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5 <title>LLVM Assembly Language Reference Manual</title>
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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>
2604 &lt;result&gt; = signed add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2605 &lt;result&gt; = unsigned add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman67fa48e2009-07-22 00:04:19 +00002606 &lt;result&gt; = unsigned signed 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 Gohmaned5fcb22009-07-20 22:41:19 +00002626<p>If the <tt>signed</tt> and/or <tt>unsigned</tt> keywords are present,
Dan Gohman67fa48e2009-07-22 00:04:19 +00002627 the result value of the <tt>add</tt> is undefined if signed and/or unsigned
Dan Gohmaned5fcb22009-07-20 22:41:19 +00002628 overflow, respectively, occurs.</p>
2629
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002630<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002631<pre>
2632 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002633</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002634
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002635</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002636
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002637<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +00002638<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +00002639 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2640</div>
2641
2642<div class="doc_text">
2643
2644<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002645<pre>
2646 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2647</pre>
2648
2649<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002650<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2651
2652<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002653<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002654 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2655 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002656
2657<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002658<p>The value produced is the floating point sum of the two operands.</p>
2659
2660<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002661<pre>
2662 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2663</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002664
Dan Gohman7ce405e2009-06-04 22:49:04 +00002665</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002666
Dan Gohman7ce405e2009-06-04 22:49:04 +00002667<!-- _______________________________________________________________________ -->
2668<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +00002669 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2670</div>
2671
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002672<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +00002673
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002674<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002675<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +00002676 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2677 &lt;result&gt; = signed sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2678 &lt;result&gt; = unsigned sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman67fa48e2009-07-22 00:04:19 +00002679 &lt;result&gt; = unsigned signed sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002680</pre>
Chris Lattner6704c212008-05-20 20:48:21 +00002681
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002682<h5>Overview:</h5>
2683<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +00002684 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002685
2686<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +00002687 '<tt>neg</tt>' instruction present in most other intermediate
2688 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002689
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002690<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002691<p>The two arguments to the '<tt>sub</tt>' instruction must
2692 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2693 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002694
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002695<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002696<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002697
Dan Gohman7ce405e2009-06-04 22:49:04 +00002698<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +00002699 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2700 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002701
Bill Wendlingf85859d2009-07-20 02:29:24 +00002702<p>Because LLVM integers use a two's complement representation, this instruction
2703 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002704
Dan Gohmaned5fcb22009-07-20 22:41:19 +00002705<p>If the <tt>signed</tt> and/or <tt>unsigned</tt> keywords are present,
Dan Gohman67fa48e2009-07-22 00:04:19 +00002706 the result value of the <tt>sub</tt> is undefined if signed and/or unsigned
Dan Gohmaned5fcb22009-07-20 22:41:19 +00002707 overflow, respectively, occurs.</p>
2708
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002709<h5>Example:</h5>
2710<pre>
2711 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2712 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2713</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002714
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002715</div>
Chris Lattner6704c212008-05-20 20:48:21 +00002716
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002717<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +00002718<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +00002719 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2720</div>
2721
2722<div class="doc_text">
2723
2724<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002725<pre>
2726 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2727</pre>
2728
2729<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002730<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +00002731 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002732
2733<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +00002734 '<tt>fneg</tt>' instruction present in most other intermediate
2735 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002736
2737<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +00002738<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002739 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2740 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002741
2742<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002743<p>The value produced is the floating point difference of the two operands.</p>
2744
2745<h5>Example:</h5>
2746<pre>
2747 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2748 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2749</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002750
Dan Gohman7ce405e2009-06-04 22:49:04 +00002751</div>
2752
2753<!-- _______________________________________________________________________ -->
2754<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +00002755 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2756</div>
2757
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002758<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +00002759
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002760<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002761<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +00002762 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2763 &lt;result&gt; = signed mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2764 &lt;result&gt; = unsigned mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman67fa48e2009-07-22 00:04:19 +00002765 &lt;result&gt; = unsigned signed mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002766</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002767
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002768<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002769<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002770
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002771<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002772<p>The two arguments to the '<tt>mul</tt>' instruction must
2773 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2774 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002775
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002776<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002777<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002778
Bill Wendlingf85859d2009-07-20 02:29:24 +00002779<p>If the result of the multiplication has unsigned overflow, the result
2780 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
2781 width of the result.</p>
2782
2783<p>Because LLVM integers use a two's complement representation, and the result
2784 is the same width as the operands, this instruction returns the correct
2785 result for both signed and unsigned integers. If a full product
2786 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
2787 be sign-extended or zero-extended as appropriate to the width of the full
2788 product.</p>
2789
Dan Gohmaned5fcb22009-07-20 22:41:19 +00002790<p>If the <tt>signed</tt> and/or <tt>unsigned</tt> keywords are present,
Dan Gohman67fa48e2009-07-22 00:04:19 +00002791 the result value of the <tt>mul</tt> is undefined if signed and/or unsigned
Dan Gohmaned5fcb22009-07-20 22:41:19 +00002792 overflow, respectively, occurs.</p>
2793
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002794<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002795<pre>
2796 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002797</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002798
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002799</div>
Chris Lattner6704c212008-05-20 20:48:21 +00002800
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002801<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +00002802<div class="doc_subsubsection">
2803 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
2804</div>
2805
2806<div class="doc_text">
2807
2808<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002809<pre>
2810 &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 +00002811</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002812
Dan Gohman7ce405e2009-06-04 22:49:04 +00002813<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002814<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002815
2816<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002817<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002818 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2819 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002820
2821<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002822<p>The value produced is the floating point product of the two operands.</p>
2823
2824<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002825<pre>
2826 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohman7ce405e2009-06-04 22:49:04 +00002827</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002828
Dan Gohman7ce405e2009-06-04 22:49:04 +00002829</div>
2830
2831<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002832<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2833</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002834
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002835<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00002836
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002837<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002838<pre>
2839 &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 +00002840</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002841
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002842<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002843<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002844
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002845<h5>Arguments:</h5>
2846<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002847 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2848 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002849
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002850<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +00002851<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002852
Chris Lattner9aba1e22008-01-28 00:36:27 +00002853<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +00002854 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2855
Chris Lattner9aba1e22008-01-28 00:36:27 +00002856<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002857
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002858<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002859<pre>
2860 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002861</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002862
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002863</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002864
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002865<!-- _______________________________________________________________________ -->
2866<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2867</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002868
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002869<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00002870
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002871<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002872<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +00002873 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2874 &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 +00002875</pre>
Chris Lattner6704c212008-05-20 20:48:21 +00002876
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002877<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002878<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002879
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002880<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002881<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002882 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2883 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002884
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002885<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002886<p>The value produced is the signed integer quotient of the two operands rounded
2887 towards zero.</p>
2888
Chris Lattner9aba1e22008-01-28 00:36:27 +00002889<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +00002890 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2891
Chris Lattner9aba1e22008-01-28 00:36:27 +00002892<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +00002893 undefined behavior; this is a rare case, but can occur, for example, by doing
2894 a 32-bit division of -2147483648 by -1.</p>
2895
Dan Gohman67fa48e2009-07-22 00:04:19 +00002896<p>If the <tt>exact</tt> keyword is present, the result value of the
2897 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
2898 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +00002899
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002900<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002901<pre>
2902 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002903</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002904
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002905</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002906
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002907<!-- _______________________________________________________________________ -->
2908<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2909Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002910
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002911<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00002912
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002913<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002914<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +00002915 &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 +00002916</pre>
Chris Lattner6704c212008-05-20 20:48:21 +00002917
Bill Wendlingf85859d2009-07-20 02:29:24 +00002918<h5>Overview:</h5>
2919<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002920
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002921<h5>Arguments:</h5>
2922<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002923 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2924 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002925
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002926<h5>Semantics:</h5>
2927<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002928
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002929<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002930<pre>
2931 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002932</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002933
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002934</div>
Chris Lattner6704c212008-05-20 20:48:21 +00002935
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002936<!-- _______________________________________________________________________ -->
2937<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2938</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002939
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002940<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00002941
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002942<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002943<pre>
2944 &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 +00002945</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002946
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002947<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002948<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
2949 division of its two arguments.</p>
2950
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002951<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002952<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002953 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2954 values. Both arguments must have identical types.</p>
2955
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002956<h5>Semantics:</h5>
2957<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +00002958 This instruction always performs an unsigned division to get the
2959 remainder.</p>
2960
Chris Lattner9aba1e22008-01-28 00:36:27 +00002961<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +00002962 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2963
Chris Lattner9aba1e22008-01-28 00:36:27 +00002964<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002965
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002966<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002967<pre>
2968 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002969</pre>
2970
2971</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002972
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002973<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +00002974<div class="doc_subsubsection">
2975 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2976</div>
2977
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002978<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +00002979
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002980<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00002981<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +00002982 &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 +00002983</pre>
Chris Lattner6704c212008-05-20 20:48:21 +00002984
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002985<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00002986<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
2987 division of its two operands. This instruction can also take
2988 <a href="#t_vector">vector</a> versions of the values in which case the
2989 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +00002990
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002991<h5>Arguments:</h5>
2992<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00002993 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2994 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00002995
Dan Gohmanf17a25c2007-07-18 16:29:46 +00002996<h5>Semantics:</h5>
2997<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +00002998 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2999 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3000 a value. For more information about the difference,
3001 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3002 Math Forum</a>. For a table of how this is implemented in various languages,
3003 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3004 Wikipedia: modulo operation</a>.</p>
3005
Chris Lattner9aba1e22008-01-28 00:36:27 +00003006<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +00003007 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3008
Chris Lattner9aba1e22008-01-28 00:36:27 +00003009<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +00003010 Overflow also leads to undefined behavior; this is a rare case, but can
3011 occur, for example, by taking the remainder of a 32-bit division of
3012 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3013 lets srem be implemented using instructions that return both the result of
3014 the division and the remainder.)</p>
3015
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003016<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003017<pre>
3018 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003019</pre>
3020
3021</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003022
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003023<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +00003024<div class="doc_subsubsection">
3025 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3026
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003027<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +00003028
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003029<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003030<pre>
3031 &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 +00003032</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003033
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003034<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003035<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3036 its two operands.</p>
3037
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003038<h5>Arguments:</h5>
3039<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00003040 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3041 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00003042
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003043<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003044<p>This instruction returns the <i>remainder</i> of a division. The remainder
3045 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00003046
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003047<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00003048<pre>
3049 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003050</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003051
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003052</div>
3053
3054<!-- ======================================================================= -->
3055<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3056Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003057
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003058<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003059
3060<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3061 program. They are generally very efficient instructions and can commonly be
3062 strength reduced from other instructions. They require two operands of the
3063 same type, execute an operation on them, and produce a single value. The
3064 resulting value is the same type as its operands.</p>
3065
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003066</div>
3067
3068<!-- _______________________________________________________________________ -->
3069<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3070Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003071
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003072<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003073
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003074<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003075<pre>
3076 &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 +00003077</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +00003078
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003079<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003080<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3081 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +00003082
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003083<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003084<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3085 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3086 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +00003087
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003088<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003089<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3090 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3091 is (statically or dynamically) negative or equal to or larger than the number
3092 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3093 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3094 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +00003095
Bill Wendlingf85859d2009-07-20 02:29:24 +00003096<h5>Example:</h5>
3097<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003098 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3099 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3100 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +00003101 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +00003102 &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 +00003103</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003104
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003105</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003106
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003107<!-- _______________________________________________________________________ -->
3108<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3109Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003110
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003111<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003112
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003113<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003114<pre>
3115 &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 +00003116</pre>
3117
3118<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003119<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3120 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003121
3122<h5>Arguments:</h5>
3123<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +00003124 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3125 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003126
3127<h5>Semantics:</h5>
3128<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +00003129 significant bits of the result will be filled with zero bits after the shift.
