typed parameters, but not pointer to metadata types.</p>
Nick Lewycky29aaef82009-05-30 05:06:04 +00001388
1389<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +00001390<pre>
1391 metadata
1392</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +00001393
Nick Lewycky29aaef82009-05-30 05:06:04 +00001394</div>
1395
Chris Lattner488772f2008-01-04 04:32:38 +00001396
1397<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001398<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1399
1400<div class="doc_text">
1401
Bill Wendlingf85859d2009-07-20 02:29:24 +00001402<p>The real power in LLVM comes from the derived types in the system. This is
1403 what allows a programmer to represent arrays, functions, pointers, and other
1404 useful types. Note that these derived types may be recursive: For example,
1405 it is possible to have a two dimensional array.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001406
1407</div>
1408
1409<!-- _______________________________________________________________________ -->
1410<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1411
1412<div class="doc_text">
1413
1414<h5>Overview:</h5>
1415<p>The integer type is a very simple derived type that simply specifies an
Bill Wendlingf85859d2009-07-20 02:29:24 +00001416 arbitrary bit width for the integer type desired. Any bit width from 1 bit to
1417 2^23-1 (about 8 million) can be specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001418
1419<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001420<pre>
1421 iN
1422</pre>
1423
1424<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001425 value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001426
1427<h5>Examples:</h5>
1428<table class="layout">
Nick Lewycky39382d62009-05-24 02:46:06 +00001429 <tr class="layout">
1430 <td class="left"><tt>i1</tt></td>
1431 <td class="left">a single-bit integer.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001432 </tr>
Nick Lewycky39382d62009-05-24 02:46:06 +00001433 <tr class="layout">
1434 <td class="left"><tt>i32</tt></td>
1435 <td class="left">a 32-bit integer.</td>
1436 </tr>
1437 <tr class="layout">
1438 <td class="left"><tt>i1942652</tt></td>
1439 <td class="left">a really big integer of over 1 million bits.</td>
1440 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001441</table>
djge93155c2009-01-24 15:58:40 +00001442
Bill Wendlingf85859d2009-07-20 02:29:24 +00001443<p>Note that the code generator does not yet support large integer types to be
1444 used as function return types. The specific limit on how large a return type
1445 the code generator can currently handle is target-dependent; currently it's
1446 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
djge93155c2009-01-24 15:58:40 +00001447
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001448</div>
1449
1450<!-- _______________________________________________________________________ -->
1451<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1452
1453<div class="doc_text">
1454
1455<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001456<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +00001457 sequentially in memory. The array type requires a size (number of elements)
1458 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001459
1460<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001461<pre>
1462 [&lt;# elements&gt; x &lt;elementtype&gt;]
1463</pre>
1464
Bill Wendlingf85859d2009-07-20 02:29:24 +00001465<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1466 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001467
1468<h5>Examples:</h5>
1469<table class="layout">
1470 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +00001471 <td class="left"><tt>[40 x i32]</tt></td>
1472 <td class="left">Array of 40 32-bit integer values.</td>
1473 </tr>
1474 <tr class="layout">
1475 <td class="left"><tt>[41 x i32]</tt></td>
1476 <td class="left">Array of 41 32-bit integer values.</td>
1477 </tr>
1478 <tr class="layout">
1479 <td class="left"><tt>[4 x i8]</tt></td>
1480 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001481 </tr>
1482</table>
1483<p>Here are some examples of multidimensional arrays:</p>
1484<table class="layout">
1485 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +00001486 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1487 <td class="left">3x4 array of 32-bit integer values.</td>
1488 </tr>
1489 <tr class="layout">
1490 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1491 <td class="left">12x10 array of single precision floating point values.</td>
1492 </tr>
1493 <tr class="layout">
1494 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1495 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001496 </tr>
1497</table>
1498
Bill Wendlingf85859d2009-07-20 02:29:24 +00001499<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1500 length array. Normally, accesses past the end of an array are undefined in
1501 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1502 a special case, however, zero length arrays are recognized to be variable
1503 length. This allows implementation of 'pascal style arrays' with the LLVM
1504 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001505
Bill Wendlingf85859d2009-07-20 02:29:24 +00001506<p>Note that the code generator does not yet support large aggregate types to be
1507 used as function return types. The specific limit on how large an aggregate
1508 return type the code generator can currently handle is target-dependent, and
1509 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +00001510
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001511</div>
1512
1513<!-- _______________________________________________________________________ -->
1514<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001515
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001516<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +00001517
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001518<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001519<p>The function type can be thought of as a function signature. It consists of
1520 a return type and a list of formal parameter types. The return type of a
1521 function type is a scalar type, a void type, or a struct type. If the return
1522 type is a struct type then all struct elements must be of first class types,
1523 and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +00001524
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001525<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +00001526<pre>
1527 &lt;returntype list&gt; (&lt;parameter list&gt;)
1528</pre>
1529
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001530<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlingf85859d2009-07-20 02:29:24 +00001531 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1532 which indicates that the function takes a variable number of arguments.
1533 Variable argument functions can access their arguments with
1534 the <a href="#int_varargs">variable argument handling intrinsic</a>
1535 functions. '<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1536 <a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +00001537
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001538<h5>Examples:</h5>
1539<table class="layout">
1540 <tr class="layout">
1541 <td class="left"><tt>i32 (i32)</tt></td>
1542 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1543 </td>
1544 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +00001545 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001546 </tt></td>
1547 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1548 an <tt>i16</tt> that should be sign extended and a
1549 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1550 <tt>float</tt>.
1551 </td>
1552 </tr><tr class="layout">
1553 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1554 <td class="left">A vararg function that takes at least one
1555 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1556 which returns an integer. This is the signature for <tt>printf</tt> in
1557 LLVM.
1558 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +00001559 </tr><tr class="layout">
1560 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +00001561 <td class="left">A function taking an <tt>i32</tt>, returning two
1562 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +00001563 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001564 </tr>
1565</table>
1566
1567</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001568
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001569<!-- _______________________________________________________________________ -->
1570<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001571
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001572<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00001573
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001574<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001575<p>The structure type is used to represent a collection of data members together
1576 in memory. The packing of the field types is defined to match the ABI of the
1577 underlying processor. The elements of a structure may be any type that has a
1578 size.</p>
1579
1580<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1581 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1582 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1583
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001584<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +00001585<pre>
1586 { &lt;type list&gt; }
1587</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001588
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001589<h5>Examples:</h5>
1590<table class="layout">
1591 <tr class="layout">
1592 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1593 <td class="left">A triple of three <tt>i32</tt> values</td>
1594 </tr><tr class="layout">
1595 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1596 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1597 second element is a <a href="#t_pointer">pointer</a> to a
1598 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1599 an <tt>i32</tt>.</td>
1600 </tr>
1601</table>
djge93155c2009-01-24 15:58:40 +00001602
Bill Wendlingf85859d2009-07-20 02:29:24 +00001603<p>Note that the code generator does not yet support large aggregate types to be
1604 used as function return types. The specific limit on how large an aggregate
1605 return type the code generator can currently handle is target-dependent, and
1606 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +00001607
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001608</div>
1609
1610<!-- _______________________________________________________________________ -->
1611<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1612</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001613
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001614<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00001615
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001616<h5>Overview:</h5>
1617<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +00001618 together in memory. There is no padding between fields. Further, the
1619 alignment of a packed structure is 1 byte. The elements of a packed
1620 structure may be any type that has a size.</p>
1621
1622<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1623 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1624 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1625
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001626<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +00001627<pre>
1628 &lt; { &lt;type list&gt; } &gt;
1629</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001630
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001631<h5>Examples:</h5>
1632<table class="layout">
1633 <tr class="layout">
1634 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1635 <td class="left">A triple of three <tt>i32</tt> values</td>
1636 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +00001637 <td class="left">
1638<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001639 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1640 second element is a <a href="#t_pointer">pointer</a> to a
1641 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1642 an <tt>i32</tt>.</td>
1643 </tr>
1644</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001645
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001646</div>
1647
1648<!-- _______________________________________________________________________ -->
1649<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +00001650
Bill Wendlingf85859d2009-07-20 02:29:24 +00001651<div class="doc_text">
1652
1653<h5>Overview:</h5>
1654<p>As in many languages, the pointer type represents a pointer or reference to
1655 another object, which must live in memory. Pointer types may have an optional
1656 address space attribute defining the target-specific numbered address space
1657 where the pointed-to object resides. The default address space is zero.</p>
1658
1659<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1660 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +00001661
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001662<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +00001663<pre>
1664 &lt;type&gt; *
1665</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001666
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001667<h5>Examples:</h5>
1668<table class="layout">
1669 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +00001670 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +00001671 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1672 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1673 </tr>
1674 <tr class="layout">
1675 <td class="left"><tt>i32 (i32 *) *</tt></td>
1676 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001677 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +00001678 <tt>i32</tt>.</td>
1679 </tr>
1680 <tr class="layout">
1681 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1682 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1683 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001684 </tr>
1685</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001686
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001687</div>
1688
1689<!-- _______________________________________________________________________ -->
1690<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001691
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001692<div class="doc_text">
1693
1694<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001695<p>A vector type is a simple derived type that represents a vector of elements.
1696 Vector types are used when multiple primitive data are operated in parallel
1697 using a single instruction (SIMD). A vector type requires a size (number of
1698 elements) and an underlying primitive data type. Vectors must have a power
1699 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1700 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001701
1702<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001703<pre>
1704 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1705</pre>
1706
Bill Wendlingf85859d2009-07-20 02:29:24 +00001707<p>The number of elements is a constant integer value; elementtype may be any
1708 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001709
1710<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001711<table class="layout">
1712 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +00001713 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1714 <td class="left">Vector of 4 32-bit integer values.</td>
1715 </tr>
1716 <tr class="layout">
1717 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1718 <td class="left">Vector of 8 32-bit floating-point values.</td>
1719 </tr>
1720 <tr class="layout">
1721 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1722 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001723 </tr>
1724</table>
djge93155c2009-01-24 15:58:40 +00001725
Bill Wendlingf85859d2009-07-20 02:29:24 +00001726<p>Note that the code generator does not yet support large vector types to be
1727 used as function return types. The specific limit on how large a vector
1728 return type codegen can currently handle is target-dependent; currently it's
1729 often a few times longer than a hardware vector register.</p>
djge93155c2009-01-24 15:58:40 +00001730
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001731</div>
1732
1733<!-- _______________________________________________________________________ -->
1734<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1735<div class="doc_text">
1736
1737<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001738<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +00001739 corresponds (for example) to the C notion of a forward declared structure
1740 type. In LLVM, opaque types can eventually be resolved to any type (not just
1741 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001742
1743<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001744<pre>
1745 opaque
1746</pre>
1747
1748<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001749<table class="layout">
1750 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +00001751 <td class="left"><tt>opaque</tt></td>
1752 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001753 </tr>
1754</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001755
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001756</div>
1757
Chris Lattner515195a2009-02-02 07:32:36 +00001758<!-- ======================================================================= -->
1759<div class="doc_subsection">
1760 <a name="t_uprefs">Type Up-references</a>
1761</div>
1762
1763<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00001764
Chris Lattner515195a2009-02-02 07:32:36 +00001765<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001766<p>An "up reference" allows you to refer to a lexically enclosing type without
1767 requiring it to have a name. For instance, a structure declaration may
1768 contain a pointer to any of the types it is lexically a member of. Example
1769 of up references (with their equivalent as named type declarations)
1770 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +00001771
1772<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +00001773 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +00001774 { \2 }* %y = type { %y }*
1775 \1* %z = type %z*
1776</pre>
1777
Bill Wendlingf85859d2009-07-20 02:29:24 +00001778<p>An up reference is needed by the asmprinter for printing out cyclic types
1779 when there is no declared name for a type in the cycle. Because the
1780 asmprinter does not want to print out an infinite type string, it needs a
1781 syntax to handle recursive types that have no names (all names are optional
1782 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +00001783
1784<h5>Syntax:</h5>
1785<pre>
1786 \&lt;level&gt;
1787</pre>
1788
Bill Wendlingf85859d2009-07-20 02:29:24 +00001789<p>The level is the count of the lexical type that is being referred to.</p>
Chris Lattner515195a2009-02-02 07:32:36 +00001790
1791<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +00001792<table class="layout">
1793 <tr class="layout">
1794 <td class="left"><tt>\1*</tt></td>
1795 <td class="left">Self-referential pointer.</td>
1796 </tr>
1797 <tr class="layout">
1798 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1799 <td class="left">Recursive structure where the upref refers to the out-most
1800 structure.</td>
1801 </tr>
1802</table>
Chris Lattner515195a2009-02-02 07:32:36 +00001803
Bill Wendlingf85859d2009-07-20 02:29:24 +00001804</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001805
1806<!-- *********************************************************************** -->
1807<div class="doc_section"> <a name="constants">Constants</a> </div>
1808<!-- *********************************************************************** -->
1809
1810<div class="doc_text">
1811
1812<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +00001813 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001814
1815</div>
1816
1817<!-- ======================================================================= -->
1818<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1819
1820<div class="doc_text">
1821
1822<dl>
1823 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001824 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Bill Wendlingf85859d2009-07-20 02:29:24 +00001825 constants of the <tt><a href="#t_primitive">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001826
1827 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001828 <dd>Standard integers (such as '4') are constants of
1829 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1830 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001831
1832 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001833 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +00001834 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1835 notation (see below). The assembler requires the exact decimal value of a
1836 floating-point constant. For example, the assembler accepts 1.25 but
1837 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1838 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001839
1840 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001841 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +00001842 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001843</dl>
1844
Bill Wendlingf85859d2009-07-20 02:29:24 +00001845<p>The one non-intuitive notation for constants is the hexadecimal form of
1846 floating point constants. For example, the form '<tt>double
1847 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1848 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1849 constants are required (and the only time that they are generated by the
1850 disassembler) is when a floating point constant must be emitted but it cannot
1851 be represented as a decimal floating point number in a reasonable number of
1852 digits. For example, NaN's, infinities, and other special values are
1853 represented in their IEEE hexadecimal format so that assembly and disassembly
1854 do not cause any bits to change in the constants.</p>
1855
Dale Johannesenf82a52f2009-02-11 22:14:51 +00001856<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +00001857 represented using the 16-digit form shown above (which matches the IEEE754
1858 representation for double); float values must, however, be exactly
1859 representable as IEE754 single precision. Hexadecimal format is always used
1860 for long double, and there are three forms of long double. The 80-bit format
1861 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1862 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1863 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1864 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1865 currently supported target uses this format. Long doubles will only work if
1866 they match the long double format on your target. All hexadecimal formats
1867 are big-endian (sign bit at the left).</p>
1868
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001869</div>
1870
1871<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +00001872<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +00001873<a name="aggregateconstants"></a> <!-- old anchor -->
1874<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001875</div>
1876
1877<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00001878
Chris Lattner97063852009-02-28 18:32:25 +00001879<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +00001880 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001881
1882<dl>
1883 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001884 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +00001885 type definitions (a comma separated list of elements, surrounded by braces
1886 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1887 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1888 Structure constants must have <a href="#t_struct">structure type</a>, and
1889 the number and types of elements must match those specified by the
1890 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001891
1892 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001893 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +00001894 definitions (a comma separated list of elements, surrounded by square
1895 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1896 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1897 the number and types of elements must match those specified by the
1898 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001899
1900 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001901 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +00001902 definitions (a comma separated list of elements, surrounded by
1903 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1904 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1905 have <a href="#t_vector">vector type</a>, and the number and types of
1906 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001907
1908 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001909 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlingf85859d2009-07-20 02:29:24 +00001910 value to zero of <em>any</em> type, including scalar and aggregate types.