3130 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3131 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3132 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3133 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003134
3135<h5>Example:</h5>
3136<pre>
3137 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3138 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3139 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3140 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +00003141 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +00003142 &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 +00003143</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003144
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003145</div>
3146
3147<!-- _______________________________________________________________________ -->
3148<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3149Instruction</a> </div>
3150<div class="doc_text">
3151
3152<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003153<pre>
3154 &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 +00003155</pre>
3156
3157<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003158<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3159 operand shifted to the right a specified number of bits with sign
3160 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003161
3162<h5>Arguments:</h5>
3163<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +00003164 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3165 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003166
3167<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003168<p>This instruction always performs an arithmetic shift right operation, The
3169 most significant bits of the result will be filled with the sign bit
3170 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3171 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3172 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3173 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003174
3175<h5>Example:</h5>
3176<pre>
3177 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3178 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3179 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3180 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +00003181 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +00003182 &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 +00003183</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003184
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003185</div>
3186
3187<!-- _______________________________________________________________________ -->
3188<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3189Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +00003190
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003191<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +00003192
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003193<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00003194<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +00003195 &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 +00003196</pre>
Chris Lattner6704c212008-05-20 20:48:21 +00003197
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003198<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003199<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3200 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00003201
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003202<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00003203<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00003204 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3205 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00003206
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003207<h5>Semantics:</h5>
3208<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003209
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003210<table border="1" cellspacing="0" cellpadding="4">
3211 <tbody>
3212 <tr>
3213 <td>In0</td>
3214 <td>In1</td>
3215 <td>Out</td>
3216 </tr>
3217 <tr>
3218 <td>0</td>
3219 <td>0</td>
3220 <td>0</td>
3221 </tr>
3222 <tr>
3223 <td>0</td>
3224 <td>1</td>
3225 <td>0</td>
3226 </tr>
3227 <tr>
3228 <td>1</td>
3229 <td>0</td>
3230 <td>0</td>
3231 </tr>
3232 <tr>
3233 <td>1</td>
3234 <td>1</td>
3235 <td>1</td>
3236 </tr>
3237 </tbody>
3238</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003239
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003240<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00003241<pre>
3242 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003243 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3244 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3245</pre>
3246</div>
3247<!-- _______________________________________________________________________ -->
3248<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +00003249
Bill Wendlingf85859d2009-07-20 02:29:24 +00003250<div class="doc_text">
3251
3252<h5>Syntax:</h5>
3253<pre>
3254 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3255</pre>
3256
3257<h5>Overview:</h5>
3258<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3259 two operands.</p>
3260
3261<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00003262<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00003263 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3264 values. Both arguments must have identical types.</p>
3265
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003266<h5>Semantics:</h5>
3267<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003268
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003269<table border="1" cellspacing="0" cellpadding="4">
3270 <tbody>
3271 <tr>
3272 <td>In0</td>
3273 <td>In1</td>
3274 <td>Out</td>
3275 </tr>
3276 <tr>
3277 <td>0</td>
3278 <td>0</td>
3279 <td>0</td>
3280 </tr>
3281 <tr>
3282 <td>0</td>
3283 <td>1</td>
3284 <td>1</td>
3285 </tr>
3286 <tr>
3287 <td>1</td>
3288 <td>0</td>
3289 <td>1</td>
3290 </tr>
3291 <tr>
3292 <td>1</td>
3293 <td>1</td>
3294 <td>1</td>
3295 </tr>
3296 </tbody>
3297</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003298
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003299<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003300<pre>
3301 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003302 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3303 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3304</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003305
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003306</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003307
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003308<!-- _______________________________________________________________________ -->
3309<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3310Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003311
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003312<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003313
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003314<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003315<pre>
3316 &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 +00003317</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003318
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003319<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003320<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3321 its two operands. The <tt>xor</tt> is used to implement the "one's
3322 complement" operation, which is the "~" operator in C.</p>
3323
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003324<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00003325<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +00003326 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3327 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00003328
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003329<h5>Semantics:</h5>
3330<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003331
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003332<table border="1" cellspacing="0" cellpadding="4">
3333 <tbody>
3334 <tr>
3335 <td>In0</td>
3336 <td>In1</td>
3337 <td>Out</td>
3338 </tr>
3339 <tr>
3340 <td>0</td>
3341 <td>0</td>
3342 <td>0</td>
3343 </tr>
3344 <tr>
3345 <td>0</td>
3346 <td>1</td>
3347 <td>1</td>
3348 </tr>
3349 <tr>
3350 <td>1</td>
3351 <td>0</td>
3352 <td>1</td>
3353 </tr>
3354 <tr>
3355 <td>1</td>
3356 <td>1</td>
3357 <td>0</td>
3358 </tr>
3359 </tbody>
3360</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003361
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003362<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003363<pre>
3364 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003365 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3366 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3367 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3368</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003369
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003370</div>
3371
3372<!-- ======================================================================= -->
3373<div class="doc_subsection">
3374 <a name="vectorops">Vector Operations</a>
3375</div>
3376
3377<div class="doc_text">
3378
3379<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +00003380 target-independent manner. These instructions cover the element-access and
3381 vector-specific operations needed to process vectors effectively. While LLVM
3382 does directly support these vector operations, many sophisticated algorithms
3383 will want to use target-specific intrinsics to take full advantage of a
3384 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003385
3386</div>
3387
3388<!-- _______________________________________________________________________ -->
3389<div class="doc_subsubsection">
3390 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3391</div>
3392
3393<div class="doc_text">
3394
3395<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003396<pre>
3397 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3398</pre>
3399
3400<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003401<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3402 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003403
3404
3405<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003406<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3407 of <a href="#t_vector">vector</a> type. The second operand is an index
3408 indicating the position from which to extract the element. The index may be
3409 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003410
3411<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003412<p>The result is a scalar of the same type as the element type of
3413 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3414 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3415 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003416
3417<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003418<pre>
3419 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3420</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003421
Bill Wendlingf85859d2009-07-20 02:29:24 +00003422</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003423
3424<!-- _______________________________________________________________________ -->
3425<div class="doc_subsubsection">
3426 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3427</div>
3428
3429<div class="doc_text">
3430
3431<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003432<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +00003433 &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 +00003434</pre>
3435
3436<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003437<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3438 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003439
3440<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003441<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3442 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3443 whose type must equal the element type of the first operand. The third
3444 operand is an index indicating the position at which to insert the value.