1911 This is often used to avoid having to print large zero initializers
1912 (e.g. for large arrays) and is always exactly equivalent to using explicit
1913 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +00001914
1915 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +00001916 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +00001917 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1918 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1919 be interpreted as part of the instruction stream, metadata is a place to
1920 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001921</dl>
1922
1923</div>
1924
1925<!-- ======================================================================= -->
1926<div class="doc_subsection">
1927 <a name="globalconstants">Global Variable and Function Addresses</a>
1928</div>
1929
1930<div class="doc_text">
1931
Bill Wendlingf85859d2009-07-20 02:29:24 +00001932<p>The addresses of <a href="#globalvars">global variables</a>
1933 and <a href="#functionstructure">functions</a> are always implicitly valid
1934 (link-time) constants. These constants are explicitly referenced when
1935 the <a href="#identifiers">identifier for the global</a> is used and always
1936 have <a href="#t_pointer">pointer</a> type. For example, the following is a
1937 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001938
1939<div class="doc_code">
1940<pre>
1941@X = global i32 17
1942@Y = global i32 42
1943@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1944</pre>
1945</div>
1946
1947</div>
1948
1949<!-- ======================================================================= -->
1950<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1951<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001952
Bill Wendlingf85859d2009-07-20 02:29:24 +00001953<p>The string '<tt>undef</tt>' is recognized as a type-less constant that has no
1954 specific value. Undefined values may be of any type and be used anywhere a
1955 constant is permitted.</p>
1956
1957<p>Undefined values indicate to the compiler that the program is well defined no
1958 matter what value is used, giving the compiler more freedom to optimize.</p>
1959
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001960</div>
1961
1962<!-- ======================================================================= -->
1963<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1964</div>
1965
1966<div class="doc_text">
1967
1968<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +00001969 to be used as constants. Constant expressions may be of
1970 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
1971 operation that does not have side effects (e.g. load and call are not
1972 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001973
1974<dl>
1975 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001976 <dd>Truncate a constant to another type. The bit size of CST must be larger
1977 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001978
1979 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001980 <dd>Zero extend a constant to another type. The bit size of CST must be
1981 smaller or equal to the bit size of TYPE. Both types must be
1982 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001983
1984 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001985 <dd>Sign extend a constant to another type. The bit size of CST must be
1986 smaller or equal to the bit size of TYPE. Both types must be
1987 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001988
1989 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001990 <dd>Truncate a floating point constant to another floating point type. The
1991 size of CST must be larger than the size of TYPE. Both types must be
1992 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001993
1994 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00001995 <dd>Floating point extend a constant to another type. The size of CST must be
1996 smaller or equal to the size of TYPE. Both types must be floating
1997 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001998
Reid Spencere6adee82007-07-31 14:40:14 +00001999 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002000 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +00002001 constant. TYPE must be a scalar or vector integer type. CST must be of
2002 scalar or vector floating point type. Both CST and TYPE must be scalars,
2003 or vectors of the same number of elements. If the value won't fit in the
2004 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002005
2006 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2007 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +00002008 constant. TYPE must be a scalar or vector integer type. CST must be of
2009 scalar or vector floating point type. Both CST and TYPE must be scalars,
2010 or vectors of the same number of elements. If the value won't fit in the
2011 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002012
2013 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2014 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +00002015 constant. TYPE must be a scalar or vector floating point type. CST must be
2016 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2017 vectors of the same number of elements. If the value won't fit in the
2018 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002019
2020 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2021 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +00002022 constant. TYPE must be a scalar or vector floating point type. CST must be
2023 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2024 vectors of the same number of elements. If the value won't fit in the
2025 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002026
2027 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2028 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +00002029 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2030 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2031 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002032
2033 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002034 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2035 type. CST must be of integer type. The CST value is zero extended,
2036 truncated, or unchanged to make it fit in a pointer size. This one is
2037 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002038
2039 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +00002040 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2041 are the same as those for the <a href="#i_bitcast">bitcast
2042 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002043
2044 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002045 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +00002046 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2047 instruction, the index list may have zero or more indexes, which are
2048 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002049
2050 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002051 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002052
2053 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2054 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2055
2056 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2057 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2058
2059 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002060 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2061 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002062
2063 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002064 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2065 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002066
2067 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002068 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2069 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002070
2071 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002072 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2073 be any of the <a href="#binaryops">binary</a>
2074 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2075 on operands are the same as those for the corresponding instruction
2076 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002077</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002078
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002079</div>
2080
Nick Lewycky4dcf8102009-04-04 07:22:01 +00002081<!-- ======================================================================= -->
2082<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2083</div>
2084
2085<div class="doc_text">
2086
Bill Wendlingf85859d2009-07-20 02:29:24 +00002087<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2088 stream without affecting the behaviour of the program. There are two
2089 metadata primitives, strings and nodes. All metadata has the
2090 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2091 point ('<tt>!</tt>').</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +00002092
2093<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf85859d2009-07-20 02:29:24 +00002094 any character by escaping non-printable characters with "\xx" where "xx" is
2095 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +00002096
2097<p>Metadata nodes are represented with notation similar to structure constants
Bill Wendlingf85859d2009-07-20 02:29:24 +00002098 (a comma separated list of elements, surrounded by braces and preceeded by an
2099 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2100 10}</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +00002101
Bill Wendlingf85859d2009-07-20 02:29:24 +00002102<p>A metadata node will attempt to track changes to the values it holds. In the
2103 event that a value is deleted, it will be replaced with a typeless
2104 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +00002105
Nick Lewycky4dcf8102009-04-04 07:22:01 +00002106<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingf85859d2009-07-20 02:29:24 +00002107 the program that isn't available in the instructions, or that isn't easily
2108 computable. Similarly, the code generator may expect a certain metadata
2109 format to be used to express debugging information.</p>
2110
Nick Lewycky4dcf8102009-04-04 07:22:01 +00002111</div>
2112
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002113<!-- *********************************************************************** -->
2114<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2115<!-- *********************************************************************** -->
2116
2117<!-- ======================================================================= -->
2118<div class="doc_subsection">
2119<a name="inlineasm">Inline Assembler Expressions</a>
2120</div>
2121
2122<div class="doc_text">
2123
Bill Wendlingf85859d2009-07-20 02:29:24 +00002124<p>LLVM supports inline assembler expressions (as opposed
2125 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2126 a special value. This value represents the inline assembler as a string
2127 (containing the instructions to emit), a list of operand constraints (stored
2128 as a string), and a flag that indicates whether or not the inline asm
2129 expression has side effects. An example inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002130
2131<div class="doc_code">
2132<pre>
2133i32 (i32) asm "bswap $0", "=r,r"
2134</pre>
2135</div>
2136
Bill Wendlingf85859d2009-07-20 02:29:24 +00002137<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2138 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2139 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002140
2141<div class="doc_code">
2142<pre>
2143%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2144</pre>
2145</div>
2146
Bill Wendlingf85859d2009-07-20 02:29:24 +00002147<p>Inline asms with side effects not visible in the constraint list must be
2148 marked as having side effects. This is done through the use of the
2149 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002150
2151<div class="doc_code">
2152<pre>
2153call void asm sideeffect "eieio", ""()
2154</pre>
2155</div>
2156
2157<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002158 documented here. Constraints on what can be done (e.g. duplication, moving,
2159 etc need to be documented). This is probably best done by reference to
2160 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002161
2162</div>
2163
Chris Lattner75c24e02009-07-20 05:55:19 +00002164
2165<!-- *********************************************************************** -->
2166<div class="doc_section">
2167 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2168</div>
2169<!-- *********************************************************************** -->
2170
2171<p>LLVM has a number of "magic" global variables that contain data that affect
2172code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +00002173of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2174section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2175by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +00002176
2177<!-- ======================================================================= -->
2178<div class="doc_subsection">
2179<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2180</div>
2181
2182<div class="doc_text">
2183
2184<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2185href="#linkage_appending">appending linkage</a>. This array contains a list of
2186pointers to global variables and functions which may optionally have a pointer
2187cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2188
2189<pre>
2190 @X = global i8 4
2191 @Y = global i32 123
2192
2193 @llvm.used = appending global [2 x i8*] [
2194 i8* @X,
2195 i8* bitcast (i32* @Y to i8*)
2196 ], section "llvm.metadata"
2197</pre>
2198
2199<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2200compiler, assembler, and linker are required to treat the symbol as if there is
2201a reference to the global that it cannot see. For example, if a variable has
2202internal linkage and no references other than that from the <tt>@llvm.used</tt>
2203list, it cannot be deleted. This is commonly used to represent references from
2204inline asms and other things the compiler cannot "see", and corresponds to
2205"attribute((used))" in GNU C.</p>
2206
2207<p>On some targets, the code generator must emit a directive to the assembler or
2208object file to prevent the assembler and linker from molesting the symbol.</p>
2209
2210</div>
2211
2212<!-- ======================================================================= -->
2213<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +00002214<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2215</div>
2216
2217<div class="doc_text">
2218
2219<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2220<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2221touching the symbol. On targets that support it, this allows an intelligent
2222linker to optimize references to the symbol without being impeded as it would be
2223by <tt>@llvm.used</tt>.</p>
2224
2225<p>This is a rare construct that should only be used in rare circumstances, and
2226should not be exposed to source languages.</p>
2227
2228</div>
2229
2230<!-- ======================================================================= -->
2231<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +00002232<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2233</div>
2234
2235<div class="doc_text">
2236
2237<p>TODO: Describe this.</p>
2238
2239</div>
2240
2241<!-- ======================================================================= -->
2242<div class="doc_subsection">
2243<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2244</div>
2245
2246<div class="doc_text">
2247
2248<p>TODO: Describe this.</p>
2249
2250</div>
2251
2252
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002253<!-- *********************************************************************** -->
2254<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2255<!-- *********************************************************************** -->
2256
2257<div class="doc_text">
2258
Bill Wendlingf85859d2009-07-20 02:29:24 +00002259<p>The LLVM instruction set consists of several different classifications of
2260 instructions: <a href="#terminators">terminator
2261 instructions</a>, <a href="#binaryops">binary instructions</a>,
2262 <a href="#bitwiseops">bitwise binary instructions</a>,
2263 <a href="#memoryops">memory instructions</a>, and
2264 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002265
2266</div>
2267
2268<!-- ======================================================================= -->
2269<div class="doc_subsection"> <a name="terminators">Terminator
2270Instructions</a> </div>
2271
2272<div class="doc_text">
2273
Bill Wendlingf85859d2009-07-20 02:29:24 +00002274<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2275 in a program ends with a "Terminator" instruction, which indicates which
2276 block should be executed after the current block is finished. These
2277 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2278 control flow, not values (the one exception being the
2279 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2280
2281<p>There are six different terminator instructions: the
2282 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2283 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2284 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
2285 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2286 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2287 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002288
2289</div>
2290
2291<!-- _______________________________________________________________________ -->
2292<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2293Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002294
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002295<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00002296
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002297<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +00002298<pre>
2299 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002300 ret void <i>; Return from void function</i>
2301</pre>
Chris Lattner43030e72008-04-23 04:59:35 +00002302
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002303<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002304<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2305 a value) from a function back to the caller.</p>
2306
2307<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2308 value and then causes control flow, and one that just causes control flow to
2309 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +00002310
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002311<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002312<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2313 return value. The type of the return value must be a
2314 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +00002315
Bill Wendlingf85859d2009-07-20 02:29:24 +00002316<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2317 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2318 value or a return value with a type that does not match its type, or if it
2319 has a void return type and contains a '<tt>ret</tt>' instruction with a
2320 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +00002321
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002322<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002323<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2324 the calling function's context. If the caller is a
2325 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2326 instruction after the call. If the caller was an
2327 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2328 the beginning of the "normal" destination block. If the instruction returns
2329 a value, that value shall set the call or invoke instruction's return
2330 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +00002331
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002332<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +00002333<pre>
2334 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002335 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +00002336 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002337</pre>
Dan Gohman60967192009-01-12 23:12:39 +00002338
djge93155c2009-01-24 15:58:40 +00002339<p>Note that the code generator does not yet fully support large
2340 return values. The specific sizes that are currently supported are
2341 dependent on the target. For integers, on 32-bit targets the limit
2342 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2343 For aggregate types, the current limits are dependent on the element
2344 types; for example targets are often limited to 2 total integer
2345 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +00002346
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002347</div>
2348<!-- _______________________________________________________________________ -->
2349<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002350
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002351<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00002352
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002353<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002354<pre>
2355 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 +00002356</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002357
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002358<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002359<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2360 different basic block in the current function. There are two forms of this
2361 instruction, corresponding to a conditional branch and an unconditional
2362 branch.</p>
2363
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002364<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002365<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2366 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2367 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2368 target.</p>
2369
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002370<h5>Semantics:</h5>
2371<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +00002372 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2373 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2374 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2375
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002376<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +00002377<pre>
2378Test:
2379 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2380 br i1 %cond, label %IfEqual, label %IfUnequal
2381IfEqual:
2382 <a href="#i_ret">ret</a> i32 1
2383IfUnequal:
2384 <a href="#i_ret">ret</a> i32 0
2385</pre>
2386
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002387</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002388
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002389<!-- _______________________________________________________________________ -->
2390<div class="doc_subsubsection">
2391 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2392</div>
2393
2394<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002395
Bill Wendlingf85859d2009-07-20 02:29:24 +00002396<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002397<pre>
2398 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2399</pre>
2400
2401<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002402<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlingf85859d2009-07-20 02:29:24 +00002403 several different places. It is a generalization of the '<tt>br</tt>'
2404 instruction, allowing a branch to occur to one of many possible
2405 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002406
2407<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002408<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +00002409 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2410 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2411 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002412
2413<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002414<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +00002415 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2416 is searched for the given value. If the value is found, control flow is
2417 transfered to the corresponding destination; otherwise, control flow is
2418 transfered to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002419
2420<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002421<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +00002422 <tt>switch</tt> instruction, this instruction may be code generated in
2423 different ways. For example, it could be generated as a series of chained
2424 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002425
2426<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002427<pre>
2428 <i>; Emulate a conditional br instruction</i>
2429 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +00002430 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002431
2432 <i>; Emulate an unconditional br instruction</i>
2433 switch i32 0, label %dest [ ]
2434
2435 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +00002436 switch i32 %val, label %otherwise [ i32 0, label %onzero
2437 i32 1, label %onone
2438 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002439</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002440
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002441</div>
2442
2443<!-- _______________________________________________________________________ -->
2444<div class="doc_subsubsection">
2445 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2446</div>
2447
2448<div class="doc_text">
2449
2450<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002451<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +00002452 &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 +00002453 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2454</pre>
2455
2456<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002457<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +00002458 function, with the possibility of control flow transfer to either the
2459 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2460 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2461 control flow will return to the "normal" label. If the callee (or any
2462 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2463 instruction, control is interrupted and continued at the dynamically nearest
2464 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002465
2466<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002467<p>This instruction requires several arguments:</p>
2468
2469<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002470 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2471 convention</a> the call should use. If none is specified, the call
2472 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +00002473
2474 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +00002475 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2476 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +00002477
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002478 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlingf85859d2009-07-20 02:29:24 +00002479 function value being invoked. In most cases, this is a direct function
2480 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2481 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002482
2483 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +00002484 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002485
2486 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingf85859d2009-07-20 02:29:24 +00002487 signature argument types. If the function signature indicates the
2488 function accepts a variable number of arguments, the extra arguments can
2489 be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002490
2491 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +00002492 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002493
2494 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +00002495 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002496
Devang Pateld0bfcc72008-10-07 17:48:33 +00002497 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +00002498 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2499 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002500</ol>
2501
2502<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002503<p>This instruction is designed to operate as a standard
2504 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2505 primary difference is that it establishes an association with a label, which
2506 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002507
2508<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +00002509 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2510 exception. Additionally, this is important for implementation of
2511 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002512
Bill Wendlingf85859d2009-07-20 02:29:24 +00002513<p>For the purposes of the SSA form, the definition of the value returned by the
2514 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2515 block to the "normal" label. If the callee unwinds then no return value is
2516 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +00002517
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002518<h5>Example:</h5>
2519<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +00002520 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002521 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +00002522 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002523 unwind label %TestCleanup <i>; {i32}:retval set</i>
2524</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002525
Bill Wendlingf85859d2009-07-20 02:29:24 +00002526</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002527
2528<!-- _______________________________________________________________________ -->
2529
2530<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2531Instruction</a> </div>
2532
2533<div class="doc_text">
2534
2535<h5>Syntax:</h5>
2536<pre>
2537 unwind
2538</pre>
2539
2540<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002541<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +00002542 at the first callee in the dynamic call stack which used
2543 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2544 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002545
2546<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +00002547<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +00002548 immediately halt. The dynamic call stack is then searched for the
2549 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2550 Once found, execution continues at the "exceptional" destination block
2551 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2552 instruction in the dynamic call chain, undefined behavior results.</p>
2553
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002554</div>
2555
2556<!-- _______________________________________________________________________ -->
2557
2558<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2559Instruction</a> </div>
2560
2561<div class="doc_text">
2562
2563<h5>Syntax:</h5>
2564<pre>
2565 unreachable
2566</pre>
2567
2568<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002569<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +00002570 instruction is used to inform the optimizer that a particular portion of the
2571 code is not reachable. This can be used to indicate that the code after a
2572 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002573
2574<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002575<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002576
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002577</div>
2578
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002579<!-- ======================================================================= -->
2580<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002581
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002582<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00002583
2584<p>Binary operators are used to do most of the computation in a program. They
2585 require two operands of the same type, execute an operation on them, and
2586 produce a single value. The operands might represent multiple data, as is
2587 the case with the <a href="#t_vector">vector</a> data type. The result value
2588 has the same type as its operands.</p>
2589
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002590<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002591
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002592</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002593
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002594<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +00002595<div class="doc_subsubsection">
2596 <a name="i_add">'<tt>add</tt>' Instruction</a>
2597</div>
2598
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002599<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +00002600
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002601<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002602<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +00002603 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman46e96012009-07-22 22:44:56 +00002604 &lt;result&gt; = nuw add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2605 &lt;result&gt; = nsw add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2606 &lt;result&gt; = nuw nsw add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002607</pre>
Chris Lattner6704c212008-05-20 20:48:21 +00002608
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002609<h5>Overview:</h5>
2610<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002611
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002612<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002613<p>The two arguments to the '<tt>add</tt>' instruction must
2614 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2615 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002616
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002617<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002618<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002619
Bill Wendlingf85859d2009-07-20 02:29:24 +00002620<p>If the sum has unsigned overflow, the result returned is the mathematical
2621 result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002622
Bill Wendlingf85859d2009-07-20 02:29:24 +00002623<p>Because LLVM integers use a two's complement representation, this instruction
2624 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002625
Dan Gohman46e96012009-07-22 22:44:56 +00002626<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2627 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2628 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2629 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +00002630
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002631<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002632<pre>
2633 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002634</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002635
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002636</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002637
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002638<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +00002639<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +00002640 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2641</div>
2642
2643<div class="doc_text">
2644
2645<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002646<pre>
2647 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2648</pre>
2649
2650<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002651<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2652
2653<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002654<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002655 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2656 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002657
2658<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002659<p>The value produced is the floating point sum of the two operands.</p>
2660
2661<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002662<pre>
2663 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2664</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002665
Dan Gohman7ce405e2009-06-04 22:49:04 +00002666</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002667
Dan Gohman7ce405e2009-06-04 22:49:04 +00002668<!-- _______________________________________________________________________ -->
2669<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +00002670 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2671</div>
2672
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002673<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +00002674
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002675<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002676<pre>
Dan Gohman46e96012009-07-22 22:44:56 +00002677 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2678 &lt;result&gt; = nuw sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2679 &lt;result&gt; = nsw sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2680 &lt;result&gt; = nuw nsw sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002681</pre>
Chris Lattner6704c212008-05-20 20:48:21 +00002682
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002683<h5>Overview:</h5>
2684<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +00002685 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002686
2687<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +00002688 '<tt>neg</tt>' instruction present in most other intermediate
2689 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002690
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002691<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002692<p>The two arguments to the '<tt>sub</tt>' instruction must
2693 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2694 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002695
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002696<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002697<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002698
Dan Gohman7ce405e2009-06-04 22:49:04 +00002699<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +00002700 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2701 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002702
Bill Wendlingf85859d2009-07-20 02:29:24 +00002703<p>Because LLVM integers use a two's complement representation, this instruction
2704 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002705
Dan Gohman46e96012009-07-22 22:44:56 +00002706<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2707 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2708 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2709 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +00002710
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002711<h5>Example:</h5>
2712<pre>
2713 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2714 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2715</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002716
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002717</div>
Chris Lattner6704c212008-05-20 20:48:21 +00002718
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002719<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +00002720<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +00002721 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2722</div>
2723
2724<div class="doc_text">
2725
2726<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002727<pre>
2728 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2729</pre>
2730
2731<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002732<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +00002733 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002734
2735<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +00002736 '<tt>fneg</tt>' instruction present in most other intermediate
2737 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002738
2739<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +00002740<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002741 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2742 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002743
2744<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002745<p>The value produced is the floating point difference of the two operands.</p>
2746
2747<h5>Example:</h5>
2748<pre>
2749 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2750 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2751</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002752
Dan Gohman7ce405e2009-06-04 22:49:04 +00002753</div>
2754
2755<!-- _______________________________________________________________________ -->
2756<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +00002757 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2758</div>
2759
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002760<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +00002761
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002762<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002763<pre>
Dan Gohman46e96012009-07-22 22:44:56 +00002764 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2765 &lt;result&gt; = nuw mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2766 &lt;result&gt; = nsw mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2767 &lt;result&gt; = nuw nsw mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002768</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002769
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002770<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002771<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002772
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002773<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002774<p>The two arguments to the '<tt>mul</tt>' instruction must
2775 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2776 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002777
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002778<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002779<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002780
Bill Wendlingf85859d2009-07-20 02:29:24 +00002781<p>If the result of the multiplication has unsigned overflow, the result
2782 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
2783 width of the result.</p>
2784
2785<p>Because LLVM integers use a two's complement representation, and the result
2786 is the same width as the operands, this instruction returns the correct
2787 result for both signed and unsigned integers. If a full product
2788 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
2789 be sign-extended or zero-extended as appropriate to the width of the full
2790 product.</p>
2791
Dan Gohman46e96012009-07-22 22:44:56 +00002792<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2793 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2794 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
2795 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +00002796
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002797<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002798<pre>
2799 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002800</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002801
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002802</div>
Chris Lattner6704c212008-05-20 20:48:21 +00002803
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002804<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +00002805<div class="doc_subsubsection">
2806 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
2807</div>
2808
2809<div class="doc_text">
2810
2811<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002812<pre>
2813 &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 +00002814</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002815
Dan Gohman7ce405e2009-06-04 22:49:04 +00002816<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002817<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002818
2819<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002820<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002821 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2822 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002823
2824<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002825<p>The value produced is the floating point product of the two operands.</p>
2826
2827<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002828<pre>
2829 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002830</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002831
Dan Gohman7ce405e2009-06-04 22:49:04 +00002832</div>
2833
2834<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002835<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2836</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002837
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002838<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00002839
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002840<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002841<pre>
2842 &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 +00002843</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002844
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002845<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002846<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002847
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002848<h5>Arguments:</h5>
2849<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002850 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2851 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002852
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002853<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +00002854<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002855
Chris Lattner9aba1e22008-01-28 00:36:27 +00002856<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +00002857 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2858
Chris Lattner9aba1e22008-01-28 00:36:27 +00002859<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002860
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002861<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002862<pre>
2863 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002864</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002865
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002866</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002867
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002868<!-- _______________________________________________________________________ -->
2869<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2870</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002871
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002872<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00002873
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002874<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002875<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +00002876 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2877 &lt;result&gt; = exact sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002878</pre>
Chris Lattner6704c212008-05-20 20:48:21 +00002879
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002880<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002881<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002882
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002883<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002884<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002885 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2886 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002887
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002888<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002889<p>The value produced is the signed integer quotient of the two operands rounded
2890 towards zero.</p>
2891
Chris Lattner9aba1e22008-01-28 00:36:27 +00002892<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +00002893 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2894
Chris Lattner9aba1e22008-01-28 00:36:27 +00002895<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +00002896 undefined behavior; this is a rare case, but can occur, for example, by doing
2897 a 32-bit division of -2147483648 by -1.</p>
2898
Dan Gohman67fa48e2009-07-22 00:04:19 +00002899<p>If the <tt>exact</tt> keyword is present, the result value of the
2900 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
2901 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +00002902
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002903<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002904<pre>
2905 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002906</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002907
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002908</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002909
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002910<!-- _______________________________________________________________________ -->
2911<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2912Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002913
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002914<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00002915
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002916<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002917<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +00002918 &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 +00002919</pre>
Chris Lattner6704c212008-05-20 20:48:21 +00002920
Bill Wendlingf85859d2009-07-20 02:29:24 +00002921<h5>Overview:</h5>
2922<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002923
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002924<h5>Arguments:</h5>
2925<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002926 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2927 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002928
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002929<h5>Semantics:</h5>
2930<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002931
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002932<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002933<pre>
2934 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002935</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002936
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002937</div>
Chris Lattner6704c212008-05-20 20:48:21 +00002938
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002939<!-- _______________________________________________________________________ -->
2940<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2941</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002942
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002943<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00002944
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002945<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002946<pre>
2947 &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 +00002948</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002949
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002950<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002951<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
2952 division of its two arguments.</p>
2953
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002954<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002955<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002956 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2957 values. Both arguments must have identical types.</p>
2958
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002959<h5>Semantics:</h5>
2960<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +00002961 This instruction always performs an unsigned division to get the
2962 remainder.</p>
2963
Chris Lattner9aba1e22008-01-28 00:36:27 +00002964<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +00002965 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2966
Chris Lattner9aba1e22008-01-28 00:36:27 +00002967<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002968
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002969<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002970<pre>
2971 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002972</pre>
2973
2974</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002975
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002976<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +00002977<div class="doc_subsubsection">
2978 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2979</div>
2980
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002981<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +00002982
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002983<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002984<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +00002985 &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 +00002986</pre>
Chris Lattner6704c212008-05-20 20:48:21 +00002987
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002988<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002989<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
2990 division of its two operands. This instruction can also take
2991 <a href="#t_vector">vector</a> versions of the values in which case the
2992 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +00002993
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002994<h5>Arguments:</h5>
2995<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002996 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2997 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002998
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002999<h5>Semantics:</h5>
3000<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +00003001 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3002 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3003 a value. For more information about the difference,
3004 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3005 Math Forum</a>. For a table of how this is implemented in various languages,
3006 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3007 Wikipedia: modulo operation</a>.</p>
3008
Chris Lattner9aba1e22008-01-28 00:36:27 +00003009<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +00003010 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3011
Chris Lattner9aba1e22008-01-28 00:36:27 +00003012<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +00003013 Overflow also leads to undefined behavior; this is a rare case, but can
3014 occur, for example, by taking the remainder of a 32-bit division of
3015 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3016 lets srem be implemented using instructions that return both the result of
3017 the division and the remainder.)</p>
3018
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003019<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003020<pre>
3021 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003022</pre>
3023
3024</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003025
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003026<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +00003027<div class="doc_subsubsection">
3028 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3029
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003030<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +00003031
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003032<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003033<pre>
3034 &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 +00003035</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003036
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003037<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003038<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3039 its two operands.</p>
3040
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003041<h5>Arguments:</h5>
3042<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00003043 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3044 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00003045
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003046<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003047<p>This instruction returns the <i>remainder</i> of a division. The remainder
3048 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00003049
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003050<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00003051<pre>
3052 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003053</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003054
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003055</div>
3056
3057<!-- ======================================================================= -->
3058<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3059Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003060
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003061<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003062
3063<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3064 program. They are generally very efficient instructions and can commonly be
3065 strength reduced from other instructions. They require two operands of the
3066 same type, execute an operation on them, and produce a single value. The
3067 resulting value is the same type as its operands.</p>
3068
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003069</div>
3070
3071<!-- _______________________________________________________________________ -->
3072<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3073Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003074
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003075<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003076
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003077<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003078<pre>
3079 &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 +00003080</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +00003081
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003082<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003083<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3084 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +00003085
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003086<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003087<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3088 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3089 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +00003090
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003091<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003092<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3093 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3094 is (statically or dynamically) negative or equal to or larger than the number
3095 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3096 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3097 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +00003098
Bill Wendlingf85859d2009-07-20 02:29:24 +00003099<h5>Example:</h5>
3100<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003101 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3102 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3103 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +00003104 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +00003105 &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 +00003106</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003107
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003108</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003109
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003110<!-- _______________________________________________________________________ -->
3111<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3112Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003113
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003114<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003115
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003116<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003117<pre>
3118 &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 +00003119</pre>
3120
3121<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003122<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3123 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003124
3125<h5>Arguments:</h5>
3126<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +00003127 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3128 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003129
3130<h5>Semantics:</h5>
3131<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +00003132 significant bits of the result will be filled with zero bits after the shift.
3133 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3134 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3135 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3136 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003137
3138<h5>Example:</h5>
3139<pre>
3140 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3141 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3142 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3143 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +00003144 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +00003145 &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 +00003146</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003147
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003148</div>
3149
3150<!-- _______________________________________________________________________ -->
3151<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3152Instruction</a> </div>
3153<div class="doc_text">
3154
3155<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003156<pre>
3157 &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 +00003158</pre>
3159
3160<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003161<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3162 operand shifted to the right a specified number of bits with sign
3163 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003164
3165<h5>Arguments:</h5>
3166<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +00003167 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3168 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003169
3170<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003171<p>This instruction always performs an arithmetic shift right operation, The
3172 most significant bits of the result will be filled with the sign bit
3173 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3174 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3175 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3176 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003177
3178<h5>Example:</h5>
3179<pre>
3180 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3181 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3182 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3183 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +00003184 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +00003185 &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 +00003186</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003187
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003188</div>
3189
3190<!-- _______________________________________________________________________ -->
3191<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3192Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +00003193
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003194<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +00003195
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003196<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00003197<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +00003198 &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 +00003199</pre>
Chris Lattner6704c212008-05-20 20:48:21 +00003200
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003201<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003202<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3203 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00003204
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003205<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00003206<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00003207 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3208 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00003209
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003210<h5>Semantics:</h5>
3211<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003212
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003213<table border="1" cellspacing="0" cellpadding="4">
3214 <tbody>
3215 <tr>
3216 <td>In0</td>
3217 <td>In1</td>
3218 <td>Out</td>
3219 </tr>
3220 <tr>
3221 <td>0</td>
3222 <td>0</td>
3223 <td>0</td>
3224 </tr>
3225 <tr>
3226 <td>0</td>
3227 <td>1</td>
3228 <td>0</td>
3229 </tr>
3230 <tr>
3231 <td>1</td>
3232 <td>0</td>
3233 <td>0</td>
3234 </tr>
3235 <tr>
3236 <td>1</td>
3237 <td>1</td>
3238 <td>1</td>
3239 </tr>
3240 </tbody>
3241</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003242
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003243<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00003244<pre>
3245 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003246 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3247 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3248</pre>
3249</div>
3250<!-- _______________________________________________________________________ -->
3251<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +00003252
Bill Wendlingf85859d2009-07-20 02:29:24 +00003253<div class="doc_text">
3254
3255<h5>Syntax:</h5>
3256<pre>
3257 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3258</pre>
3259
3260<h5>Overview:</h5>
3261<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3262 two operands.</p>
3263
3264<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00003265<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00003266 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3267 values. Both arguments must have identical types.</p>
3268
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003269<h5>Semantics:</h5>
3270<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003271
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003272<table border="1" cellspacing="0" cellpadding="4">
3273 <tbody>
3274 <tr>
3275 <td>In0</td>
3276 <td>In1</td>
3277 <td>Out</td>
3278 </tr>
3279 <tr>
3280 <td>0</td>
3281 <td>0</td>
3282 <td>0</td>
3283 </tr>
3284 <tr>
3285 <td>0</td>
3286 <td>1</td>
3287 <td>1</td>
3288 </tr>
3289 <tr>
3290 <td>1</td>
3291 <td>0</td>
3292 <td>1</td>
3293 </tr>
3294 <tr>
3295 <td>1</td>
3296 <td>1</td>
3297 <td>1</td>
3298 </tr>
3299 </tbody>
3300</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003301
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003302<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003303<pre>
3304 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003305 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3306 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3307</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003308
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003309</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003310
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003311<!-- _______________________________________________________________________ -->
3312<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3313Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003314
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003315<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003316
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003317<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003318<pre>
3319 &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 +00003320</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003321
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003322<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003323<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3324 its two operands. The <tt>xor</tt> is used to implement the "one's
3325 complement" operation, which is the "~" operator in C.</p>
3326
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003327<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00003328<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00003329 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3330 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00003331
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003332<h5>Semantics:</h5>
3333<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003334
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003335<table border="1" cellspacing="0" cellpadding="4">
3336 <tbody>
3337 <tr>
3338 <td>In0</td>
3339 <td>In1</td>
3340 <td>Out</td>
3341 </tr>
3342 <tr>
3343 <td>0</td>
3344 <td>0</td>
3345 <td>0</td>
3346 </tr>
3347 <tr>
3348 <td>0</td>
3349 <td>1</td>
3350 <td>1</td>
3351 </tr>
3352 <tr>
3353 <td>1</td>
3354 <td>0</td>
3355 <td>1</td>
3356 </tr>
3357 <tr>
3358 <td>1</td>
3359 <td>1</td>
3360 <td>0</td>
3361 </tr>
3362 </tbody>
3363</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003364
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003365<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003366<pre>
3367 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003368 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3369 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3370 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3371</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003372
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003373</div>
3374
3375<!-- ======================================================================= -->
3376<div class="doc_subsection">
3377 <a name="vectorops">Vector Operations</a>
3378</div>
3379
3380<div class="doc_text">
3381
3382<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +00003383 target-independent manner. These instructions cover the element-access and
3384 vector-specific operations needed to process vectors effectively. While LLVM
3385 does directly support these vector operations, many sophisticated algorithms
3386 will want to use target-specific intrinsics to take full advantage of a
3387 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003388
3389</div>
3390
3391<!-- _______________________________________________________________________ -->
3392<div class="doc_subsubsection">
3393 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3394</div>
3395
3396<div class="doc_text">
3397
3398<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003399<pre>
3400 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3401</pre>
3402
3403<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003404<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3405 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003406
3407
3408<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003409<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3410 of <a href="#t_vector">vector</a> type. The second operand is an index
3411 indicating the position from which to extract the element. The index may be
3412 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003413
3414<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003415<p>The result is a scalar of the same type as the element type of
3416 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3417 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3418 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003419
3420<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003421<pre>
3422 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3423</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003424
Bill Wendlingf85859d2009-07-20 02:29:24 +00003425</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003426
3427<!-- _______________________________________________________________________ -->
3428<div class="doc_subsubsection">
3429 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3430</div>
3431
3432<div class="doc_text">
3433
3434<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003435<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +00003436 &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 +00003437</pre>
3438
3439<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003440<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3441 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003442
3443<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003444<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3445 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3446 whose type must equal the element type of the first operand. The third
3447 operand is an index indicating the position at which to insert the value.