3445 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003446
3447<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003448<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3449 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3450 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3451 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003452
3453<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003454<pre>
3455 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3456</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003457
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003458</div>
3459
3460<!-- _______________________________________________________________________ -->
3461<div class="doc_subsubsection">
3462 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3463</div>
3464
3465<div class="doc_text">
3466
3467<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003468<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +00003469 &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 +00003470</pre>
3471
3472<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003473<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3474 from two input vectors, returning a vector with the same element type as the
3475 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003476
3477<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003478<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3479 with types that match each other. The third argument is a shuffle mask whose
3480 element type is always 'i32'. The result of the instruction is a vector
3481 whose length is the same as the shuffle mask and whose element type is the
3482 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003483
Bill Wendlingf85859d2009-07-20 02:29:24 +00003484<p>The shuffle mask operand is required to be a constant vector with either
3485 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003486
3487<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003488<p>The elements of the two input vectors are numbered from left to right across
3489 both of the vectors. The shuffle mask operand specifies, for each element of
3490 the result vector, which element of the two input vectors the result element
3491 gets. The element selector may be undef (meaning "don't care") and the
3492 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003493
3494<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003495<pre>
3496 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3497 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3498 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3499 &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 +00003500 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3501 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3502 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3503 &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 +00003504</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003505
Bill Wendlingf85859d2009-07-20 02:29:24 +00003506</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003507
3508<!-- ======================================================================= -->
3509<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +00003510 <a name="aggregateops">Aggregate Operations</a>
3511</div>
3512
3513<div class="doc_text">
3514
Bill Wendlingf85859d2009-07-20 02:29:24 +00003515<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003516
3517</div>
3518
3519<!-- _______________________________________________________________________ -->
3520<div class="doc_subsubsection">
3521 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3522</div>
3523
3524<div class="doc_text">
3525
3526<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003527<pre>
3528 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3529</pre>
3530
3531<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003532<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3533 or array element from an aggregate value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003534
3535<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003536<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3537 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3538 operands are constant indices to specify which value to extract in a similar
3539 manner as indices in a
3540 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003541
3542<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003543<p>The result is the value at the position in the aggregate specified by the
3544 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003545
3546<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003547<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +00003548 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003549</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003550
Bill Wendlingf85859d2009-07-20 02:29:24 +00003551</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003552
3553<!-- _______________________________________________________________________ -->
3554<div class="doc_subsubsection">
3555 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3556</div>
3557
3558<div class="doc_text">
3559
3560<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003561<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +00003562 &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 +00003563</pre>
3564
3565<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003566<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3567 array element in an aggregate.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003568
3569
3570<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003571<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3572 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3573 second operand is a first-class value to insert. The following operands are
3574 constant indices indicating the position at which to insert the value in a
3575 similar manner as indices in a
3576 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3577 value to insert must have the same type as the value identified by the
3578 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003579
3580<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003581<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3582 that of <tt>val</tt> except that the value at the position specified by the
3583 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003584
3585<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003586<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +00003587 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +00003588</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003589
Dan Gohman74d6faf2008-05-12 23:51:09 +00003590</div>
3591
3592
3593<!-- ======================================================================= -->
3594<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003595 <a name="memoryops">Memory Access and Addressing Operations</a>
3596</div>
3597
3598<div class="doc_text">
3599
Bill Wendlingf85859d2009-07-20 02:29:24 +00003600<p>A key design point of an SSA-based representation is how it represents
3601 memory. In LLVM, no memory locations are in SSA form, which makes things
3602 very simple. This section describes how to read, write, allocate, and free
3603 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003604
3605</div>
3606
3607<!-- _______________________________________________________________________ -->
3608<div class="doc_subsubsection">
3609 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3610</div>
3611
3612<div class="doc_text">
3613
3614<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003615<pre>
3616 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3617</pre>
3618
3619<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003620<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3621 returns a pointer to it. The object is always allocated in the generic
3622 address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003623
3624<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003625<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlingf85859d2009-07-20 02:29:24 +00003626 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3627 system and returns a pointer of the appropriate type to the program. If
3628 "NumElements" is specified, it is the number of elements allocated, otherwise
3629 "NumElements" is defaulted to be one. If a constant alignment is specified,
3630 the value result of the allocation is guaranteed to be aligned to at least
3631 that boundary. If not specified, or if zero, the target can choose to align
3632 the allocation on any convenient boundary compatible with the type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003633
3634<p>'<tt>type</tt>' must be a sized type.</p>
3635
3636<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003637<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3638 pointer is returned. The result of a zero byte allocation is undefined. The
3639 result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003640
3641<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003642<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +00003643 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003644
3645 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3646 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3647 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3648 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3649 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3650</pre>
Dan Gohman60967192009-01-12 23:12:39 +00003651
Bill Wendlingf85859d2009-07-20 02:29:24 +00003652<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohman60967192009-01-12 23:12:39 +00003653
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003654</div>
3655
3656<!-- _______________________________________________________________________ -->
3657<div class="doc_subsubsection">
3658 <a name="i_free">'<tt>free</tt>' Instruction</a>
3659</div>
3660
3661<div class="doc_text">
3662
3663<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003664<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +00003665 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003666</pre>
3667
3668<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003669<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3670 to be reallocated in the future.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003671
3672<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003673<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3674 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003675
3676<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003677<p>Access to the memory pointed to by the pointer is no longer defined after
3678 this instruction executes. If the pointer is null, the operation is a
3679 noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003680
3681<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003682<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +00003683 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003684 free [4 x i8]* %array
3685</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003686
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003687</div>
3688
3689<!-- _______________________________________________________________________ -->
3690<div class="doc_subsubsection">
3691 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3692</div>
3693
3694<div class="doc_text">
3695
3696<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003697<pre>
3698 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3699</pre>
3700
3701<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003702<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +00003703 currently executing function, to be automatically released when this function
3704 returns to its caller. The object is always allocated in the generic address
3705 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003706
3707<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003708<p>The '<tt>alloca</tt>' instruction
3709 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3710 runtime stack, returning a pointer of the appropriate type to the program.
3711 If "NumElements" is specified, it is the number of elements allocated,
3712 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3713 specified, the value result of the allocation is guaranteed to be aligned to
3714 at least that boundary. If not specified, or if zero, the target can choose
3715 to align the allocation on any convenient boundary compatible with the
3716 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003717
3718<p>'<tt>type</tt>' may be any sized type.</p>
3719
3720<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +00003721<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +00003722 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3723 memory is automatically released when the function returns. The
3724 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3725 variables that must have an address available. When the function returns
3726 (either with the <tt><a href="#i_ret">ret</a></tt>
3727 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3728 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003729
3730<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003731<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +00003732 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3733 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3734 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3735 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003736</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003737
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003738</div>
3739
3740<!-- _______________________________________________________________________ -->
3741<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3742Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003743
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003744<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003745
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003746<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003747<pre>
3748 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3749 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3750</pre>
3751
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003752<h5>Overview:</h5>
3753<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003754
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003755<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003756<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3757 from which to load. The pointer must point to
3758 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3759 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3760 number or order of execution of this <tt>load</tt> with other
3761 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3762 instructions. </p>
3763
3764<p>The optional constant "align" argument specifies the alignment of the
3765 operation (that is, the alignment of the memory address). A value of 0 or an
3766 omitted "align" argument means that the operation has the preferential
3767 alignment for the target. It is the responsibility of the code emitter to
3768 ensure that the alignment information is correct. Overestimating the
3769 alignment results in an undefined behavior. Underestimating the alignment may
3770 produce less efficient code. An alignment of 1 is always safe.</p>
3771
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003772<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003773<p>The location of memory pointed to is loaded. If the value being loaded is of
3774 scalar type then the number of bytes read does not exceed the minimum number
3775 of bytes needed to hold all bits of the type. For example, loading an
3776 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3777 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3778 is undefined if the value was not originally written using a store of the
3779 same type.</p>
3780
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003781<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003782<pre>
3783 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3784 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003785 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3786</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003787
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003788</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003789
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003790<!-- _______________________________________________________________________ -->
3791<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3792Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003793
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003794<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003795
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003796<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003797<pre>
3798 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 +00003799 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3800</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003801
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003802<h5>Overview:</h5>
3803<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003804
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003805<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003806<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
3807 and an address at which to store it. The type of the
3808 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
3809 the <a href="#t_firstclass">first class</a> type of the
3810 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
3811 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
3812 or order of execution of this <tt>store</tt> with other
3813 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3814 instructions.</p>
3815
3816<p>The optional constant "align" argument specifies the alignment of the
3817 operation (that is, the alignment of the memory address). A value of 0 or an
3818 omitted "align" argument means that the operation has the preferential
3819 alignment for the target. It is the responsibility of the code emitter to
3820 ensure that the alignment information is correct. Overestimating the
3821 alignment results in an undefined behavior. Underestimating the alignment may
3822 produce less efficient code. An alignment of 1 is always safe.</p>
3823
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003824<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003825<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
3826 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
3827 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
3828 does not exceed the minimum number of bytes needed to hold all bits of the
3829 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
3830 writing a value of a type like <tt>i20</tt> with a size that is not an
3831 integral number of bytes, it is unspecified what happens to the extra bits
3832 that do not belong to the type, but they will typically be overwritten.</p>
3833
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003834<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003835<pre>
3836 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +00003837 store i32 3, i32* %ptr <i>; yields {void}</i>
3838 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003839</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003840
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003841</div>
3842
3843<!-- _______________________________________________________________________ -->
3844<div class="doc_subsubsection">
3845 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3846</div>
3847
3848<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003849
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003850<h5>Syntax:</h5>
3851<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +00003852 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003853</pre>
3854
3855<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003856<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
3857 subelement of an aggregate data structure. It performs address calculation
3858 only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003859
3860<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +00003861<p>The first argument is always a pointer, and forms the basis of the
Bill Wendlingf85859d2009-07-20 02:29:24 +00003862 calculation. The remaining arguments are indices, that indicate which of the
3863 elements of the aggregate object are indexed. The interpretation of each
3864 index is dependent on the type being indexed into. The first index always
3865 indexes the pointer value given as the first argument, the second index
3866 indexes a value of the type pointed to (not necessarily the value directly
3867 pointed to, since the first index can be non-zero), etc. The first type
3868 indexed into must be a pointer value, subsequent types can be arrays, vectors
3869 and structs. Note that subsequent types being indexed into can never be
3870 pointers, since that would require loading the pointer before continuing
3871 calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +00003872
3873<p>The type of each index argument depends on the type it is indexing into.
Bill Wendlingf85859d2009-07-20 02:29:24 +00003874 When indexing into a (packed) structure, only <tt>i32</tt> integer
3875 <b>constants</b> are allowed. When indexing into an array, pointer or
3876 vector, integers of any width are allowed (also non-constants).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003877
Bill Wendlingf85859d2009-07-20 02:29:24 +00003878<p>For example, let's consider a C code fragment and how it gets compiled to
3879 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003880
3881<div class="doc_code">
3882<pre>
3883struct RT {
3884 char A;
3885 int B[10][20];
3886 char C;
3887};
3888struct ST {
3889 int X;
3890 double Y;
3891 struct RT Z;
3892};
3893
3894int *foo(struct ST *s) {
3895 return &amp;s[1].Z.B[5][13];
3896}
3897</pre>
3898</div>
3899
3900<p>The LLVM code generated by the GCC frontend is:</p>
3901
3902<div class="doc_code">
3903<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +00003904%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3905%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003906
3907define i32* %foo(%ST* %s) {
3908entry:
3909 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3910 ret i32* %reg
3911}
3912</pre>
3913</div>
3914
3915<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003916<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +00003917 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3918 }</tt>' type, a structure. The second index indexes into the third element
3919 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3920 i8 }</tt>' type, another structure. The third index indexes into the second
3921 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3922 array. The two dimensions of the array are subscripted into, yielding an
3923 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
3924 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003925
Bill Wendlingf85859d2009-07-20 02:29:24 +00003926<p>Note that it is perfectly legal to index partially through a structure,
3927 returning a pointer to an inner element. Because of this, the LLVM code for
3928 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003929
3930<pre>
3931 define i32* %foo(%ST* %s) {
3932 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3933 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3934 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3935 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3936 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3937 ret i32* %t5
3938 }
3939</pre>
3940
Bill Wendlingf85859d2009-07-20 02:29:24 +00003941<p>The getelementptr instruction is often confusing. For some more insight into
3942 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003943
3944<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003945<pre>
3946 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +00003947 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3948 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +00003949 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman32a080e2008-10-13 13:44:15 +00003950 <i>; yields i8*:eptr</i>
3951 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +00003952 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +00003953 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003954</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003955
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003956</div>
3957
3958<!-- ======================================================================= -->
3959<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3960</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003961
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003962<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00003963
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003964<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +00003965 which all take a single operand and a type. They perform various bit
3966 conversions on the operand.</p>
3967
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003968</div>
3969
3970<!-- _______________________________________________________________________ -->
3971<div class="doc_subsubsection">
3972 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3973</div>
3974<div class="doc_text">
3975
3976<h5>Syntax:</h5>
3977<pre>
3978 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3979</pre>
3980
3981<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003982<p>The '<tt>trunc</tt>' instruction truncates its operand to the
3983 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003984
3985<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003986<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3987 be an <a href="#t_integer">integer</a> type, and a type that specifies the
3988 size and type of the result, which must be
3989 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
3990 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
3991 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003992
3993<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00003994<p>The '<tt>trunc</tt>' instruction truncates the high order bits
3995 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
3996 source size must be larger than the destination size, <tt>trunc</tt> cannot
3997 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00003998
3999<h5>Example:</h5>
4000<pre>
4001 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4002 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4003 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
4004</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004005
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004006</div>
4007
4008<!-- _______________________________________________________________________ -->
4009<div class="doc_subsubsection">
4010 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4011</div>
4012<div class="doc_text">
4013
4014<h5>Syntax:</h5>
4015<pre>
4016 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4017</pre>
4018
4019<h5>Overview:</h5>
4020<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +00004021 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004022
4023
4024<h5>Arguments:</h5>
4025<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Bill Wendlingf85859d2009-07-20 02:29:24 +00004026 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4027 also be of <a href="#t_integer">integer</a> type. The bit size of the
4028 <tt>value</tt> must be smaller than the bit size of the destination type,
4029 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004030
4031<h5>Semantics:</h5>
4032<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlingf85859d2009-07-20 02:29:24 +00004033 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004034
4035<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4036
4037<h5>Example:</h5>
4038<pre>
4039 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4040 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4041</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004042
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004043</div>
4044
4045<!-- _______________________________________________________________________ -->
4046<div class="doc_subsubsection">
4047 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4048</div>
4049<div class="doc_text">
4050
4051<h5>Syntax:</h5>
4052<pre>
4053 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4054</pre>
4055
4056<h5>Overview:</h5>
4057<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4058
4059<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004060<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4061 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4062 also be of <a href="#t_integer">integer</a> type. The bit size of the
4063 <tt>value</tt> must be smaller than the bit size of the destination type,
4064 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004065
4066<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004067<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4068 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4069 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004070
4071<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4072
4073<h5>Example:</h5>
4074<pre>
4075 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4076 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4077</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004078
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004079</div>
4080
4081<!-- _______________________________________________________________________ -->
4082<div class="doc_subsubsection">
4083 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4084</div>
4085
4086<div class="doc_text">
4087
4088<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004089<pre>
4090 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4091</pre>
4092
4093<h5>Overview:</h5>
4094<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +00004095 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004096
4097<h5>Arguments:</h5>
4098<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +00004099 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4100 to cast it to. The size of <tt>value</tt> must be larger than the size of
4101 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4102 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004103
4104<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004105<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4106 <a href="#t_floating">floating point</a> type to a smaller
4107 <a href="#t_floating">floating point</a> type. If the value cannot fit
4108 within the destination type, <tt>ty2</tt>, then the results are
4109 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004110
4111<h5>Example:</h5>
4112<pre>
4113 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4114 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4115</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004116
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004117</div>
4118
4119<!-- _______________________________________________________________________ -->
4120<div class="doc_subsubsection">
4121 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4122</div>
4123<div class="doc_text">
4124
4125<h5>Syntax:</h5>
4126<pre>
4127 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4128</pre>
4129
4130<h5>Overview:</h5>
4131<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlingf85859d2009-07-20 02:29:24 +00004132 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004133
4134<h5>Arguments:</h5>
4135<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +00004136 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4137 a <a href="#t_floating">floating point</a> type to cast it to. The source
4138 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004139
4140<h5>Semantics:</h5>
4141<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +00004142 <a href="#t_floating">floating point</a> type to a larger
4143 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4144 used to make a <i>no-op cast</i> because it always changes bits. Use
4145 <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004146
4147<h5>Example:</h5>
4148<pre>
4149 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4150 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4151</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004152
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004153</div>
4154
4155<!-- _______________________________________________________________________ -->
4156<div class="doc_subsubsection">
4157 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4158</div>
4159<div class="doc_text">
4160
4161<h5>Syntax:</h5>
4162<pre>
Reid Spencere6adee82007-07-31 14:40:14 +00004163 &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 +00004164</pre>
4165
4166<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +00004167<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +00004168 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004169
4170<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004171<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4172 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4173 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4174 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4175 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004176
4177<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004178<p>The '<tt>fptoui</tt>' instruction converts its
4179 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4180 towards zero) unsigned integer value. If the value cannot fit
4181 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004182
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004183<h5>Example:</h5>
4184<pre>
Reid Spencere6adee82007-07-31 14:40:14 +00004185 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +00004186 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +00004187 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004188</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004189
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004190</div>
4191
4192<!-- _______________________________________________________________________ -->
4193<div class="doc_subsubsection">
4194 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4195</div>
4196<div class="doc_text">
4197
4198<h5>Syntax:</h5>
4199<pre>
4200 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4201</pre>
4202
4203<h5>Overview:</h5>
4204<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +00004205 <a href="#t_floating">floating point</a> <tt>value</tt> to
4206 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004207
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004208<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004209<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4210 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4211 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4212 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4213 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004214
4215<h5>Semantics:</h5>
4216<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +00004217 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4218 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4219 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004220
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004221<h5>Example:</h5>
4222<pre>
4223 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +00004224 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004225 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4226</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004227
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004228</div>
4229
4230<!-- _______________________________________________________________________ -->
4231<div class="doc_subsubsection">
4232 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4233</div>
4234<div class="doc_text">
4235
4236<h5>Syntax:</h5>
4237<pre>
4238 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4239</pre>
4240
4241<h5>Overview:</h5>
4242<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +00004243 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004244
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004245<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +00004246<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingf85859d2009-07-20 02:29:24 +00004247 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4248 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4249 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4250 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004251
4252<h5>Semantics:</h5>
4253<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +00004254 integer quantity and converts it to the corresponding floating point
4255 value. If the value cannot fit in the floating point value, the results are
4256 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004257
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004258<h5>Example:</h5>
4259<pre>
4260 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +00004261 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004262</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004263
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004264</div>
4265
4266<!-- _______________________________________________________________________ -->
4267<div class="doc_subsubsection">
4268 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4269</div>
4270<div class="doc_text">
4271
4272<h5>Syntax:</h5>
4273<pre>
4274 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4275</pre>
4276
4277<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004278<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4279 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004280
4281<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +00004282<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingf85859d2009-07-20 02:29:24 +00004283 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4284 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4285 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4286 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004287
4288<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004289<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4290 quantity and converts it to the corresponding floating point value. If the
4291 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004292
4293<h5>Example:</h5>
4294<pre>
4295 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +00004296 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004297</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004298
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004299</div>
4300
4301<!-- _______________________________________________________________________ -->
4302<div class="doc_subsubsection">
4303 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4304</div>
4305<div class="doc_text">
4306
4307<h5>Syntax:</h5>
4308<pre>
4309 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4310</pre>
4311
4312<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004313<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4314 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004315
4316<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004317<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4318 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4319 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004320
4321<h5>Semantics:</h5>