3448 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003449
3450<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003451<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3452 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3453 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3454 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003455
3456<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003457<pre>
3458 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3459</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003460
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003461</div>
3462
3463<!-- _______________________________________________________________________ -->
3464<div class="doc_subsubsection">
3465 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3466</div>
3467
3468<div class="doc_text">
3469
3470<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003471<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +00003472 &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 +00003473</pre>
3474
3475<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003476<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3477 from two input vectors, returning a vector with the same element type as the
3478 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003479
3480<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003481<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3482 with types that match each other. The third argument is a shuffle mask whose
3483 element type is always 'i32'. The result of the instruction is a vector
3484 whose length is the same as the shuffle mask and whose element type is the
3485 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003486
Bill Wendlingf85859d2009-07-20 02:29:24 +00003487<p>The shuffle mask operand is required to be a constant vector with either
3488 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003489
3490<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003491<p>The elements of the two input vectors are numbered from left to right across
3492 both of the vectors. The shuffle mask operand specifies, for each element of
3493 the result vector, which element of the two input vectors the result element
3494 gets. The element selector may be undef (meaning "don't care") and the
3495 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003496
3497<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003498<pre>
3499 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3500 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3501 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3502 &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 +00003503 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3504 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3505 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3506 &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 +00003507</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003508
Bill Wendlingf85859d2009-07-20 02:29:24 +00003509</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003510
3511<!-- ======================================================================= -->
3512<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +00003513 <a name="aggregateops">Aggregate Operations</a>
3514</div>
3515
3516<div class="doc_text">
3517
Bill Wendlingf85859d2009-07-20 02:29:24 +00003518<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003519
3520</div>
3521
3522<!-- _______________________________________________________________________ -->
3523<div class="doc_subsubsection">
3524 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3525</div>
3526
3527<div class="doc_text">
3528
3529<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003530<pre>
3531 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3532</pre>
3533
3534<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003535<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3536 or array element from an aggregate value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003537
3538<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003539<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3540 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3541 operands are constant indices to specify which value to extract in a similar
3542 manner as indices in a
3543 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003544
3545<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003546<p>The result is the value at the position in the aggregate specified by the
3547 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003548
3549<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003550<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +00003551 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003552</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003553
Bill Wendlingf85859d2009-07-20 02:29:24 +00003554</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003555
3556<!-- _______________________________________________________________________ -->
3557<div class="doc_subsubsection">
3558 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3559</div>
3560
3561<div class="doc_text">
3562
3563<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003564<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +00003565 &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 +00003566</pre>
3567
3568<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003569<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3570 array element in an aggregate.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003571
3572
3573<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003574<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3575 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3576 second operand is a first-class value to insert. The following operands are
3577 constant indices indicating the position at which to insert the value in a
3578 similar manner as indices in a
3579 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3580 value to insert must have the same type as the value identified by the
3581 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003582
3583<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003584<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3585 that of <tt>val</tt> except that the value at the position specified by the
3586 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003587
3588<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003589<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +00003590 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003591</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003592
Dan Gohman74d6faf2008-05-12 23:51:09 +00003593</div>
3594
3595
3596<!-- ======================================================================= -->
3597<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003598 <a name="memoryops">Memory Access and Addressing Operations</a>
3599</div>
3600
3601<div class="doc_text">
3602
Bill Wendlingf85859d2009-07-20 02:29:24 +00003603<p>A key design point of an SSA-based representation is how it represents
3604 memory. In LLVM, no memory locations are in SSA form, which makes things
3605 very simple. This section describes how to read, write, allocate, and free
3606 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003607
3608</div>
3609
3610<!-- _______________________________________________________________________ -->
3611<div class="doc_subsubsection">
3612 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3613</div>
3614
3615<div class="doc_text">
3616
3617<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003618<pre>
3619 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3620</pre>
3621
3622<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003623<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3624 returns a pointer to it. The object is always allocated in the generic
3625 address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003626
3627<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003628<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlingf85859d2009-07-20 02:29:24 +00003629 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3630 system and returns a pointer of the appropriate type to the program. If
3631 "NumElements" is specified, it is the number of elements allocated, otherwise
3632 "NumElements" is defaulted to be one. If a constant alignment is specified,
3633 the value result of the allocation is guaranteed to be aligned to at least
3634 that boundary. If not specified, or if zero, the target can choose to align
3635 the allocation on any convenient boundary compatible with the type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003636
3637<p>'<tt>type</tt>' must be a sized type.</p>
3638
3639<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003640<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3641 pointer is returned. The result of a zero byte allocation is undefined. The
3642 result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003643
3644<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003645<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +00003646 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003647
3648 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3649 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3650 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3651 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3652 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3653</pre>
Dan Gohman60967192009-01-12 23:12:39 +00003654
Bill Wendlingf85859d2009-07-20 02:29:24 +00003655<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohman60967192009-01-12 23:12:39 +00003656
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003657</div>
3658
3659<!-- _______________________________________________________________________ -->
3660<div class="doc_subsubsection">
3661 <a name="i_free">'<tt>free</tt>' Instruction</a>
3662</div>
3663
3664<div class="doc_text">
3665
3666<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003667<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +00003668 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003669</pre>
3670
3671<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003672<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3673 to be reallocated in the future.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003674
3675<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003676<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3677 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003678
3679<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003680<p>Access to the memory pointed to by the pointer is no longer defined after
3681 this instruction executes. If the pointer is null, the operation is a
3682 noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003683
3684<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003685<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +00003686 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003687 free [4 x i8]* %array
3688</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003689
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003690</div>
3691
3692<!-- _______________________________________________________________________ -->
3693<div class="doc_subsubsection">
3694 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3695</div>
3696
3697<div class="doc_text">
3698
3699<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003700<pre>
3701 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3702</pre>
3703
3704<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003705<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +00003706 currently executing function, to be automatically released when this function
3707 returns to its caller. The object is always allocated in the generic address
3708 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003709
3710<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003711<p>The '<tt>alloca</tt>' instruction
3712 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3713 runtime stack, returning a pointer of the appropriate type to the program.
3714 If "NumElements" is specified, it is the number of elements allocated,
3715 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3716 specified, the value result of the allocation is guaranteed to be aligned to
3717 at least that boundary. If not specified, or if zero, the target can choose
3718 to align the allocation on any convenient boundary compatible with the
3719 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003720
3721<p>'<tt>type</tt>' may be any sized type.</p>
3722
3723<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +00003724<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +00003725 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3726 memory is automatically released when the function returns. The
3727 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3728 variables that must have an address available. When the function returns
3729 (either with the <tt><a href="#i_ret">ret</a></tt>
3730 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3731 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003732
3733<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003734<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +00003735 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3736 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3737 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3738 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003739</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003740
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003741</div>
3742
3743<!-- _______________________________________________________________________ -->
3744<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3745Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003746
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003747<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003748
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003749<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003750<pre>
3751 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3752 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3753</pre>
3754
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003755<h5>Overview:</h5>
3756<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003757
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003758<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003759<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3760 from which to load. The pointer must point to
3761 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3762 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3763 number or order of execution of this <tt>load</tt> with other
3764 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3765 instructions. </p>
3766
3767<p>The optional constant "align" argument specifies the alignment of the
3768 operation (that is, the alignment of the memory address). A value of 0 or an
3769 omitted "align" argument means that the operation has the preferential
3770 alignment for the target. It is the responsibility of the code emitter to
3771 ensure that the alignment information is correct. Overestimating the
3772 alignment results in an undefined behavior. Underestimating the alignment may
3773 produce less efficient code. An alignment of 1 is always safe.</p>
3774
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003775<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003776<p>The location of memory pointed to is loaded. If the value being loaded is of
3777 scalar type then the number of bytes read does not exceed the minimum number
3778 of bytes needed to hold all bits of the type. For example, loading an
3779 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3780 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3781 is undefined if the value was not originally written using a store of the
3782 same type.</p>
3783
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003784<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003785<pre>
3786 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3787 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003788 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3789</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003790
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003791</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003792
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003793<!-- _______________________________________________________________________ -->
3794<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3795Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003796
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003797<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003798
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003799<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003800<pre>
3801 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 +00003802 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3803</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003804
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003805<h5>Overview:</h5>
3806<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003807
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003808<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003809<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
3810 and an address at which to store it. The type of the
3811 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
3812 the <a href="#t_firstclass">first class</a> type of the
3813 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
3814 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
3815 or order of execution of this <tt>store</tt> with other
3816 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3817 instructions.</p>
3818
3819<p>The optional constant "align" argument specifies the alignment of the
3820 operation (that is, the alignment of the memory address). A value of 0 or an
3821 omitted "align" argument means that the operation has the preferential
3822 alignment for the target. It is the responsibility of the code emitter to
3823 ensure that the alignment information is correct. Overestimating the
3824 alignment results in an undefined behavior. Underestimating the alignment may
3825 produce less efficient code. An alignment of 1 is always safe.</p>
3826
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003827<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003828<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
3829 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
3830 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
3831 does not exceed the minimum number of bytes needed to hold all bits of the
3832 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
3833 writing a value of a type like <tt>i20</tt> with a size that is not an
3834 integral number of bytes, it is unspecified what happens to the extra bits
3835 that do not belong to the type, but they will typically be overwritten.</p>
3836
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003837<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003838<pre>
3839 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +00003840 store i32 3, i32* %ptr <i>; yields {void}</i>
3841 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003842</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003843
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003844</div>
3845
3846<!-- _______________________________________________________________________ -->
3847<div class="doc_subsubsection">
3848 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3849</div>
3850
3851<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003852
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003853<h5>Syntax:</h5>
3854<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +00003855 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003856</pre>
3857
3858<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003859<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
3860 subelement of an aggregate data structure. It performs address calculation
3861 only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003862
3863<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +00003864<p>The first argument is always a pointer, and forms the basis of the
Bill Wendlingf85859d2009-07-20 02:29:24 +00003865 calculation. The remaining arguments are indices, that indicate which of the
3866 elements of the aggregate object are indexed. The interpretation of each
3867 index is dependent on the type being indexed into. The first index always
3868 indexes the pointer value given as the first argument, the second index
3869 indexes a value of the type pointed to (not necessarily the value directly
3870 pointed to, since the first index can be non-zero), etc. The first type
3871 indexed into must be a pointer value, subsequent types can be arrays, vectors
3872 and structs. Note that subsequent types being indexed into can never be
3873 pointers, since that would require loading the pointer before continuing
3874 calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +00003875
3876<p>The type of each index argument depends on the type it is indexing into.
Bill Wendlingf85859d2009-07-20 02:29:24 +00003877 When indexing into a (packed) structure, only <tt>i32</tt> integer
3878 <b>constants</b> are allowed. When indexing into an array, pointer or
3879 vector, integers of any width are allowed (also non-constants).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003880
Bill Wendlingf85859d2009-07-20 02:29:24 +00003881<p>For example, let's consider a C code fragment and how it gets compiled to
3882 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003883
3884<div class="doc_code">
3885<pre>
3886struct RT {
3887 char A;
3888 int B[10][20];
3889 char C;
3890};
3891struct ST {
3892 int X;
3893 double Y;
3894 struct RT Z;
3895};
3896
3897int *foo(struct ST *s) {
3898 return &amp;s[1].Z.B[5][13];
3899}
3900</pre>
3901</div>
3902
3903<p>The LLVM code generated by the GCC frontend is:</p>
3904
3905<div class="doc_code">
3906<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +00003907%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3908%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003909
3910define i32* %foo(%ST* %s) {
3911entry:
3912 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3913 ret i32* %reg
3914}
3915</pre>
3916</div>
3917
3918<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003919<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +00003920 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3921 }</tt>' type, a structure. The second index indexes into the third element
3922 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3923 i8 }</tt>' type, another structure. The third index indexes into the second
3924 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3925 array. The two dimensions of the array are subscripted into, yielding an
3926 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
3927 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003928
Bill Wendlingf85859d2009-07-20 02:29:24 +00003929<p>Note that it is perfectly legal to index partially through a structure,
3930 returning a pointer to an inner element. Because of this, the LLVM code for
3931 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003932
3933<pre>
3934 define i32* %foo(%ST* %s) {
3935 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3936 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3937 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3938 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3939 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3940 ret i32* %t5
3941 }
3942</pre>
3943
Bill Wendlingf85859d2009-07-20 02:29:24 +00003944<p>The getelementptr instruction is often confusing. For some more insight into
3945 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003946
3947<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003948<pre>
3949 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +00003950 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3951 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +00003952 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman32a080e2008-10-13 13:44:15 +00003953 <i>; yields i8*:eptr</i>
3954 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +00003955 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +00003956 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003957</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003958
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003959</div>
3960
3961<!-- ======================================================================= -->
3962<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3963</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003964
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003965<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003966
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003967<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +00003968 which all take a single operand and a type. They perform various bit
3969 conversions on the operand.</p>
3970
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003971</div>
3972
3973<!-- _______________________________________________________________________ -->
3974<div class="doc_subsubsection">
3975 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3976</div>
3977<div class="doc_text">
3978
3979<h5>Syntax:</h5>
3980<pre>
3981 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3982</pre>
3983
3984<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003985<p>The '<tt>trunc</tt>' instruction truncates its operand to the
3986 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003987
3988<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003989<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3990 be an <a href="#t_integer">integer</a> type, and a type that specifies the
3991 size and type of the result, which must be
3992 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
3993 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
3994 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003995
3996<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003997<p>The '<tt>trunc</tt>' instruction truncates the high order bits
3998 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
3999 source size must be larger than the destination size, <tt>trunc</tt> cannot
4000 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004001
4002<h5>Example:</h5>
4003<pre>
4004 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4005 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4006 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
4007</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004008
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004009</div>
4010
4011<!-- _______________________________________________________________________ -->
4012<div class="doc_subsubsection">
4013 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4014</div>
4015<div class="doc_text">
4016
4017<h5>Syntax:</h5>
4018<pre>
4019 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4020</pre>
4021
4022<h5>Overview:</h5>
4023<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +00004024 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004025
4026
4027<h5>Arguments:</h5>
4028<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Bill Wendlingf85859d2009-07-20 02:29:24 +00004029 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4030 also be of <a href="#t_integer">integer</a> type. The bit size of the
4031 <tt>value</tt> must be smaller than the bit size of the destination type,
4032 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004033
4034<h5>Semantics:</h5>
4035<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlingf85859d2009-07-20 02:29:24 +00004036 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004037
4038<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4039
4040<h5>Example:</h5>
4041<pre>
4042 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4043 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4044</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004045
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004046</div>
4047
4048<!-- _______________________________________________________________________ -->
4049<div class="doc_subsubsection">
4050 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4051</div>
4052<div class="doc_text">
4053
4054<h5>Syntax:</h5>
4055<pre>
4056 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4057</pre>
4058
4059<h5>Overview:</h5>
4060<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4061
4062<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004063<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4064 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4065 also be of <a href="#t_integer">integer</a> type. The bit size of the
4066 <tt>value</tt> must be smaller than the bit size of the destination type,
4067 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004068
4069<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004070<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4071 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4072 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004073
4074<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4075
4076<h5>Example:</h5>
4077<pre>
4078 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4079 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4080</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004081
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004082</div>
4083
4084<!-- _______________________________________________________________________ -->
4085<div class="doc_subsubsection">
4086 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4087</div>
4088
4089<div class="doc_text">
4090
4091<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004092<pre>
4093 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4094</pre>
4095
4096<h5>Overview:</h5>
4097<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +00004098 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004099
4100<h5>Arguments:</h5>
4101<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +00004102 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4103 to cast it to. The size of <tt>value</tt> must be larger than the size of
4104 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4105 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004106
4107<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004108<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4109 <a href="#t_floating">floating point</a> type to a smaller
4110 <a href="#t_floating">floating point</a> type. If the value cannot fit
4111 within the destination type, <tt>ty2</tt>, then the results are
4112 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004113
4114<h5>Example:</h5>
4115<pre>
4116 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4117 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4118</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004119
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004120</div>
4121
4122<!-- _______________________________________________________________________ -->
4123<div class="doc_subsubsection">
4124 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4125</div>
4126<div class="doc_text">
4127
4128<h5>Syntax:</h5>
4129<pre>
4130 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4131</pre>
4132
4133<h5>Overview:</h5>
4134<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlingf85859d2009-07-20 02:29:24 +00004135 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004136
4137<h5>Arguments:</h5>
4138<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +00004139 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4140 a <a href="#t_floating">floating point</a> type to cast it to. The source
4141 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004142
4143<h5>Semantics:</h5>
4144<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +00004145 <a href="#t_floating">floating point</a> type to a larger
4146 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4147 used to make a <i>no-op cast</i> because it always changes bits. Use
4148 <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004149
4150<h5>Example:</h5>
4151<pre>
4152 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4153 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4154</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004155
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004156</div>
4157
4158<!-- _______________________________________________________________________ -->
4159<div class="doc_subsubsection">
4160 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4161</div>
4162<div class="doc_text">
4163
4164<h5>Syntax:</h5>
4165<pre>
Reid Spencere6adee82007-07-31 14:40:14 +00004166 &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 +00004167</pre>
4168
4169<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +00004170<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +00004171 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004172
4173<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004174<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4175 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4176 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4177 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4178 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004179
4180<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004181<p>The '<tt>fptoui</tt>' instruction converts its
4182 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4183 towards zero) unsigned integer value. If the value cannot fit
4184 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004185
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004186<h5>Example:</h5>
4187<pre>
Reid Spencere6adee82007-07-31 14:40:14 +00004188 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +00004189 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +00004190 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004191</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004192
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004193</div>
4194
4195<!-- _______________________________________________________________________ -->
4196<div class="doc_subsubsection">
4197 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4198</div>
4199<div class="doc_text">
4200
4201<h5>Syntax:</h5>
4202<pre>
4203 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4204</pre>
4205
4206<h5>Overview:</h5>
4207<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +00004208 <a href="#t_floating">floating point</a> <tt>value</tt> to
4209 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004210
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004211<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004212<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4213 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4214 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4215 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4216 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004217
4218<h5>Semantics:</h5>
4219<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +00004220 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4221 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4222 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004223
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004224<h5>Example:</h5>
4225<pre>