4322<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +00004323 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4324 truncating or zero extending that value to the size of the integer type. If
4325 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4326 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4327 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4328 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004329
4330<h5>Example:</h5>
4331<pre>
4332 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4333 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4334</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004335
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004336</div>
4337
4338<!-- _______________________________________________________________________ -->
4339<div class="doc_subsubsection">
4340 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4341</div>
4342<div class="doc_text">
4343
4344<h5>Syntax:</h5>
4345<pre>
4346 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4347</pre>
4348
4349<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004350<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4351 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004352
4353<h5>Arguments:</h5>
4354<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004355 value to cast, and a type to cast it to, which must be a
4356 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004357
4358<h5>Semantics:</h5>
4359<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +00004360 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4361 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4362 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4363 than the size of a pointer then a zero extension is done. If they are the
4364 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004365
4366<h5>Example:</h5>
4367<pre>
4368 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4369 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4370 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4371</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004372
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004373</div>
4374
4375<!-- _______________________________________________________________________ -->
4376<div class="doc_subsubsection">
4377 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4378</div>
4379<div class="doc_text">
4380
4381<h5>Syntax:</h5>
4382<pre>
4383 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4384</pre>
4385
4386<h5>Overview:</h5>
4387<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +00004388 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004389
4390<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004391<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4392 non-aggregate first class value, and a type to cast it to, which must also be
4393 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4394 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4395 identical. If the source type is a pointer, the destination type must also be
4396 a pointer. This instruction supports bitwise conversion of vectors to
4397 integers and to vectors of other types (as long as they have the same
4398 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004399
4400<h5>Semantics:</h5>
4401<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +00004402 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4403 this conversion. The conversion is done as if the <tt>value</tt> had been
4404 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4405 be converted to other pointer types with this instruction. To convert
4406 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4407 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004408
4409<h5>Example:</h5>
4410<pre>
4411 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4412 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +00004413 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004414</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004415
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004416</div>
4417
4418<!-- ======================================================================= -->
4419<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004420
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004421<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00004422
4423<p>The instructions in this category are the "miscellaneous" instructions, which
4424 defy better classification.</p>
4425
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004426</div>
4427
4428<!-- _______________________________________________________________________ -->
4429<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4430</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004431
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004432<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00004433
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004434<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004435<pre>
4436 &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 +00004437</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004438
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004439<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004440<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4441 boolean values based on comparison of its two integer, integer vector, or
4442 pointer operands.</p>
4443
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004444<h5>Arguments:</h5>
4445<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +00004446 the condition code indicating the kind of comparison to perform. It is not a
4447 value, just a keyword. The possible condition code are:</p>
4448
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004449<ol>
4450 <li><tt>eq</tt>: equal</li>
4451 <li><tt>ne</tt>: not equal </li>
4452 <li><tt>ugt</tt>: unsigned greater than</li>
4453 <li><tt>uge</tt>: unsigned greater or equal</li>
4454 <li><tt>ult</tt>: unsigned less than</li>
4455 <li><tt>ule</tt>: unsigned less or equal</li>
4456 <li><tt>sgt</tt>: signed greater than</li>
4457 <li><tt>sge</tt>: signed greater or equal</li>
4458 <li><tt>slt</tt>: signed less than</li>
4459 <li><tt>sle</tt>: signed less or equal</li>
4460</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004461
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004462<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +00004463 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4464 typed. They must also be identical types.</p>
4465
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004466<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004467<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4468 condition code given as <tt>cond</tt>. The comparison performed always yields
4469 either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt>
4470 result, as follows:</p>
4471
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004472<ol>
4473 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +00004474 <tt>false</tt> otherwise. No sign interpretation is necessary or
4475 performed.</li>
4476
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004477 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +00004478 <tt>false</tt> otherwise. No sign interpretation is necessary or
4479 performed.</li>
4480
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004481 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +00004482 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4483
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004484 <li><tt>uge</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 or equal
4486 to <tt>op2</tt>.</li>
4487
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004488 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +00004489 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4490
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004491 <li><tt>ule</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 or equal to <tt>op2</tt>.</li>
4493
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004494 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +00004495 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4496
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004497 <li><tt>sge</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 or equal
4499 to <tt>op2</tt>.</li>
4500
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004501 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +00004502 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4503
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004504 <li><tt>sle</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 or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004506</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004507
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004508<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +00004509 values are compared as if they were integers.</p>
4510
4511<p>If the operands are integer vectors, then they are compared element by
4512 element. The result is an <tt>i1</tt> vector with the same number of elements
4513 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004514
4515<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004516<pre>
4517 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004518 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4519 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4520 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4521 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4522 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4523</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +00004524
4525<p>Note that the code generator does not yet support vector types with
4526 the <tt>icmp</tt> instruction.</p>
4527
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004528</div>
4529
4530<!-- _______________________________________________________________________ -->
4531<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4532</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004533
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004534<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00004535
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004536<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004537<pre>
4538 &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 +00004539</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004540
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004541<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004542<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4543 values based on comparison of its operands.</p>
4544
4545<p>If the operands are floating point scalars, then the result type is a boolean
4546(<a href="#t_primitive"><tt>i1</tt></a>).</p>
4547
4548<p>If the operands are floating point vectors, then the result type is a vector
4549 of boolean with the same number of elements as the operands being
4550 compared.</p>
4551
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004552<h5>Arguments:</h5>
4553<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +00004554 the condition code indicating the kind of comparison to perform. It is not a
4555 value, just a keyword. The possible condition code are:</p>
4556
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004557<ol>
4558 <li><tt>false</tt>: no comparison, always returns false</li>
4559 <li><tt>oeq</tt>: ordered and equal</li>
4560 <li><tt>ogt</tt>: ordered and greater than </li>
4561 <li><tt>oge</tt>: ordered and greater than or equal</li>
4562 <li><tt>olt</tt>: ordered and less than </li>
4563 <li><tt>ole</tt>: ordered and less than or equal</li>
4564 <li><tt>one</tt>: ordered and not equal</li>
4565 <li><tt>ord</tt>: ordered (no nans)</li>
4566 <li><tt>ueq</tt>: unordered or equal</li>
4567 <li><tt>ugt</tt>: unordered or greater than </li>
4568 <li><tt>uge</tt>: unordered or greater than or equal</li>
4569 <li><tt>ult</tt>: unordered or less than </li>
4570 <li><tt>ule</tt>: unordered or less than or equal</li>
4571 <li><tt>une</tt>: unordered or not equal</li>
4572 <li><tt>uno</tt>: unordered (either nans)</li>
4573 <li><tt>true</tt>: no comparison, always returns true</li>
4574</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004575
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004576<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +00004577 <i>unordered</i> means that either operand may be a QNAN.</p>
4578
4579<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4580 a <a href="#t_floating">floating point</a> type or
4581 a <a href="#t_vector">vector</a> of floating point type. They must have
4582 identical types.</p>
4583
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004584<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +00004585<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004586 according to the condition code given as <tt>cond</tt>. If the operands are
4587 vectors, then the vectors are compared element by element. Each comparison
4588 performed always yields an <a href="#t_primitive">i1</a> result, as
4589 follows:</p>
4590
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004591<ol>
4592 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004593
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004594 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +00004595 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4596
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004597 <li><tt>ogt</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 greather than <tt>op2</tt>.</li>
4599
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004600 <li><tt>oge</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 greater than or equal to <tt>op2</tt>.</li>
4602
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004603 <li><tt>olt</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 less than <tt>op2</tt>.</li>
4605
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004606 <li><tt>ole</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 or equal to <tt>op2</tt>.</li>
4608
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004609 <li><tt>one</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 not equal to <tt>op2</tt>.</li>
4611
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004612 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004613
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004614 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +00004615 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4616
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004617 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +00004618 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4619
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004620 <li><tt>uge</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 or equal to <tt>op2</tt>.</li>
4622
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004623 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +00004624 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4625
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004626 <li><tt>ule</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 or equal to <tt>op2</tt>.</li>
4628
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004629 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +00004630 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4631
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004632 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004633
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004634 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4635</ol>
4636
4637<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004638<pre>
4639 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +00004640 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4641 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4642 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004643</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +00004644
4645<p>Note that the code generator does not yet support vector types with
4646 the <tt>fcmp</tt> instruction.</p>
4647
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004648</div>
4649
4650<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +00004651<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +00004652 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4653</div>
4654
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004655<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +00004656
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004657<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004658<pre>
4659 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4660</pre>
Chris Lattner6704c212008-05-20 20:48:21 +00004661
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004662<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004663<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4664 SSA graph representing the function.</p>
4665
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004666<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004667<p>The type of the incoming values is specified with the first type field. After
4668 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4669 one pair for each predecessor basic block of the current block. Only values
4670 of <a href="#t_firstclass">first class</a> type may be used as the value
4671 arguments to the PHI node. Only labels may be used as the label
4672 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00004673
Bill Wendlingf85859d2009-07-20 02:29:24 +00004674<p>There must be no non-phi instructions between the start of a basic block and
4675 the PHI instructions: i.e. PHI instructions must be first in a basic
4676 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00004677
Bill Wendlingf85859d2009-07-20 02:29:24 +00004678<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4679 occur on the edge from the corresponding predecessor block to the current
4680 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4681 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +00004682
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004683<h5>Semantics:</h5>
4684<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +00004685 specified by the pair corresponding to the predecessor basic block that
4686 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +00004687
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004688<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +00004689<pre>
4690Loop: ; Infinite loop that counts from 0 on up...