4226 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +00004227 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004228 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4229</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004230
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004231</div>
4232
4233<!-- _______________________________________________________________________ -->
4234<div class="doc_subsubsection">
4235 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4236</div>
4237<div class="doc_text">
4238
4239<h5>Syntax:</h5>
4240<pre>
4241 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4242</pre>
4243
4244<h5>Overview:</h5>
4245<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +00004246 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004247
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004248<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +00004249<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingf85859d2009-07-20 02:29:24 +00004250 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4251 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4252 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4253 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004254
4255<h5>Semantics:</h5>
4256<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +00004257 integer quantity and converts it to the corresponding floating point
4258 value. If the value cannot fit in the floating point value, the results are
4259 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004260
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004261<h5>Example:</h5>
4262<pre>
4263 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +00004264 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004265</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004266
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004267</div>
4268
4269<!-- _______________________________________________________________________ -->
4270<div class="doc_subsubsection">
4271 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4272</div>
4273<div class="doc_text">
4274
4275<h5>Syntax:</h5>
4276<pre>
4277 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4278</pre>
4279
4280<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004281<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4282 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004283
4284<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +00004285<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingf85859d2009-07-20 02:29:24 +00004286 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4287 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4288 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4289 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004290
4291<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004292<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4293 quantity and converts it to the corresponding floating point value. If the
4294 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004295
4296<h5>Example:</h5>
4297<pre>
4298 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +00004299 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004300</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004301
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004302</div>
4303
4304<!-- _______________________________________________________________________ -->
4305<div class="doc_subsubsection">
4306 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4307</div>
4308<div class="doc_text">
4309
4310<h5>Syntax:</h5>
4311<pre>
4312 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4313</pre>
4314
4315<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004316<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4317 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004318
4319<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004320<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4321 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4322 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004323
4324<h5>Semantics:</h5>
4325<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +00004326 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4327 truncating or zero extending that value to the size of the integer type. If
4328 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4329 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4330 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4331 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004332
4333<h5>Example:</h5>
4334<pre>
4335 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4336 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4337</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004338
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004339</div>
4340
4341<!-- _______________________________________________________________________ -->
4342<div class="doc_subsubsection">
4343 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4344</div>
4345<div class="doc_text">
4346
4347<h5>Syntax:</h5>
4348<pre>
4349 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4350</pre>
4351
4352<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004353<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4354 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004355
4356<h5>Arguments:</h5>
4357<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004358 value to cast, and a type to cast it to, which must be a
4359 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004360
4361<h5>Semantics:</h5>
4362<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +00004363 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4364 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4365 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4366 than the size of a pointer then a zero extension is done. If they are the
4367 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004368
4369<h5>Example:</h5>
4370<pre>
4371 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4372 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4373 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4374</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004375
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004376</div>
4377
4378<!-- _______________________________________________________________________ -->
4379<div class="doc_subsubsection">
4380 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4381</div>
4382<div class="doc_text">
4383
4384<h5>Syntax:</h5>
4385<pre>
4386 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4387</pre>
4388
4389<h5>Overview:</h5>
4390<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +00004391 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004392
4393<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004394<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4395 non-aggregate first class value, and a type to cast it to, which must also be
4396 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4397 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4398 identical. If the source type is a pointer, the destination type must also be
4399 a pointer. This instruction supports bitwise conversion of vectors to
4400 integers and to vectors of other types (as long as they have the same
4401 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004402
4403<h5>Semantics:</h5>
4404<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +00004405 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4406 this conversion. The conversion is done as if the <tt>value</tt> had been
4407 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4408 be converted to other pointer types with this instruction. To convert
4409 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4410 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004411
4412<h5>Example:</h5>
4413<pre>
4414 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4415 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +00004416 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004417</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004418
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004419</div>
4420
4421<!-- ======================================================================= -->
4422<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004423
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004424<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00004425
4426<p>The instructions in this category are the "miscellaneous" instructions, which
4427 defy better classification.</p>
4428
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004429</div>
4430
4431<!-- _______________________________________________________________________ -->
4432<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4433</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004434
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004435<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00004436
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004437<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004438<pre>
4439 &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 +00004440</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004441
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004442<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004443<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4444 boolean values based on comparison of its two integer, integer vector, or
4445 pointer operands.</p>
4446
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004447<h5>Arguments:</h5>
4448<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +00004449 the condition code indicating the kind of comparison to perform. It is not a
4450 value, just a keyword. The possible condition code are:</p>
4451
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004452<ol>
4453 <li><tt>eq</tt>: equal</li>
4454 <li><tt>ne</tt>: not equal </li>
4455 <li><tt>ugt</tt>: unsigned greater than</li>
4456 <li><tt>uge</tt>: unsigned greater or equal</li>
4457 <li><tt>ult</tt>: unsigned less than</li>
4458 <li><tt>ule</tt>: unsigned less or equal</li>
4459 <li><tt>sgt</tt>: signed greater than</li>
4460 <li><tt>sge</tt>: signed greater or equal</li>
4461 <li><tt>slt</tt>: signed less than</li>
4462 <li><tt>sle</tt>: signed less or equal</li>
4463</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004464
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004465<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +00004466 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4467 typed. They must also be identical types.</p>
4468
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004469<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004470<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4471 condition code given as <tt>cond</tt>. The comparison performed always yields
4472 either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt>
4473 result, as follows:</p>
4474
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004475<ol>
4476 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +00004477 <tt>false</tt> otherwise. No sign interpretation is necessary or
4478 performed.</li>
4479
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004480 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +00004481 <tt>false</tt> otherwise. No sign interpretation is necessary or
4482 performed.</li>
4483
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004484 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +00004485 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4486
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004487 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +00004488 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4489 to <tt>op2</tt>.</li>
4490
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004491 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +00004492 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4493
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004494 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +00004495 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4496
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004497 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +00004498 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4499
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004500 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +00004501 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4502 to <tt>op2</tt>.</li>
4503
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004504 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +00004505 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4506
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004507 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +00004508 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004509</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004510
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004511<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +00004512 values are compared as if they were integers.</p>
4513
4514<p>If the operands are integer vectors, then they are compared element by
4515 element. The result is an <tt>i1</tt> vector with the same number of elements
4516 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004517
4518<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004519<pre>
4520 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004521 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4522 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4523 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4524 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4525 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4526</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +00004527
4528<p>Note that the code generator does not yet support vector types with
4529 the <tt>icmp</tt> instruction.</p>
4530
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004531</div>
4532
4533<!-- _______________________________________________________________________ -->
4534<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4535</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004536
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004537<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00004538
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004539<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004540<pre>
4541 &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 +00004542</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004543
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004544<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004545<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4546 values based on comparison of its operands.</p>
4547
4548<p>If the operands are floating point scalars, then the result type is a boolean
4549(<a href="#t_primitive"><tt>i1</tt></a>).</p>
4550
4551<p>If the operands are floating point vectors, then the result type is a vector
4552 of boolean with the same number of elements as the operands being
4553 compared.</p>
4554
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004555<h5>Arguments:</h5>
4556<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +00004557 the condition code indicating the kind of comparison to perform. It is not a
4558 value, just a keyword. The possible condition code are:</p>
4559
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004560<ol>
4561 <li><tt>false</tt>: no comparison, always returns false</li>
4562 <li><tt>oeq</tt>: ordered and equal</li>
4563 <li><tt>ogt</tt>: ordered and greater than </li>
4564 <li><tt>oge</tt>: ordered and greater than or equal</li>
4565 <li><tt>olt</tt>: ordered and less than </li>
4566 <li><tt>ole</tt>: ordered and less than or equal</li>
4567 <li><tt>one</tt>: ordered and not equal</li>
4568 <li><tt>ord</tt>: ordered (no nans)</li>
4569 <li><tt>ueq</tt>: unordered or equal</li>
4570 <li><tt>ugt</tt>: unordered or greater than </li>
4571 <li><tt>uge</tt>: unordered or greater than or equal</li>
4572 <li><tt>ult</tt>: unordered or less than </li>
4573 <li><tt>ule</tt>: unordered or less than or equal</li>
4574 <li><tt>une</tt>: unordered or not equal</li>
4575 <li><tt>uno</tt>: unordered (either nans)</li>
4576 <li><tt>true</tt>: no comparison, always returns true</li>
4577</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004578
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004579<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +00004580 <i>unordered</i> means that either operand may be a QNAN.</p>
4581
4582<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4583 a <a href="#t_floating">floating point</a> type or
4584 a <a href="#t_vector">vector</a> of floating point type. They must have
4585 identical types.</p>
4586
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004587<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +00004588<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004589 according to the condition code given as <tt>cond</tt>. If the operands are
4590 vectors, then the vectors are compared element by element. Each comparison
4591 performed always yields an <a href="#t_primitive">i1</a> result, as
4592 follows:</p>
4593
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004594<ol>
4595 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004596
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004597 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +00004598 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4599
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004600 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +00004601 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4602
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004603 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +00004604 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4605
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004606 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +00004607 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4608
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004609 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +00004610 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4611
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004612 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +00004613 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4614
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004615 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004616
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004617 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +00004618 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4619
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004620 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +00004621 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4622
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004623 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +00004624 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4625
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004626 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +00004627 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4628
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004629 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +00004630 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4631
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004632 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +00004633 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4634
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004635 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004636
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004637 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4638</ol>
4639
4640<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004641<pre>
4642 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +00004643 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4644 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4645 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004646</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +00004647
4648<p>Note that the code generator does not yet support vector types with
4649 the <tt>fcmp</tt> instruction.</p>
4650
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004651</div>
4652
4653<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +00004654<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +00004655 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4656</div>
4657
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004658<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +00004659
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004660<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004661<pre>
4662 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4663</pre>
Chris Lattner6704c212008-05-20 20:48:21 +00004664
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004665<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004666<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4667 SSA graph representing the function.</p>
4668
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004669<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004670<p>The type of the incoming values is specified with the first type field. After
4671 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4672 one pair for each predecessor basic block of the current block. Only values
4673 of <a href="#t_firstclass">first class</a> type may be used as the value
4674 arguments to the PHI node. Only labels may be used as the label
4675 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00004676
Bill Wendlingf85859d2009-07-20 02:29:24 +00004677<p>There must be no non-phi instructions between the start of a basic block and
4678 the PHI instructions: i.e. PHI instructions must be first in a basic
4679 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00004680
Bill Wendlingf85859d2009-07-20 02:29:24 +00004681<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4682 occur on the edge from the corresponding predecessor block to the current
4683 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4684 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +00004685
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004686<h5>Semantics:</h5>
4687<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +00004688 specified by the pair corresponding to the predecessor basic block that
4689 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00004690
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004691<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00004692<pre>
4693Loop: ; Infinite loop that counts from 0 on up...
4694 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4695 %nextindvar = add i32 %indvar, 1
4696 br label %Loop
4697</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004698
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004699</div>
4700
4701<!-- _______________________________________________________________________ -->
4702<div class="doc_subsubsection">
4703 <a name="i_select">'<tt>select</tt>' Instruction</a>
4704</div>
4705
4706<div class="doc_text">
4707
4708<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004709<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +00004710 &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>
4711
Dan Gohman2672f3e2008-10-14 16:51:45 +00004712 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004713</pre>
4714
4715<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004716<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4717 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004718
4719
4720<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004721<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4722 values indicating the condition, and two values of the
4723 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4724 vectors and the condition is a scalar, then entire vectors are selected, not
4725 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004726
4727<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004728<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4729 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004730
Bill Wendlingf85859d2009-07-20 02:29:24 +00004731<p>If the condition is a vector of i1, then the value arguments must be vectors
4732 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004733
4734<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004735<pre>
4736 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4737</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +00004738
4739<p>Note that the code generator does not yet support conditions
4740 with vector type.</p>
4741
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004742</div>
4743
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004744<!-- _______________________________________________________________________ -->
4745<div class="doc_subsubsection">
4746 <a name="i_call">'<tt>call</tt>' Instruction</a>
4747</div>
4748
4749<div class="doc_text">
4750
4751<h5>Syntax:</h5>
4752<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +00004753 &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 +00004754</pre>
4755
4756<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004757<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4758
4759<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004760<p>This instruction requires several arguments:</p>
4761
4762<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004763 <li>The optional "tail" marker indicates whether the callee function accesses
4764 any allocas or varargs in the caller. If the "tail" marker is present,
4765 the function call is eligible for tail call optimization. Note that calls
4766 may be marked "tail" even if they do not occur before
4767 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelac2fc272008-10-06 18:50:38 +00004768
Bill Wendlingf85859d2009-07-20 02:29:24 +00004769 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4770 convention</a> the call should use. If none is specified, the call
4771 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +00004772
Bill Wendlingf85859d2009-07-20 02:29:24 +00004773 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4774 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4775 '<tt>inreg</tt>' attributes are valid here.</li>
4776
4777 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
4778 type of the return value. Functions that return no value are marked
4779 <tt><a href="#t_void">void</a></tt>.</li>
4780
4781 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
4782 being invoked. The argument types must match the types implied by this
4783 signature. This type can be omitted if the function is not varargs and if
4784 the function type does not return a pointer to a function.</li>
4785
4786 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4787 be invoked. In most cases, this is a direct function invocation, but
4788 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4789 to function value.</li>
4790
4791 <li>'<tt>function args</tt>': argument list whose types match the function
4792 signature argument types. All arguments must be of
4793 <a href="#t_firstclass">first class</a> type. If the function signature
4794 indicates the function accepts a variable number of arguments, the extra
4795 arguments can be specified.</li>
4796
4797 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
4798 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4799 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004800</ol>
4801
4802<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004803<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
4804 a specified function, with its incoming arguments bound to the specified
4805 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
4806 function, control flow continues with the instruction after the function
4807 call, and the return value of the function is bound to the result
4808 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004809
4810<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004811<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +00004812 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +00004813 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4814 %X = tail call i32 @foo() <i>; yields i32</i>
4815 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4816 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +00004817
4818 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +00004819 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +00004820 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4821 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +00004822 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +00004823 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004824</pre>
4825
4826</div>
4827
4828<!-- _______________________________________________________________________ -->
4829<div class="doc_subsubsection">
4830 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4831</div>
4832
4833<div class="doc_text">
4834
4835<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004836<pre>
4837 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4838</pre>
4839
4840<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004841<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +00004842 the "variable argument" area of a function call. It is used to implement the
4843 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004844
4845<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004846<p>This instruction takes a <tt>va_list*</tt> value and the type of the
4847 argument. It returns a value of the specified argument type and increments
4848 the <tt>va_list</tt> to point to the next argument. The actual type
4849 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004850
4851<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004852<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
4853 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
4854 to the next argument. For more information, see the variable argument
4855 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004856
4857<p>It is legal for this instruction to be called in a function which does not
Bill Wendlingf85859d2009-07-20 02:29:24 +00004858 take a variable number of arguments, for example, the <tt>vfprintf</tt>
4859 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004860
Bill Wendlingf85859d2009-07-20 02:29:24 +00004861<p><tt>va_arg</tt> is an LLVM instruction instead of
4862 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
4863 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004864
4865<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004866<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4867
Bill Wendlingf85859d2009-07-20 02:29:24 +00004868<p>Note that the code generator does not yet fully support va_arg on many
4869 targets. Also, it does not currently support va_arg with aggregate types on
4870 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +00004871
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004872</div>
4873
4874<!-- *********************************************************************** -->
4875<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4876<!-- *********************************************************************** -->
4877
4878<div class="doc_text">
4879
4880<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +00004881 well known names and semantics and are required to follow certain
4882 restrictions. Overall, these intrinsics represent an extension mechanism for
4883 the LLVM language that does not require changing all of the transformations
4884 in LLVM when adding to the language (or the bitcode reader/writer, the
4885 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004886
4887<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +00004888 prefix is reserved in LLVM for intrinsic names; thus, function names may not
4889 begin with this prefix. Intrinsic functions must always be external
4890 functions: you cannot define the body of intrinsic functions. Intrinsic
4891 functions may only be used in call or invoke instructions: it is illegal to
4892 take the address of an intrinsic function. Additionally, because intrinsic
4893 functions are part of the LLVM language, it is required if any are added that
4894 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004895
Bill Wendlingf85859d2009-07-20 02:29:24 +00004896<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
4897 family of functions that perform the same operation but on different data
4898 types. Because LLVM can represent over 8 million different integer types,
4899 overloading is used commonly to allow an intrinsic function to operate on any
4900 integer type. One or more of the argument types or the result type can be
4901 overloaded to accept any integer type. Argument types may also be defined as
4902 exactly matching a previous argument's type or the result type. This allows
4903 an intrinsic function which accepts multiple arguments, but needs all of them
4904 to be of the same type, to only be overloaded with respect to a single
4905 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004906
Bill Wendlingf85859d2009-07-20 02:29:24 +00004907<p>Overloaded intrinsics will have the names of its overloaded argument types
4908 encoded into its function name, each preceded by a period. Only those types
4909 which are overloaded result in a name suffix. Arguments whose type is matched
4910 against another type do not. For example, the <tt>llvm.ctpop</tt> function
4911 can take an integer of any width and returns an integer of exactly the same
4912 integer width. This leads to a family of functions such as
4913 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
4914 %val)</tt>. Only one type, the return type, is overloaded, and only one type
4915 suffix is required. Because the argument's type is matched against the return
4916 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004917
4918<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +00004919 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004920
4921</div>
4922
4923<!-- ======================================================================= -->
4924<div class="doc_subsection">
4925 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4926</div>
4927
4928<div class="doc_text">
4929
Bill Wendlingf85859d2009-07-20 02:29:24 +00004930<p>Variable argument support is defined in LLVM with
4931 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4932 intrinsic functions. These functions are related to the similarly named
4933 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004934
Bill Wendlingf85859d2009-07-20 02:29:24 +00004935<p>All of these functions operate on arguments that use a target-specific value
4936 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
4937 not define what this type is, so all transformations should be prepared to
4938 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004939
4940<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004941 instruction and the variable argument handling intrinsic functions are
4942 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004943
4944<div class="doc_code">
4945<pre>
4946define i32 @test(i32 %X, ...) {
4947 ; Initialize variable argument processing
4948 %ap = alloca i8*
4949 %ap2 = bitcast i8** %ap to i8*
4950 call void @llvm.va_start(i8* %ap2)
4951
4952 ; Read a single integer argument
4953 %tmp = va_arg i8** %ap, i32
4954
4955 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4956 %aq = alloca i8*
4957 %aq2 = bitcast i8** %aq to i8*
4958 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4959 call void @llvm.va_end(i8* %aq2)
4960
4961 ; Stop processing of arguments.