4691 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4692 %nextindvar = add i32 %indvar, 1
4693 br label %Loop
4694</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004695
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004696</div>
4697
4698<!-- _______________________________________________________________________ -->
4699<div class="doc_subsubsection">
4700 <a name="i_select">'<tt>select</tt>' Instruction</a>
4701</div>
4702
4703<div class="doc_text">
4704
4705<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004706<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +00004707 &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>
4708
Dan Gohman2672f3e2008-10-14 16:51:45 +00004709 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004710</pre>
4711
4712<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004713<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4714 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004715
4716
4717<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004718<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4719 values indicating the condition, and two values of the
4720 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4721 vectors and the condition is a scalar, then entire vectors are selected, not
4722 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004723
4724<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004725<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4726 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004727
Bill Wendlingf85859d2009-07-20 02:29:24 +00004728<p>If the condition is a vector of i1, then the value arguments must be vectors
4729 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004730
4731<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004732<pre>
4733 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4734</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +00004735
4736<p>Note that the code generator does not yet support conditions
4737 with vector type.</p>
4738
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004739</div>
4740
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004741<!-- _______________________________________________________________________ -->
4742<div class="doc_subsubsection">
4743 <a name="i_call">'<tt>call</tt>' Instruction</a>
4744</div>
4745
4746<div class="doc_text">
4747
4748<h5>Syntax:</h5>
4749<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +00004750 &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 +00004751</pre>
4752
4753<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004754<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4755
4756<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004757<p>This instruction requires several arguments:</p>
4758
4759<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004760 <li>The optional "tail" marker indicates whether the callee function accesses
4761 any allocas or varargs in the caller. If the "tail" marker is present,
4762 the function call is eligible for tail call optimization. Note that calls
4763 may be marked "tail" even if they do not occur before
4764 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelac2fc272008-10-06 18:50:38 +00004765
Bill Wendlingf85859d2009-07-20 02:29:24 +00004766 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4767 convention</a> the call should use. If none is specified, the call
4768 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +00004769
Bill Wendlingf85859d2009-07-20 02:29:24 +00004770 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4771 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4772 '<tt>inreg</tt>' attributes are valid here.</li>
4773
4774 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
4775 type of the return value. Functions that return no value are marked
4776 <tt><a href="#t_void">void</a></tt>.</li>
4777
4778 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
4779 being invoked. The argument types must match the types implied by this
4780 signature. This type can be omitted if the function is not varargs and if
4781 the function type does not return a pointer to a function.</li>
4782
4783 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4784 be invoked. In most cases, this is a direct function invocation, but
4785 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4786 to function value.</li>
4787
4788 <li>'<tt>function args</tt>': argument list whose types match the function
4789 signature argument types. All arguments must be of
4790 <a href="#t_firstclass">first class</a> type. If the function signature
4791 indicates the function accepts a variable number of arguments, the extra
4792 arguments can be specified.</li>
4793
4794 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
4795 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4796 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004797</ol>
4798
4799<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004800<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
4801 a specified function, with its incoming arguments bound to the specified
4802 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
4803 function, control flow continues with the instruction after the function
4804 call, and the return value of the function is bound to the result
4805 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004806
4807<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004808<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +00004809 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +00004810 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4811 %X = tail call i32 @foo() <i>; yields i32</i>
4812 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4813 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +00004814
4815 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +00004816 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +00004817 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4818 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +00004819 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +00004820 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004821</pre>
4822
4823</div>
4824
4825<!-- _______________________________________________________________________ -->
4826<div class="doc_subsubsection">
4827 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4828</div>
4829
4830<div class="doc_text">
4831
4832<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004833<pre>
4834 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4835</pre>
4836
4837<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004838<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +00004839 the "variable argument" area of a function call. It is used to implement the
4840 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004841
4842<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004843<p>This instruction takes a <tt>va_list*</tt> value and the type of the
4844 argument. It returns a value of the specified argument type and increments
4845 the <tt>va_list</tt> to point to the next argument. The actual type
4846 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004847
4848<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004849<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
4850 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
4851 to the next argument. For more information, see the variable argument
4852 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004853
4854<p>It is legal for this instruction to be called in a function which does not
Bill Wendlingf85859d2009-07-20 02:29:24 +00004855 take a variable number of arguments, for example, the <tt>vfprintf</tt>
4856 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004857
Bill Wendlingf85859d2009-07-20 02:29:24 +00004858<p><tt>va_arg</tt> is an LLVM instruction instead of
4859 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
4860 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004861
4862<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004863<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4864
Bill Wendlingf85859d2009-07-20 02:29:24 +00004865<p>Note that the code generator does not yet fully support va_arg on many
4866 targets. Also, it does not currently support va_arg with aggregate types on
4867 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +00004868
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004869</div>
4870
4871<!-- *********************************************************************** -->
4872<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4873<!-- *********************************************************************** -->
4874
4875<div class="doc_text">
4876
4877<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +00004878 well known names and semantics and are required to follow certain
4879 restrictions. Overall, these intrinsics represent an extension mechanism for
4880 the LLVM language that does not require changing all of the transformations
4881 in LLVM when adding to the language (or the bitcode reader/writer, the
4882 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004883
4884<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +00004885 prefix is reserved in LLVM for intrinsic names; thus, function names may not
4886 begin with this prefix. Intrinsic functions must always be external
4887 functions: you cannot define the body of intrinsic functions. Intrinsic
4888 functions may only be used in call or invoke instructions: it is illegal to
4889 take the address of an intrinsic function. Additionally, because intrinsic
4890 functions are part of the LLVM language, it is required if any are added that
4891 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004892
Bill Wendlingf85859d2009-07-20 02:29:24 +00004893<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
4894 family of functions that perform the same operation but on different data
4895 types. Because LLVM can represent over 8 million different integer types,
4896 overloading is used commonly to allow an intrinsic function to operate on any
4897 integer type. One or more of the argument types or the result type can be
4898 overloaded to accept any integer type. Argument types may also be defined as
4899 exactly matching a previous argument's type or the result type. This allows
4900 an intrinsic function which accepts multiple arguments, but needs all of them
4901 to be of the same type, to only be overloaded with respect to a single
4902 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004903
Bill Wendlingf85859d2009-07-20 02:29:24 +00004904<p>Overloaded intrinsics will have the names of its overloaded argument types
4905 encoded into its function name, each preceded by a period. Only those types
4906 which are overloaded result in a name suffix. Arguments whose type is matched
4907 against another type do not. For example, the <tt>llvm.ctpop</tt> function
4908 can take an integer of any width and returns an integer of exactly the same
4909 integer width. This leads to a family of functions such as
4910 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
4911 %val)</tt>. Only one type, the return type, is overloaded, and only one type
4912 suffix is required. Because the argument's type is matched against the return
4913 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004914
4915<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +00004916 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004917
4918</div>
4919
4920<!-- ======================================================================= -->
4921<div class="doc_subsection">
4922 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4923</div>
4924
4925<div class="doc_text">
4926
Bill Wendlingf85859d2009-07-20 02:29:24 +00004927<p>Variable argument support is defined in LLVM with
4928 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4929 intrinsic functions. These functions are related to the similarly named
4930 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004931
Bill Wendlingf85859d2009-07-20 02:29:24 +00004932<p>All of these functions operate on arguments that use a target-specific value
4933 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
4934 not define what this type is, so all transformations should be prepared to
4935 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004936
4937<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004938 instruction and the variable argument handling intrinsic functions are
4939 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004940
4941<div class="doc_code">
4942<pre>
4943define i32 @test(i32 %X, ...) {
4944 ; Initialize variable argument processing
4945 %ap = alloca i8*
4946 %ap2 = bitcast i8** %ap to i8*
4947 call void @llvm.va_start(i8* %ap2)
4948
4949 ; Read a single integer argument
4950 %tmp = va_arg i8** %ap, i32
4951
4952 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4953 %aq = alloca i8*
4954 %aq2 = bitcast i8** %aq to i8*
4955 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4956 call void @llvm.va_end(i8* %aq2)
4957
4958 ; Stop processing of arguments.