4962 call void @llvm.va_end(i8* %ap2)
4963 ret i32 %tmp
4964}
4965
4966declare void @llvm.va_start(i8*)
4967declare void @llvm.va_copy(i8*, i8*)
4968declare void @llvm.va_end(i8*)
4969</pre>
4970</div>
4971
4972</div>
4973
4974<!-- _______________________________________________________________________ -->
4975<div class="doc_subsubsection">
4976 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4977</div>
4978
4979
4980<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00004981
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004982<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004983<pre>
4984 declare void %llvm.va_start(i8* &lt;arglist&gt;)
4985</pre>
4986
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004987<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004988<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
4989 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004990
4991<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +00004992<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004993
4994<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +00004995<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004996 macro available in C. In a target-dependent way, it initializes
4997 the <tt>va_list</tt> element to which the argument points, so that the next
4998 call to <tt>va_arg</tt> will produce the first variable argument passed to
4999 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5000 need to know the last argument of the function as the compiler can figure
5001 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005002
5003</div>
5004
5005<!-- _______________________________________________________________________ -->
5006<div class="doc_subsubsection">
5007 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5008</div>
5009
5010<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005011
Bill Wendlingf85859d2009-07-20 02:29:24 +00005012<h5>Syntax:</h5>
5013<pre>
5014 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5015</pre>
5016
5017<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005018<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +00005019 which has been initialized previously
5020 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5021 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005022
5023<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005024<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5025
5026<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005027<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005028 macro available in C. In a target-dependent way, it destroys
5029 the <tt>va_list</tt> element to which the argument points. Calls
5030 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5031 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5032 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005033
5034</div>
5035
5036<!-- _______________________________________________________________________ -->
5037<div class="doc_subsubsection">
5038 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5039</div>
5040
5041<div class="doc_text">
5042
5043<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005044<pre>
5045 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5046</pre>
5047
5048<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005049<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +00005050 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005051
5052<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005053<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlingf85859d2009-07-20 02:29:24 +00005054 The second argument is a pointer to a <tt>va_list</tt> element to copy
5055 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005056
5057<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005058<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005059 macro available in C. In a target-dependent way, it copies the
5060 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5061 element. This intrinsic is necessary because
5062 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5063 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005064
5065</div>
5066
5067<!-- ======================================================================= -->
5068<div class="doc_subsection">
5069 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5070</div>
5071
5072<div class="doc_text">
5073
Bill Wendlingf85859d2009-07-20 02:29:24 +00005074<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +00005075Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +00005076intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5077roots on the stack</a>, as well as garbage collector implementations that
5078require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5079barriers. Front-ends for type-safe garbage collected languages should generate
5080these intrinsics to make use of the LLVM garbage collectors. For more details,
5081see <a href="GarbageCollection.html">Accurate Garbage Collection with
5082LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +00005083
Bill Wendlingf85859d2009-07-20 02:29:24 +00005084<p>The garbage collection intrinsics only operate on objects in the generic
5085 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +00005086
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005087</div>
5088
5089<!-- _______________________________________________________________________ -->
5090<div class="doc_subsubsection">
5091 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5092</div>
5093
5094<div class="doc_text">
5095
5096<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005097<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +00005098 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005099</pre>
5100
5101<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005102<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlingf85859d2009-07-20 02:29:24 +00005103 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005104
5105<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005106<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +00005107 root pointer. The second pointer (which must be either a constant or a
5108 global value address) contains the meta-data to be associated with the
5109 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005110
5111<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +00005112<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlingf85859d2009-07-20 02:29:24 +00005113 location. At compile-time, the code generator generates information to allow
5114 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5115 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5116 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005117
5118</div>
5119
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005120<!-- _______________________________________________________________________ -->
5121<div class="doc_subsubsection">
5122 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5123</div>
5124
5125<div class="doc_text">
5126
5127<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005128<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +00005129 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005130</pre>
5131
5132<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005133<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +00005134 locations, allowing garbage collector implementations that require read
5135 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005136
5137<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005138<p>The second argument is the address to read from, which should be an address
Bill Wendlingf85859d2009-07-20 02:29:24 +00005139 allocated from the garbage collector. The first object is a pointer to the
5140 start of the referenced object, if needed by the language runtime (otherwise
5141 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005142
5143<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005144<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +00005145 instruction, but may be replaced with substantially more complex code by the
5146 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5147 may only be used in a function which <a href="#gc">specifies a GC
5148 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005149
5150</div>
5151
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005152<!-- _______________________________________________________________________ -->
5153<div class="doc_subsubsection">
5154 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5155</div>
5156
5157<div class="doc_text">
5158
5159<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005160<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +00005161 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005162</pre>
5163
5164<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005165<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +00005166 locations, allowing garbage collector implementations that require write
5167 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005168
5169<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005170<p>The first argument is the reference to store, the second is the start of the
Bill Wendlingf85859d2009-07-20 02:29:24 +00005171 object to store it to, and the third is the address of the field of Obj to
5172 store to. If the runtime does not require a pointer to the object, Obj may
5173 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005174
5175<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005176<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +00005177 instruction, but may be replaced with substantially more complex code by the
5178 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5179 may only be used in a function which <a href="#gc">specifies a GC
5180 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005181
5182</div>
5183
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005184<!-- ======================================================================= -->
5185<div class="doc_subsection">
5186 <a name="int_codegen">Code Generator Intrinsics</a>
5187</div>
5188
5189<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00005190
5191<p>These intrinsics are provided by LLVM to expose special features that may
5192 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005193
5194</div>
5195
5196<!-- _______________________________________________________________________ -->
5197<div class="doc_subsubsection">
5198 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5199</div>
5200
5201<div class="doc_text">
5202
5203<h5>Syntax:</h5>
5204<pre>
5205 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5206</pre>
5207
5208<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005209<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5210 target-specific value indicating the return address of the current function
5211 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005212
5213<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005214<p>The argument to this intrinsic indicates which function to return the address
5215 for. Zero indicates the calling function, one indicates its caller, etc.
5216 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005217
5218<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005219<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5220 indicating the return address of the specified call frame, or zero if it
5221 cannot be identified. The value returned by this intrinsic is likely to be
5222 incorrect or 0 for arguments other than zero, so it should only be used for
5223 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005224
Bill Wendlingf85859d2009-07-20 02:29:24 +00005225<p>Note that calling this intrinsic does not prevent function inlining or other
5226 aggressive transformations, so the value returned may not be that of the
5227 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005228
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005229</div>
5230
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005231<!-- _______________________________________________________________________ -->
5232<div class="doc_subsubsection">
5233 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5234</div>
5235
5236<div class="doc_text">
5237
5238<h5>Syntax:</h5>
5239<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +00005240 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005241</pre>
5242
5243<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005244<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5245 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005246
5247<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005248<p>The argument to this intrinsic indicates which function to return the frame
5249 pointer for. Zero indicates the calling function, one indicates its caller,
5250 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005251
5252<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005253<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5254 indicating the frame address of the specified call frame, or zero if it
5255 cannot be identified. The value returned by this intrinsic is likely to be
5256 incorrect or 0 for arguments other than zero, so it should only be used for
5257 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005258
Bill Wendlingf85859d2009-07-20 02:29:24 +00005259<p>Note that calling this intrinsic does not prevent function inlining or other
5260 aggressive transformations, so the value returned may not be that of the
5261 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005262
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005263</div>
5264
5265<!-- _______________________________________________________________________ -->
5266<div class="doc_subsubsection">
5267 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5268</div>
5269
5270<div class="doc_text">
5271
5272<h5>Syntax:</h5>
5273<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +00005274 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005275</pre>
5276
5277<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005278<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5279 of the function stack, for use
5280 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5281 useful for implementing language features like scoped automatic variable
5282 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005283
5284<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005285<p>This intrinsic returns a opaque pointer value that can be passed
5286 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5287 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5288 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5289 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5290 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5291 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005292
5293</div>
5294
5295<!-- _______________________________________________________________________ -->
5296<div class="doc_subsubsection">
5297 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5298</div>
5299
5300<div class="doc_text">
5301
5302<h5>Syntax:</h5>
5303<pre>
5304 declare void @llvm.stackrestore(i8 * %ptr)
5305</pre>
5306
5307<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005308<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5309 the function stack to the state it was in when the
5310 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5311 executed. This is useful for implementing language features like scoped
5312 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005313
5314<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005315<p>See the description
5316 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005317
5318</div>
5319
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005320<!-- _______________________________________________________________________ -->
5321<div class="doc_subsubsection">
5322 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5323</div>
5324
5325<div class="doc_text">
5326
5327<h5>Syntax:</h5>
5328<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +00005329 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005330</pre>
5331
5332<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005333<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5334 insert a prefetch instruction if supported; otherwise, it is a noop.
5335 Prefetches have no effect on the behavior of the program but can change its
5336 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005337
5338<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005339<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5340 specifier determining if the fetch should be for a read (0) or write (1),
5341 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5342 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5343 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005344
5345<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005346<p>This intrinsic does not modify the behavior of the program. In particular,
5347 prefetches cannot trap and do not produce a value. On targets that support
5348 this intrinsic, the prefetch can provide hints to the processor cache for
5349 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005350
5351</div>
5352
5353<!-- _______________________________________________________________________ -->
5354<div class="doc_subsubsection">
5355 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5356</div>
5357
5358<div class="doc_text">
5359
5360<h5>Syntax:</h5>
5361<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +00005362 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005363</pre>
5364
5365<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005366<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5367 Counter (PC) in a region of code to simulators and other tools. The method
5368 is target specific, but it is expected that the marker will use exported
5369 symbols to transmit the PC of the marker. The marker makes no guarantees
5370 that it will remain with any specific instruction after optimizations. It is
5371 possible that the presence of a marker will inhibit optimizations. The
5372 intended use is to be inserted after optimizations to allow correlations of
5373 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005374
5375<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005376<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005377
5378<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005379<p>This intrinsic does not modify the behavior of the program. Backends that do
5380 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005381
5382</div>
5383
5384<!-- _______________________________________________________________________ -->
5385<div class="doc_subsubsection">
5386 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5387</div>
5388
5389<div class="doc_text">
5390
5391<h5>Syntax:</h5>
5392<pre>
5393 declare i64 @llvm.readcyclecounter( )
5394</pre>
5395
5396<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005397<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5398 counter register (or similar low latency, high accuracy clocks) on those
5399 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5400 should map to RPCC. As the backing counters overflow quickly (on the order
5401 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005402
5403<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005404<p>When directly supported, reading the cycle counter should not modify any
5405 memory. Implementations are allowed to either return a application specific
5406 value or a system wide value. On backends without support, this is lowered
5407 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005408
5409</div>
5410
5411<!-- ======================================================================= -->
5412<div class="doc_subsection">
5413 <a name="int_libc">Standard C Library Intrinsics</a>
5414</div>
5415
5416<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00005417
5418<p>LLVM provides intrinsics for a few important standard C library functions.