4959 call void @llvm.va_end(i8* %ap2)
4960 ret i32 %tmp
4961}
4962
4963declare void @llvm.va_start(i8*)
4964declare void @llvm.va_copy(i8*, i8*)
4965declare void @llvm.va_end(i8*)
4966</pre>
4967</div>
4968
4969</div>
4970
4971<!-- _______________________________________________________________________ -->
4972<div class="doc_subsubsection">
4973 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4974</div>
4975
4976
4977<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00004978
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004979<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004980<pre>
4981 declare void %llvm.va_start(i8* &lt;arglist&gt;)
4982</pre>
4983
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004984<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004985<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
4986 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004987
4988<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +00004989<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004990
4991<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +00004992<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00004993 macro available in C. In a target-dependent way, it initializes
4994 the <tt>va_list</tt> element to which the argument points, so that the next
4995 call to <tt>va_arg</tt> will produce the first variable argument passed to
4996 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
4997 need to know the last argument of the function as the compiler can figure
4998 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00004999
5000</div>
5001
5002<!-- _______________________________________________________________________ -->
5003<div class="doc_subsubsection">
5004 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5005</div>
5006
5007<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005008
Bill Wendlingf85859d2009-07-20 02:29:24 +00005009<h5>Syntax:</h5>
5010<pre>
5011 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5012</pre>
5013
5014<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005015<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +00005016 which has been initialized previously
5017 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5018 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005019
5020<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005021<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5022
5023<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005024<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005025 macro available in C. In a target-dependent way, it destroys
5026 the <tt>va_list</tt> element to which the argument points. Calls
5027 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5028 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5029 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005030
5031</div>
5032
5033<!-- _______________________________________________________________________ -->
5034<div class="doc_subsubsection">
5035 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5036</div>
5037
5038<div class="doc_text">
5039
5040<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005041<pre>
5042 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5043</pre>
5044
5045<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005046<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +00005047 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005048
5049<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005050<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlingf85859d2009-07-20 02:29:24 +00005051 The second argument is a pointer to a <tt>va_list</tt> element to copy
5052 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005053
5054<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005055<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005056 macro available in C. In a target-dependent way, it copies the
5057 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5058 element. This intrinsic is necessary because
5059 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5060 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005061
5062</div>
5063
5064<!-- ======================================================================= -->
5065<div class="doc_subsection">
5066 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5067</div>
5068
5069<div class="doc_text">
5070
Bill Wendlingf85859d2009-07-20 02:29:24 +00005071<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +00005072Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +00005073intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5074roots on the stack</a>, as well as garbage collector implementations that
5075require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5076barriers. Front-ends for type-safe garbage collected languages should generate
5077these intrinsics to make use of the LLVM garbage collectors. For more details,
5078see <a href="GarbageCollection.html">Accurate Garbage Collection with
5079LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +00005080
Bill Wendlingf85859d2009-07-20 02:29:24 +00005081<p>The garbage collection intrinsics only operate on objects in the generic
5082 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +00005083
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005084</div>
5085
5086<!-- _______________________________________________________________________ -->
5087<div class="doc_subsubsection">
5088 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5089</div>
5090
5091<div class="doc_text">
5092
5093<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005094<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +00005095 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005096</pre>
5097
5098<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005099<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlingf85859d2009-07-20 02:29:24 +00005100 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005101
5102<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005103<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +00005104 root pointer. The second pointer (which must be either a constant or a
5105 global value address) contains the meta-data to be associated with the
5106 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005107
5108<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +00005109<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlingf85859d2009-07-20 02:29:24 +00005110 location. At compile-time, the code generator generates information to allow
5111 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5112 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5113 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005114
5115</div>
5116
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005117<!-- _______________________________________________________________________ -->
5118<div class="doc_subsubsection">
5119 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5120</div>
5121
5122<div class="doc_text">
5123
5124<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005125<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +00005126 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005127</pre>
5128
5129<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005130<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +00005131 locations, allowing garbage collector implementations that require read
5132 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005133
5134<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005135<p>The second argument is the address to read from, which should be an address
Bill Wendlingf85859d2009-07-20 02:29:24 +00005136 allocated from the garbage collector. The first object is a pointer to the
5137 start of the referenced object, if needed by the language runtime (otherwise
5138 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005139
5140<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005141<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +00005142 instruction, but may be replaced with substantially more complex code by the
5143 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5144 may only be used in a function which <a href="#gc">specifies a GC
5145 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005146
5147</div>
5148
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005149<!-- _______________________________________________________________________ -->
5150<div class="doc_subsubsection">
5151 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5152</div>
5153
5154<div class="doc_text">
5155
5156<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005157<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +00005158 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005159</pre>
5160
5161<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005162<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +00005163 locations, allowing garbage collector implementations that require write
5164 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005165
5166<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005167<p>The first argument is the reference to store, the second is the start of the
Bill Wendlingf85859d2009-07-20 02:29:24 +00005168 object to store it to, and the third is the address of the field of Obj to
5169 store to. If the runtime does not require a pointer to the object, Obj may
5170 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005171
5172<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005173<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +00005174 instruction, but may be replaced with substantially more complex code by the
5175 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5176 may only be used in a function which <a href="#gc">specifies a GC
5177 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005178
5179</div>
5180
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005181<!-- ======================================================================= -->
5182<div class="doc_subsection">
5183 <a name="int_codegen">Code Generator Intrinsics</a>
5184</div>
5185
5186<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00005187
5188<p>These intrinsics are provided by LLVM to expose special features that may
5189 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005190
5191</div>
5192
5193<!-- _______________________________________________________________________ -->
5194<div class="doc_subsubsection">
5195 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5196</div>
5197
5198<div class="doc_text">
5199
5200<h5>Syntax:</h5>
5201<pre>
5202 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5203</pre>
5204
5205<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005206<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5207 target-specific value indicating the return address of the current function
5208 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005209
5210<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005211<p>The argument to this intrinsic indicates which function to return the address
5212 for. Zero indicates the calling function, one indicates its caller, etc.
5213 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005214
5215<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005216<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5217 indicating the return address of the specified call frame, or zero if it
5218 cannot be identified. The value returned by this intrinsic is likely to be
5219 incorrect or 0 for arguments other than zero, so it should only be used for
5220 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005221
Bill Wendlingf85859d2009-07-20 02:29:24 +00005222<p>Note that calling this intrinsic does not prevent function inlining or other
5223 aggressive transformations, so the value returned may not be that of the
5224 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005225
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005226</div>
5227
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005228<!-- _______________________________________________________________________ -->
5229<div class="doc_subsubsection">
5230 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5231</div>
5232
5233<div class="doc_text">
5234
5235<h5>Syntax:</h5>
5236<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +00005237 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005238</pre>
5239
5240<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005241<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5242 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005243
5244<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005245<p>The argument to this intrinsic indicates which function to return the frame
5246 pointer for. Zero indicates the calling function, one indicates its caller,
5247 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005248
5249<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005250<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5251 indicating the frame address of the specified call frame, or zero if it
5252 cannot be identified. The value returned by this intrinsic is likely to be
5253 incorrect or 0 for arguments other than zero, so it should only be used for
5254 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005255
Bill Wendlingf85859d2009-07-20 02:29:24 +00005256<p>Note that calling this intrinsic does not prevent function inlining or other
5257 aggressive transformations, so the value returned may not be that of the
5258 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005259
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005260</div>
5261
5262<!-- _______________________________________________________________________ -->
5263<div class="doc_subsubsection">
5264 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5265</div>
5266
5267<div class="doc_text">
5268
5269<h5>Syntax:</h5>
5270<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +00005271 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005272</pre>
5273
5274<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005275<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5276 of the function stack, for use
5277 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5278 useful for implementing language features like scoped automatic variable
5279 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005280
5281<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005282<p>This intrinsic returns a opaque pointer value that can be passed
5283 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5284 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5285 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5286 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5287 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5288 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005289
5290</div>
5291
5292<!-- _______________________________________________________________________ -->
5293<div class="doc_subsubsection">
5294 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5295</div>
5296
5297<div class="doc_text">
5298
5299<h5>Syntax:</h5>
5300<pre>
5301 declare void @llvm.stackrestore(i8 * %ptr)
5302</pre>
5303
5304<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005305<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5306 the function stack to the state it was in when the
5307 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5308 executed. This is useful for implementing language features like scoped
5309 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005310
5311<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005312<p>See the description
5313 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005314
5315</div>
5316
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005317<!-- _______________________________________________________________________ -->
5318<div class="doc_subsubsection">
5319 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5320</div>
5321
5322<div class="doc_text">
5323
5324<h5>Syntax:</h5>
5325<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +00005326 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005327</pre>
5328
5329<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005330<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5331 insert a prefetch instruction if supported; otherwise, it is a noop.