5419 These intrinsics allow source-language front-ends to pass information about
5420 the alignment of the pointer arguments to the code generator, providing
5421 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005422
5423</div>
5424
5425<!-- _______________________________________________________________________ -->
5426<div class="doc_subsubsection">
5427 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5428</div>
5429
5430<div class="doc_text">
5431
5432<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005433<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5434 integer bit width. Not all targets support all bit widths however.</p>
5435
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005436<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +00005437 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +00005438 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +00005439 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5440 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005441 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5442 i32 &lt;len&gt;, i32 &lt;align&gt;)
5443 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5444 i64 &lt;len&gt;, i32 &lt;align&gt;)
5445</pre>
5446
5447<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005448<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5449 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005450
Bill Wendlingf85859d2009-07-20 02:29:24 +00005451<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5452 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005453
5454<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005455<p>The first argument is a pointer to the destination, the second is a pointer
5456 to the source. The third argument is an integer argument specifying the
5457 number of bytes to copy, and the fourth argument is the alignment of the
5458 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005459
Bill Wendlingf85859d2009-07-20 02:29:24 +00005460<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5461 then the caller guarantees that both the source and destination pointers are
5462 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005463
5464<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005465<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5466 source location to the destination location, which are not allowed to
5467 overlap. It copies "len" bytes of memory over. If the argument is known to
5468 be aligned to some boundary, this can be specified as the fourth argument,
5469 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005470
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005471</div>
5472
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005473<!-- _______________________________________________________________________ -->
5474<div class="doc_subsubsection">
5475 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5476</div>
5477
5478<div class="doc_text">
5479
5480<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +00005481<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +00005482 width. Not all targets support all bit widths however.</p>
5483
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005484<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +00005485 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +00005486 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +00005487 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5488 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005489 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5490 i32 &lt;len&gt;, i32 &lt;align&gt;)
5491 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5492 i64 &lt;len&gt;, i32 &lt;align&gt;)
5493</pre>
5494
5495<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005496<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5497 source location to the destination location. It is similar to the
5498 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5499 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005500
Bill Wendlingf85859d2009-07-20 02:29:24 +00005501<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5502 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005503
5504<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005505<p>The first argument is a pointer to the destination, the second is a pointer
5506 to the source. The third argument is an integer argument specifying the
5507 number of bytes to copy, and the fourth argument is the alignment of the
5508 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005509
Bill Wendlingf85859d2009-07-20 02:29:24 +00005510<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5511 then the caller guarantees that the source and destination pointers are
5512 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005513
5514<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005515<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5516 source location to the destination location, which may overlap. It copies
5517 "len" bytes of memory over. If the argument is known to be aligned to some
5518 boundary, this can be specified as the fourth argument, otherwise it should
5519 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005520
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005521</div>
5522
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005523<!-- _______________________________________________________________________ -->
5524<div class="doc_subsubsection">
5525 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5526</div>
5527
5528<div class="doc_text">
5529
5530<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +00005531<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +00005532 width. Not all targets support all bit widths however.</p>
5533
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005534<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +00005535 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +00005536 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +00005537 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5538 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005539 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5540 i32 &lt;len&gt;, i32 &lt;align&gt;)
5541 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5542 i64 &lt;len&gt;, i32 &lt;align&gt;)
5543</pre>
5544
5545<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005546<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5547 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005548
Bill Wendlingf85859d2009-07-20 02:29:24 +00005549<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5550 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005551
5552<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005553<p>The first argument is a pointer to the destination to fill, the second is the
5554 byte value to fill it with, the third argument is an integer argument
5555 specifying the number of bytes to fill, and the fourth argument is the known
5556 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005557
Bill Wendlingf85859d2009-07-20 02:29:24 +00005558<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5559 then the caller guarantees that the destination pointer is aligned to that
5560 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005561
5562<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005563<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5564 at the destination location. If the argument is known to be aligned to some
5565 boundary, this can be specified as the fourth argument, otherwise it should
5566 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005567
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005568</div>
5569
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005570<!-- _______________________________________________________________________ -->
5571<div class="doc_subsubsection">
5572 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5573</div>
5574
5575<div class="doc_text">
5576
5577<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005578<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5579 floating point or vector of floating point type. Not all targets support all
5580 types however.</p>
5581
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005582<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +00005583 declare float @llvm.sqrt.f32(float %Val)
5584 declare double @llvm.sqrt.f64(double %Val)
5585 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5586 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5587 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005588</pre>
5589
5590<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005591<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5592 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5593 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5594 behavior for negative numbers other than -0.0 (which allows for better
5595 optimization, because there is no need to worry about errno being
5596 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005597
5598<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005599<p>The argument and return value are floating point numbers of the same
5600 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005601
5602<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005603<p>This function returns the sqrt of the specified operand if it is a
5604 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005605
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005606</div>
5607
5608<!-- _______________________________________________________________________ -->
5609<div class="doc_subsubsection">
5610 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5611</div>
5612
5613<div class="doc_text">
5614
5615<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005616<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5617 floating point or vector of floating point type. Not all targets support all
5618 types however.</p>
5619
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005620<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +00005621 declare float @llvm.powi.f32(float %Val, i32 %power)
5622 declare double @llvm.powi.f64(double %Val, i32 %power)
5623 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5624 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5625 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005626</pre>
5627
5628<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005629<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5630 specified (positive or negative) power. The order of evaluation of
5631 multiplications is not defined. When a vector of floating point type is
5632 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005633
5634<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005635<p>The second argument is an integer power, and the first is a value to raise to
5636 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005637
5638<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005639<p>This function returns the first value raised to the second power with an
5640 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005641
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005642</div>
5643
Dan Gohman361079c2007-10-15 20:30:11 +00005644<!-- _______________________________________________________________________ -->
5645<div class="doc_subsubsection">
5646 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5647</div>
5648
5649<div class="doc_text">
5650
5651<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005652<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5653 floating point or vector of floating point type. Not all targets support all
5654 types however.</p>
5655
Dan Gohman361079c2007-10-15 20:30:11 +00005656<pre>
5657 declare float @llvm.sin.f32(float %Val)
5658 declare double @llvm.sin.f64(double %Val)
5659 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5660 declare fp128 @llvm.sin.f128(fp128 %Val)
5661 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5662</pre>
5663
5664<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005665<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005666
5667<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005668<p>The argument and return value are floating point numbers of the same
5669 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005670
5671<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005672<p>This function returns the sine of the specified operand, returning the same
5673 values as the libm <tt>sin</tt> functions would, and handles error conditions
5674 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005675
Dan Gohman361079c2007-10-15 20:30:11 +00005676</div>
5677
5678<!-- _______________________________________________________________________ -->
5679<div class="doc_subsubsection">
5680 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5681</div>
5682
5683<div class="doc_text">
5684
5685<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005686<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5687 floating point or vector of floating point type. Not all targets support all
5688 types however.</p>
5689
Dan Gohman361079c2007-10-15 20:30:11 +00005690<pre>
5691 declare float @llvm.cos.f32(float %Val)
5692 declare double @llvm.cos.f64(double %Val)
5693 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5694 declare fp128 @llvm.cos.f128(fp128 %Val)
5695 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5696</pre>
5697
5698<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005699<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005700
5701<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005702<p>The argument and return value are floating point numbers of the same
5703 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005704
5705<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005706<p>This function returns the cosine of the specified operand, returning the same
5707 values as the libm <tt>cos</tt> functions would, and handles error conditions
5708 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005709
Dan Gohman361079c2007-10-15 20:30:11 +00005710</div>
5711
5712<!-- _______________________________________________________________________ -->
5713<div class="doc_subsubsection">
5714 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5715</div>
5716
5717<div class="doc_text">
5718
5719<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005720<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5721 floating point or vector of floating point type. Not all targets support all
5722 types however.</p>
5723
Dan Gohman361079c2007-10-15 20:30:11 +00005724<pre>
5725 declare float @llvm.pow.f32(float %Val, float %Power)
5726 declare double @llvm.pow.f64(double %Val, double %Power)
5727 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5728 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5729 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5730</pre>
5731
5732<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005733<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5734 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005735
5736<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005737<p>The second argument is a floating point power, and the first is a value to
5738 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005739
5740<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005741<p>This function returns the first value raised to the second power, returning
5742 the same values as the libm <tt>pow</tt> functions would, and handles error
5743 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005744
Dan Gohman361079c2007-10-15 20:30:11 +00005745</div>
5746
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005747<!-- ======================================================================= -->
5748<div class="doc_subsection">
5749 <a name="int_manip">Bit Manipulation Intrinsics</a>
5750</div>
5751
5752<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00005753
5754<p>LLVM provides intrinsics for a few important bit manipulation operations.
5755 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005756
5757</div>
5758
5759<!-- _______________________________________________________________________ -->
5760<div class="doc_subsubsection">
5761 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5762</div>
5763
5764<div class="doc_text">
5765
5766<h5>Syntax:</h5>
5767<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +00005768 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5769
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005770<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +00005771 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5772 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5773 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005774</pre>
5775
5776<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005777<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5778 values with an even number of bytes (positive multiple of 16 bits). These
5779 are useful for performing operations on data that is not in the target's
5780 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005781
5782<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005783<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
5784 and low byte of the input i16 swapped. Similarly,
5785 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
5786 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
5787 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
5788 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
5789 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
5790 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005791
5792</div>
5793
5794<!-- _______________________________________________________________________ -->
5795<div class="doc_subsubsection">
5796 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5797</div>
5798
5799<div class="doc_text">
5800
5801<h5>Syntax:</h5>
5802<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +00005803 width. Not all targets support all bit widths however.</p>
5804
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005805<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005806 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +00005807 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005808 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +00005809 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5810 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005811</pre>
5812
5813<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005814<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
5815 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005816
5817<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005818<p>The only argument is the value to be counted. The argument may be of any
5819 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005820
5821<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005822<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005823
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005824</div>
5825
5826<!-- _______________________________________________________________________ -->
5827<div class="doc_subsubsection">
5828 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5829</div>
5830
5831<div class="doc_text">
5832
5833<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005834<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5835 integer bit width. Not all targets support all bit widths however.</p>
5836
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005837<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +00005838 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5839 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005840 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +00005841 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5842 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005843</pre>
5844
5845<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005846<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5847 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005848
5849<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005850<p>The only argument is the value to be counted. The argument may be of any
5851 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005852
5853<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005854<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
5855 zeros in a variable. If the src == 0 then the result is the size in bits of
5856 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005857
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005858</div>
5859
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005860<!-- _______________________________________________________________________ -->
5861<div class="doc_subsubsection">
5862 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5863</div>
5864
5865<div class="doc_text">
5866
5867<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005868<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5869 integer bit width. Not all targets support all bit widths however.</p>
5870
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005871<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +00005872 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5873 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005874 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +00005875 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5876 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005877</pre>
5878
5879<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005880<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5881 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005882
5883<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005884<p>The only argument is the value to be counted. The argument may be of any
5885 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005886
5887<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005888<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
5889 zeros in a variable. If the src == 0 then the result is the size in bits of
5890 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005891
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005892</div>
5893
Bill Wendling3e1258b2009-02-08 04:04:40 +00005894<!-- ======================================================================= -->
5895<div class="doc_subsection">
5896 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
5897</div>
5898
5899<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00005900
5901<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +00005902
5903</div>
5904
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005905<!-- _______________________________________________________________________ -->
5906<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +00005907 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005908</div>
5909
5910<div class="doc_text">
5911
5912<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005913<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005914 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005915
5916<pre>
5917 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
5918 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5919 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
5920</pre>
5921
5922<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005923<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00005924 a signed addition of the two arguments, and indicate whether an overflow
5925 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005926
5927<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005928<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +00005929 be of integer types of any bit width, but they must have the same bit
5930 width. The second element of the result structure must be of
5931 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
5932 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005933
5934<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005935<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00005936 a signed addition of the two variables. They return a structure &mdash; the
5937 first element of which is the signed summation, and the second element of
5938 which is a bit specifying if the signed summation resulted in an
5939 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005940
5941<h5>Examples:</h5>
5942<pre>
5943 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5944 %sum = extractvalue {i32, i1} %res, 0
5945 %obit = extractvalue {i32, i1} %res, 1
5946 br i1 %obit, label %overflow, label %normal
5947</pre>
5948
5949</div>
5950
5951<!-- _______________________________________________________________________ -->
5952<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +00005953 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005954</div>
5955
5956<div class="doc_text">
5957
5958<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005959<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005960 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005961
5962<pre>
5963 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
5964 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
5965 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
5966</pre>
5967
5968<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005969<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00005970 an unsigned addition of the two arguments, and indicate whether a carry
5971 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005972
5973<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005974<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +00005975 be of integer types of any bit width, but they must have the same bit
5976 width. The second element of the result structure must be of
5977 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
5978 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005979
5980<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005981<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00005982 an unsigned addition of the two arguments. They return a structure &mdash;
5983 the first element of which is the sum, and the second element of which is a
5984 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005985
5986<h5>Examples:</h5>
5987<pre>
5988 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
5989 %sum = extractvalue {i32, i1} %res, 0
5990 %obit = extractvalue {i32, i1} %res, 1
5991 br i1 %obit, label %carry, label %normal
5992</pre>
5993
5994</div>
5995
5996<!-- _______________________________________________________________________ -->
5997<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +00005998 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005999</div>
6000
6001<div class="doc_text">
6002
6003<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006004<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006005 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006006
6007<pre>
6008 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6009 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6010 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6011</pre>
6012
6013<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006014<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006015 a signed subtraction of the two arguments, and indicate whether an overflow
6016 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006017
6018<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006019<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +00006020 be of integer types of any bit width, but they must have the same bit
6021 width. The second element of the result structure must be of
6022 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6023 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006024
6025<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006026<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006027 a signed subtraction of the two arguments. They return a structure &mdash;
6028 the first element of which is the subtraction, and the second element of
6029 which is a bit specifying if the signed subtraction resulted in an
6030 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006031
6032<h5>Examples:</h5>
6033<pre>
6034 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6035 %sum = extractvalue {i32, i1} %res, 0
6036 %obit = extractvalue {i32, i1} %res, 1
6037 br i1 %obit, label %overflow, label %normal
6038</pre>
6039
6040</div>
6041
6042<!-- _______________________________________________________________________ -->
6043<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +00006044 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006045</div>
6046
6047<div class="doc_text">
6048
6049<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006050<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006051 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006052
6053<pre>
6054 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6055 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6056 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6057</pre>
6058
6059<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006060<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006061 an unsigned subtraction of the two arguments, and indicate whether an
6062 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006063
6064<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006065<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +00006066 be of integer types of any bit width, but they must have the same bit
6067 width. The second element of the result structure must be of
6068 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6069 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006070
6071<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006072<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006073 an unsigned subtraction of the two arguments. They return a structure &mdash;
6074 the first element of which is the subtraction, and the second element of
6075 which is a bit specifying if the unsigned subtraction resulted in an
6076 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006077
6078<h5>Examples:</h5>
6079<pre>
6080 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6081 %sum = extractvalue {i32, i1} %res, 0
6082 %obit = extractvalue {i32, i1} %res, 1
6083 br i1 %obit, label %overflow, label %normal
6084</pre>
6085
6086</div>
6087
6088<!-- _______________________________________________________________________ -->
6089<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +00006090 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006091</div>
6092
6093<div class="doc_text">
6094
6095<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006096<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006097 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006098
6099<pre>
6100 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6101 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6102 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6103</pre>
6104
6105<h5>Overview:</h5>
6106
6107<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006108 a signed multiplication of the two arguments, and indicate whether an
6109 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006110
6111<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006112<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +00006113 be of integer types of any bit width, but they must have the same bit
6114 width. The second element of the result structure must be of
6115 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6116 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006117
6118<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006119<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006120 a signed multiplication of the two arguments. They return a structure &mdash;
6121 the first element of which is the multiplication, and the second element of
6122 which is a bit specifying if the signed multiplication resulted in an
6123 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006124
6125<h5>Examples:</h5>
6126<pre>
6127 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6128 %sum = extractvalue {i32, i1} %res, 0
6129 %obit = extractvalue {i32, i1} %res, 1
6130 br i1 %obit, label %overflow, label %normal
6131</pre>
6132
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006133</div>
6134
Bill Wendlingbda98b62009-02-08 23:00:09 +00006135<!-- _______________________________________________________________________ -->
6136<div class="doc_subsubsection">
6137 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6138</div>
6139
6140<div class="doc_text">
6141
6142<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006143<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006144 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006145
6146<pre>
6147 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6148 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6149 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6150</pre>
6151
6152<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006153<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006154 a unsigned multiplication of the two arguments, and indicate whether an
6155 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006156
6157<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006158<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +00006159 be of integer types of any bit width, but they must have the same bit
6160 width. The second element of the result structure must be of
6161 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6162 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006163
6164<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006165<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006166 an unsigned multiplication of the two arguments. They return a structure
6167 &mdash; the first element of which is the multiplication, and the second
6168 element of which is a bit specifying if the unsigned multiplication resulted
6169 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006170
6171<h5>Examples:</h5>
6172<pre>
6173 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6174 %sum = extractvalue {i32, i1} %res, 0
6175 %obit = extractvalue {i32, i1} %res, 1
6176 br i1 %obit, label %overflow, label %normal
6177</pre>
6178
6179</div>
6180
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006181<!-- ======================================================================= -->
6182<div class="doc_subsection">
6183 <a name="int_debugger">Debugger Intrinsics</a>
6184</div>
6185
6186<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006187
Bill Wendlingf85859d2009-07-20 02:29:24 +00006188<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6189 prefix), are described in
6190 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6191 Level Debugging</a> document.</p>
6192
6193</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006194
6195<!-- ======================================================================= -->
6196<div class="doc_subsection">
6197 <a name="int_eh">Exception Handling Intrinsics</a>
6198</div>
6199
6200<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006201
6202<p>The LLVM exception handling intrinsics (which all start with
6203 <tt>llvm.eh.</tt> prefix), are described in
6204 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6205 Handling</a> document.</p>
6206
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006207</div>
6208
6209<!-- ======================================================================= -->
6210<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +00006211 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +00006212</div>
6213
6214<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006215
6216<p>This intrinsic makes it possible to excise one parameter, marked with
6217 the <tt>nest</tt> attribute, from a function. The result is a callable
6218 function pointer lacking the nest parameter - the caller does not need to
6219 provide a value for it. Instead, the value to use is stored in advance in a
6220 "trampoline", a block of memory usually allocated on the stack, which also
6221 contains code to splice the nest value into the argument list. This is used
6222 to implement the GCC nested function address extension.</p>
6223
6224<p>For example, if the function is
6225 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6226 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6227 follows:</p>
6228
6229<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +00006230<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +00006231 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6232 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6233 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6234 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +00006235</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006236</div>
6237
6238<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6239 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6240
Duncan Sands38947cd2007-07-27 12:58:54 +00006241</div>
6242
6243<!-- _______________________________________________________________________ -->
6244<div class="doc_subsubsection">
6245 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6246</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006247
Duncan Sands38947cd2007-07-27 12:58:54 +00006248<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006249
Duncan Sands38947cd2007-07-27 12:58:54 +00006250<h5>Syntax:</h5>
6251<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006252 declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands38947cd2007-07-27 12:58:54 +00006253</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006254
Duncan Sands38947cd2007-07-27 12:58:54 +00006255<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006256<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6257 function pointer suitable for executing it.</p>
6258
Duncan Sands38947cd2007-07-27 12:58:54 +00006259<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006260<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6261 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6262 sufficiently aligned block of memory; this memory is written to by the
6263 intrinsic. Note that the size and the alignment are target-specific - LLVM
6264 currently provides no portable way of determining them, so a front-end that
6265 generates this intrinsic needs to have some target-specific knowledge.
6266 The <tt>func</tt> argument must hold a function bitcast to
6267 an <tt>i8*</tt>.</p>
6268
Duncan Sands38947cd2007-07-27 12:58:54 +00006269<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006270<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6271 dependent code, turning it into a function. A pointer to this function is
6272 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6273 function pointer type</a> before being called. The new function's signature
6274 is the same as that of <tt>func</tt> with any arguments marked with
6275 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6276 is allowed, and it must be of pointer type. Calling the new function is
6277 equivalent to calling <tt>func</tt> with the same argument list, but
6278 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6279 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6280 by <tt>tramp</tt> is modified, then the effect of any later call to the
6281 returned function pointer is undefined.</p>
6282
Duncan Sands38947cd2007-07-27 12:58:54 +00006283</div>
6284
6285<!-- ======================================================================= -->
6286<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +00006287 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6288</div>
6289
6290<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +00006291
Bill Wendlingf85859d2009-07-20 02:29:24 +00006292<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6293 hardware constructs for atomic operations and memory synchronization. This
6294 provides an interface to the hardware, not an interface to the programmer. It
6295 is aimed at a low enough level to allow any programming models or APIs
6296 (Application Programming Interfaces) which need atomic behaviors to map
6297 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6298 hardware provides a "universal IR" for source languages, it also provides a
6299 starting point for developing a "universal" atomic operation and
6300 synchronization IR.</p>
6301
6302<p>These do <em>not</em> form an API such as high-level threading libraries,
6303 software transaction memory systems, atomic primitives, and intrinsic
6304 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6305 application libraries. The hardware interface provided by LLVM should allow
6306 a clean implementation of all of these APIs and parallel programming models.
6307 No one model or paradigm should be selected above others unless the hardware
6308 itself ubiquitously does so.</p>
6309
Andrew Lenharth785610d2008-02-16 01:24:58 +00006310</div>
6311
6312<!-- _______________________________________________________________________ -->
6313<div class="doc_subsubsection">
6314 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6315</div>
6316<div class="doc_text">
6317<h5>Syntax:</h5>
6318<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006319 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 +00006320</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006321
Andrew Lenharth785610d2008-02-16 01:24:58 +00006322<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006323<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6324 specific pairs of memory access types.</p>
6325
Andrew Lenharth785610d2008-02-16 01:24:58 +00006326<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006327<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6328 The first four arguments enables a specific barrier as listed below. The
6329 fith argument specifies that the barrier applies to io or device or uncached
6330 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +00006331
Bill Wendlingf85859d2009-07-20 02:29:24 +00006332<ul>
6333 <li><tt>ll</tt>: load-load barrier</li>
6334 <li><tt>ls</tt>: load-store barrier</li>
6335 <li><tt>sl</tt>: store-load barrier</li>
6336 <li><tt>ss</tt>: store-store barrier</li>
6337 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6338</ul>
6339
Andrew Lenharth785610d2008-02-16 01:24:58 +00006340<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006341<p>This intrinsic causes the system to enforce some ordering constraints upon
6342 the loads and stores of the program. This barrier does not
6343 indicate <em>when</em> any events will occur, it only enforces
6344 an <em>order</em> in which they occur. For any of the specified pairs of load
6345 and store operations (f.ex. load-load, or store-load), all of the first
6346 operations preceding the barrier will complete before any of the second
6347 operations succeeding the barrier begin. Specifically the semantics for each
6348 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +00006349
Bill Wendlingf85859d2009-07-20 02:29:24 +00006350<ul>
6351 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6352 after the barrier begins.</li>
6353 <li><tt>ls</tt>: All loads before the barrier must complete before any
6354 store after the barrier begins.</li>
6355 <li><tt>ss</tt>: All stores before the barrier must complete before any
6356 store after the barrier begins.</li>
6357 <li><tt>sl</tt>: All stores before the barrier must complete before any
6358 load after the barrier begins.</li>
6359</ul>
6360
6361<p>These semantics are applied with a logical "and" behavior when more than one
6362 is enabled in a single memory barrier intrinsic.</p>
6363
6364<p>Backends may implement stronger barriers than those requested when they do
6365 not support as fine grained a barrier as requested. Some architectures do
6366 not need all types of barriers and on such architectures, these become
6367 noops.</p>
6368
Andrew Lenharth785610d2008-02-16 01:24:58 +00006369<h5>Example:</h5>
6370<pre>
6371%ptr = malloc i32
6372 store i32 4, %ptr
6373
6374%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6375 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6376 <i>; guarantee the above finishes</i>
6377 store i32 8, %ptr <i>; before this begins</i>
6378</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006379
Andrew Lenharth785610d2008-02-16 01:24:58 +00006380</div>
6381
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006382<!-- _______________________________________________________________________ -->
6383<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006384 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006385</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006386
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006387<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006388
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006389<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006390<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6391 any integer bit width and for different address spaces. Not all targets
6392 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006393
6394<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006395 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6396 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6397 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6398 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 +00006399</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006400
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006401<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006402<p>This loads a value in memory and compares it to a given value. If they are
6403 equal, it stores a new value into the memory.</p>
6404
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006405<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006406<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6407 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6408 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6409 this integer type. While any bit width integer may be used, targets may only
6410 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006411
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006412<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006413<p>This entire intrinsic must be executed atomically. It first loads the value
6414 in memory pointed to by <tt>ptr</tt> and compares it with the
6415 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6416 memory. The loaded value is yielded in all cases. This provides the
6417 equivalent of an atomic compare-and-swap operation within the SSA
6418 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006419
Bill Wendlingf85859d2009-07-20 02:29:24 +00006420<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006421<pre>
6422%ptr = malloc i32
6423 store i32 4, %ptr
6424
6425%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +00006426%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006427 <i>; yields {i32}:result1 = 4</i>
6428%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6429%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6430
6431%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +00006432%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006433 <i>; yields {i32}:result2 = 8</i>
6434%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6435
6436%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6437</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006438
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006439</div>
6440
6441<!-- _______________________________________________________________________ -->
6442<div class="doc_subsubsection">
6443 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6444</div>
6445<div class="doc_text">
6446<h5>Syntax:</h5>
6447
Bill Wendlingf85859d2009-07-20 02:29:24 +00006448<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6449 integer bit width. Not all targets support all bit widths however.</p>
6450
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006451<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006452 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6453 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6454 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6455 declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006456</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006457
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006458<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006459<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6460 the value from memory. It then stores the value in <tt>val</tt> in the memory
6461 at <tt>ptr</tt>.</p>
6462
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006463<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006464<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6465 the <tt>val</tt> argument and the result must be integers of the same bit
6466 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6467 integer type. The targets may only lower integer representations they
6468 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006469
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006470<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006471<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6472 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6473 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006474
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006475<h5>Examples:</h5>
6476<pre>
6477%ptr = malloc i32
6478 store i32 4, %ptr
6479
6480%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +00006481%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006482 <i>; yields {i32}:result1 = 4</i>
6483%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6484%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6485
6486%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +00006487%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006488 <i>; yields {i32}:result2 = 8</i>
6489
6490%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6491%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6492</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006493
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006494</div>
6495
6496<!-- _______________________________________________________________________ -->
6497<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006498 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006499
6500</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006501
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006502<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006503
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006504<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006505<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6506 any integer bit width. Not all targets support all bit widths however.</p>
6507
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006508<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006509 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6510 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6511 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6512 declare i64 @llvm.atomic.load.add.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006513</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006514
Bill Wendlingf85859d2009-07-20 02:29:24 +00006515<h5>Overview:</h5>
6516<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6517 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6518
6519<h5>Arguments:</h5>
6520<p>The intrinsic takes two arguments, the first a pointer to an integer value
6521 and the second an integer value. The result is also an integer value. These
6522 integer types can have any bit width, but they must all have the same bit
6523 width. The targets may only lower integer representations they support.</p>
6524
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006525<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006526<p>This intrinsic does a series of operations atomically. It first loads the
6527 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6528 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006529
6530<h5>Examples:</h5>
6531<pre>
6532%ptr = malloc i32
6533 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +00006534%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006535 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006536%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006537 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006538%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006539 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006540%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006541</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006542
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006543</div>
6544
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006545<!-- _______________________________________________________________________ -->
6546<div class="doc_subsubsection">
6547 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6548
6549</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006550
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006551<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006552
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006553<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006554<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6555 any integer bit width and for different address spaces. Not all targets
6556 support all bit widths however.</p>
6557
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006558<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006559 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6560 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6561 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6562 declare i64 @llvm.atomic.load.sub.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006563</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006564
Bill Wendlingf85859d2009-07-20 02:29:24 +00006565<h5>Overview:</h5>
6566<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6567 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6568
6569<h5>Arguments:</h5>
6570<p>The intrinsic takes two arguments, the first a pointer to an integer value
6571 and the second an integer value. The result is also an integer value. These
6572 integer types can have any bit width, but they must all have the same bit
6573 width. The targets may only lower integer representations they support.</p>
6574
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006575<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006576<p>This intrinsic does a series of operations atomically. It first loads the
6577 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6578 result to <tt>ptr</tt>. It yields the original value stored
6579 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006580
6581<h5>Examples:</h5>
6582<pre>
6583%ptr = malloc i32
6584 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +00006585%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006586 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006587%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006588 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006589%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006590 <i>; yields {i32}:result3 = 2</i>
6591%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6592</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006593
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006594</div>
6595
6596<!-- _______________________________________________________________________ -->
6597<div class="doc_subsubsection">
6598 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6599 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6600 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6601 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006602</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006603
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006604<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006605
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006606<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006607<p>These are overloaded intrinsics. You can
6608 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6609 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6610 bit width and for different address spaces. Not all targets support all bit
6611 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006612
Bill Wendlingf85859d2009-07-20 02:29:24 +00006613<pre>
6614 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6615 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6616 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6617 declare i64 @llvm.atomic.load.and.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006618</pre>
6619
6620<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006621 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6622 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6623 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6624 declare i64 @llvm.atomic.load.or.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006625</pre>
6626
6627<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006628 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6629 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6630 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6631 declare i64 @llvm.atomic.load.nand.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006632</pre>
6633
6634<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006635 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6636 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6637 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6638 declare i64 @llvm.atomic.load.xor.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006639</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006640
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006641<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006642<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6643 the value stored in memory at <tt>ptr</tt>. It yields the original value
6644 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006645
Bill Wendlingf85859d2009-07-20 02:29:24 +00006646<h5>Arguments:</h5>
6647<p>These intrinsics take two arguments, the first a pointer to an integer value
6648 and the second an integer value. The result is also an integer value. These
6649 integer types can have any bit width, but they must all have the same bit
6650 width. The targets may only lower integer representations they support.</p>
6651
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006652<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006653<p>These intrinsics does a series of operations atomically. They first load the
6654 value stored at <tt>ptr</tt>. They then do the bitwise
6655 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6656 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006657
6658<h5>Examples:</h5>
6659<pre>
6660%ptr = malloc i32
6661 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +00006662%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006663 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006664%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006665 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006666%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006667 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006668%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006669 <i>; yields {i32}:result3 = FF</i>
6670%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6671</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006672
Bill Wendlingf85859d2009-07-20 02:29:24 +00006673</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006674
6675<!-- _______________________________________________________________________ -->
6676<div class="doc_subsubsection">
6677 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6678 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6679 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6680 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006681</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006682
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006683<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006684
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006685<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006686<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6687 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6688 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6689 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006690
Bill Wendlingf85859d2009-07-20 02:29:24 +00006691<pre>
6692 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6693 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6694 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6695 declare i64 @llvm.atomic.load.max.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006696</pre>
6697
6698<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006699 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6700 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6701 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6702 declare i64 @llvm.atomic.load.min.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006703</pre>
6704
6705<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006706 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6707 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6708 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6709 declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006710</pre>
6711
6712<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006713 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6714 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6715 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6716 declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006717</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006718
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006719<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006720<p>These intrinsics takes the signed or unsigned minimum or maximum of
6721 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6722 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006723
Bill Wendlingf85859d2009-07-20 02:29:24 +00006724<h5>Arguments:</h5>
6725<p>These intrinsics take two arguments, the first a pointer to an integer value
6726 and the second an integer value. The result is also an integer value. These
6727 integer types can have any bit width, but they must all have the same bit
6728 width. The targets may only lower integer representations they support.</p>
6729
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006730<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006731<p>These intrinsics does a series of operations atomically. They first load the
6732 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6733 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6734 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006735
6736<h5>Examples:</h5>
6737<pre>
6738%ptr = malloc i32
6739 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +00006740%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006741 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006742%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006743 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006744%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006745 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006746%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006747 <i>; yields {i32}:result3 = 8</i>
6748%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6749</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006750
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006751</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +00006752
6753<!-- ======================================================================= -->
6754<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006755 <a name="int_general">General Intrinsics</a>
6756</div>
6757
6758<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006759
6760<p>This class of intrinsics is designed to be generic and has no specific
6761 purpose.</p>
6762
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006763</div>
6764
6765<!-- _______________________________________________________________________ -->
6766<div class="doc_subsubsection">
6767 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6768</div>
6769
6770<div class="doc_text">
6771
6772<h5>Syntax:</h5>
6773<pre>
6774 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6775</pre>
6776
6777<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006778<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006779
6780<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006781<p>The first argument is a pointer to a value, the second is a pointer to a
6782 global string, the third is a pointer to a global string which is the source
6783 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006784
6785<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006786<p>This intrinsic allows annotation of local variables with arbitrary strings.
6787 This can be useful for special purpose optimizations that want to look for
6788 these annotations. These have no other defined use, they are ignored by code
6789 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006790
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006791</div>
6792
Tanya Lattnerb306a9e2007-09-21 22:59:12 +00006793<!-- _______________________________________________________________________ -->
6794<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +00006795 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +00006796</div>
6797
6798<div class="doc_text">
6799
6800<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006801<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6802 any integer bit width.</p>
6803
Tanya Lattnerb306a9e2007-09-21 22:59:12 +00006804<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +00006805 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6806 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6807 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6808 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6809 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 +00006810</pre>
6811
6812<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006813<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +00006814
6815<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006816<p>The first argument is an integer value (result of some expression), the
6817 second is a pointer to a global string, the third is a pointer to a global
6818 string which is the source file name, and the last argument is the line
6819 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +00006820
6821<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006822<p>This intrinsic allows annotations to be put on arbitrary expressions with
6823 arbitrary strings. This can be useful for special purpose optimizations that
6824 want to look for these annotations. These have no other defined use, they
6825 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +00006826
Tanya Lattnerb306a9e2007-09-21 22:59:12 +00006827</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006828
Anton Korobeynikove6e764f2008-01-15 22:31:34 +00006829<!-- _______________________________________________________________________ -->
6830<div class="doc_subsubsection">
6831 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6832</div>
6833
6834<div class="doc_text">
6835
6836<h5>Syntax:</h5>
6837<pre>
6838 declare void @llvm.trap()
6839</pre>
6840
6841<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006842<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +00006843
6844<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006845<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +00006846
6847<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006848<p>This intrinsics is lowered to the target dependent trap instruction. If the
6849 target does not have a trap instruction, this intrinsic will be lowered to
6850 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +00006851
Anton Korobeynikove6e764f2008-01-15 22:31:34 +00006852</div>
6853
Bill Wendlinge4164592008-11-19 05:56:17 +00006854<!-- _______________________________________________________________________ -->
6855<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +00006856 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +00006857</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006858
Bill Wendlinge4164592008-11-19 05:56:17 +00006859<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006860
Bill Wendlinge4164592008-11-19 05:56:17 +00006861<h5>Syntax:</h5>
6862<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006863 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +00006864</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006865
Bill Wendlinge4164592008-11-19 05:56:17 +00006866<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006867<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
6868 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
6869 ensure that it is placed on the stack before local variables.</p>
6870
Bill Wendlinge4164592008-11-19 05:56:17 +00006871<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006872<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
6873 arguments. The first argument is the value loaded from the stack
6874 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
6875 that has enough space to hold the value of the guard.</p>
6876
Bill Wendlinge4164592008-11-19 05:56:17 +00006877<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006878<p>This intrinsic causes the prologue/epilogue inserter to force the position of
6879 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6880 stack. This is to ensure that if a local variable on the stack is
6881 overwritten, it will destroy the value of the guard. When the function exits,
6882 the guard on the stack is checked against the original guard. If they're
6883 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
6884 function.</p>
6885
Bill Wendlinge4164592008-11-19 05:56:17 +00006886</div>
6887
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006888<!-- *********************************************************************** -->
6889<hr>
6890<address>
6891 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +00006892 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006893 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +00006894 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006895
6896 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6897 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6898 Last modified: $Date$
6899</address>
Chris Lattner08497ce2008-01-04 04:33:49 +00006900
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006901</body>
6902</html>