5332 Prefetches have no effect on the behavior of the program but can change its
5333 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005334
5335<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005336<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5337 specifier determining if the fetch should be for a read (0) or write (1),
5338 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5339 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5340 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005341
5342<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005343<p>This intrinsic does not modify the behavior of the program. In particular,
5344 prefetches cannot trap and do not produce a value. On targets that support
5345 this intrinsic, the prefetch can provide hints to the processor cache for
5346 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005347
5348</div>
5349
5350<!-- _______________________________________________________________________ -->
5351<div class="doc_subsubsection">
5352 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5353</div>
5354
5355<div class="doc_text">
5356
5357<h5>Syntax:</h5>
5358<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +00005359 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005360</pre>
5361
5362<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005363<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5364 Counter (PC) in a region of code to simulators and other tools. The method
5365 is target specific, but it is expected that the marker will use exported
5366 symbols to transmit the PC of the marker. The marker makes no guarantees
5367 that it will remain with any specific instruction after optimizations. It is
5368 possible that the presence of a marker will inhibit optimizations. The
5369 intended use is to be inserted after optimizations to allow correlations of
5370 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005371
5372<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005373<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005374
5375<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005376<p>This intrinsic does not modify the behavior of the program. Backends that do
5377 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005378
5379</div>
5380
5381<!-- _______________________________________________________________________ -->
5382<div class="doc_subsubsection">
5383 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5384</div>
5385
5386<div class="doc_text">
5387
5388<h5>Syntax:</h5>
5389<pre>
5390 declare i64 @llvm.readcyclecounter( )
5391</pre>
5392
5393<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005394<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5395 counter register (or similar low latency, high accuracy clocks) on those
5396 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5397 should map to RPCC. As the backing counters overflow quickly (on the order
5398 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005399
5400<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005401<p>When directly supported, reading the cycle counter should not modify any
5402 memory. Implementations are allowed to either return a application specific
5403 value or a system wide value. On backends without support, this is lowered
5404 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005405
5406</div>
5407
5408<!-- ======================================================================= -->
5409<div class="doc_subsection">
5410 <a name="int_libc">Standard C Library Intrinsics</a>
5411</div>
5412
5413<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00005414
5415<p>LLVM provides intrinsics for a few important standard C library functions.
5416 These intrinsics allow source-language front-ends to pass information about
5417 the alignment of the pointer arguments to the code generator, providing
5418 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005419
5420</div>
5421
5422<!-- _______________________________________________________________________ -->
5423<div class="doc_subsubsection">
5424 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5425</div>
5426
5427<div class="doc_text">
5428
5429<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005430<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5431 integer bit width. Not all targets support all bit widths however.</p>
5432
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005433<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +00005434 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +00005435 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +00005436 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5437 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005438 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5439 i32 &lt;len&gt;, i32 &lt;align&gt;)
5440 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5441 i64 &lt;len&gt;, i32 &lt;align&gt;)
5442</pre>
5443
5444<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005445<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5446 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005447
Bill Wendlingf85859d2009-07-20 02:29:24 +00005448<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5449 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005450
5451<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005452<p>The first argument is a pointer to the destination, the second is a pointer
5453 to the source. The third argument is an integer argument specifying the
5454 number of bytes to copy, and the fourth argument is the alignment of the
5455 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005456
Bill Wendlingf85859d2009-07-20 02:29:24 +00005457<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5458 then the caller guarantees that both the source and destination pointers are
5459 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005460
5461<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005462<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5463 source location to the destination location, which are not allowed to
5464 overlap. It copies "len" bytes of memory over. If the argument is known to
5465 be aligned to some boundary, this can be specified as the fourth argument,
5466 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005467
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005468</div>
5469
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005470<!-- _______________________________________________________________________ -->
5471<div class="doc_subsubsection">
5472 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5473</div>
5474
5475<div class="doc_text">
5476
5477<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +00005478<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +00005479 width. Not all targets support all bit widths however.</p>
5480
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005481<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +00005482 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +00005483 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +00005484 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5485 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005486 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5487 i32 &lt;len&gt;, i32 &lt;align&gt;)
5488 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5489 i64 &lt;len&gt;, i32 &lt;align&gt;)
5490</pre>
5491
5492<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005493<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5494 source location to the destination location. It is similar to the
5495 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5496 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005497
Bill Wendlingf85859d2009-07-20 02:29:24 +00005498<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5499 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005500
5501<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005502<p>The first argument is a pointer to the destination, the second is a pointer
5503 to the source. The third argument is an integer argument specifying the
5504 number of bytes to copy, and the fourth argument is the alignment of the
5505 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005506
Bill Wendlingf85859d2009-07-20 02:29:24 +00005507<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5508 then the caller guarantees that the source and destination pointers are
5509 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005510
5511<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005512<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5513 source location to the destination location, which may overlap. It copies
5514 "len" bytes of memory over. If the argument is known to be aligned to some
5515 boundary, this can be specified as the fourth argument, otherwise it should
5516 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005517
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005518</div>
5519
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005520<!-- _______________________________________________________________________ -->
5521<div class="doc_subsubsection">
5522 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5523</div>
5524
5525<div class="doc_text">
5526
5527<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +00005528<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +00005529 width. Not all targets support all bit widths however.</p>
5530
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005531<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +00005532 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +00005533 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +00005534 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5535 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005536 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5537 i32 &lt;len&gt;, i32 &lt;align&gt;)
5538 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5539 i64 &lt;len&gt;, i32 &lt;align&gt;)
5540</pre>
5541
5542<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005543<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5544 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005545
Bill Wendlingf85859d2009-07-20 02:29:24 +00005546<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5547 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005548
5549<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005550<p>The first argument is a pointer to the destination to fill, the second is the
5551 byte value to fill it with, the third argument is an integer argument
5552 specifying the number of bytes to fill, and the fourth argument is the known
5553 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005554
Bill Wendlingf85859d2009-07-20 02:29:24 +00005555<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5556 then the caller guarantees that the destination pointer is aligned to that
5557 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005558
5559<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005560<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5561 at the destination location. If the argument is known to be aligned to some
5562 boundary, this can be specified as the fourth argument, otherwise it should
5563 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005564
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005565</div>
5566
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005567<!-- _______________________________________________________________________ -->
5568<div class="doc_subsubsection">
5569 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5570</div>
5571
5572<div class="doc_text">
5573
5574<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005575<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5576 floating point or vector of floating point type. Not all targets support all
5577 types however.</p>
5578
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005579<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +00005580 declare float @llvm.sqrt.f32(float %Val)
5581 declare double @llvm.sqrt.f64(double %Val)
5582 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5583 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5584 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005585</pre>
5586
5587<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005588<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5589 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5590 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5591 behavior for negative numbers other than -0.0 (which allows for better
5592 optimization, because there is no need to worry about errno being
5593 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005594
5595<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005596<p>The argument and return value are floating point numbers of the same
5597 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005598
5599<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005600<p>This function returns the sqrt of the specified operand if it is a
5601 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005602
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005603</div>
5604
5605<!-- _______________________________________________________________________ -->
5606<div class="doc_subsubsection">
5607 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5608</div>
5609
5610<div class="doc_text">
5611
5612<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005613<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5614 floating point or vector of floating point type. Not all targets support all
5615 types however.</p>
5616
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005617<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +00005618 declare float @llvm.powi.f32(float %Val, i32 %power)
5619 declare double @llvm.powi.f64(double %Val, i32 %power)
5620 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5621 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5622 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005623</pre>
5624
5625<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005626<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5627 specified (positive or negative) power. The order of evaluation of
5628 multiplications is not defined. When a vector of floating point type is
5629 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005630
5631<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005632<p>The second argument is an integer power, and the first is a value to raise to
5633 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005634
5635<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005636<p>This function returns the first value raised to the second power with an
5637 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005638
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005639</div>
5640
Dan Gohman361079c2007-10-15 20:30:11 +00005641<!-- _______________________________________________________________________ -->
5642<div class="doc_subsubsection">
5643 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5644</div>
5645
5646<div class="doc_text">
5647
5648<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005649<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5650 floating point or vector of floating point type. Not all targets support all
5651 types however.</p>
5652
Dan Gohman361079c2007-10-15 20:30:11 +00005653<pre>
5654 declare float @llvm.sin.f32(float %Val)
5655 declare double @llvm.sin.f64(double %Val)
5656 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5657 declare fp128 @llvm.sin.f128(fp128 %Val)
5658 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5659</pre>
5660
5661<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005662<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005663
5664<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005665<p>The argument and return value are floating point numbers of the same
5666 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005667
5668<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005669<p>This function returns the sine of the specified operand, returning the same
5670 values as the libm <tt>sin</tt> functions would, and handles error conditions
5671 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005672
Dan Gohman361079c2007-10-15 20:30:11 +00005673</div>
5674
5675<!-- _______________________________________________________________________ -->
5676<div class="doc_subsubsection">
5677 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5678</div>
5679
5680<div class="doc_text">
5681
5682<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005683<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5684 floating point or vector of floating point type. Not all targets support all
5685 types however.</p>
5686
Dan Gohman361079c2007-10-15 20:30:11 +00005687<pre>
5688 declare float @llvm.cos.f32(float %Val)
5689 declare double @llvm.cos.f64(double %Val)
5690 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5691 declare fp128 @llvm.cos.f128(fp128 %Val)
5692 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5693</pre>
5694
5695<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005696<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005697
5698<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005699<p>The argument and return value are floating point numbers of the same
5700 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005701
5702<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005703<p>This function returns the cosine of the specified operand, returning the same
5704 values as the libm <tt>cos</tt> functions would, and handles error conditions
5705 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005706
Dan Gohman361079c2007-10-15 20:30:11 +00005707</div>
5708
5709<!-- _______________________________________________________________________ -->
5710<div class="doc_subsubsection">
5711 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5712</div>
5713
5714<div class="doc_text">
5715
5716<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005717<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5718 floating point or vector of floating point type. Not all targets support all
5719 types however.</p>
5720
Dan Gohman361079c2007-10-15 20:30:11 +00005721<pre>
5722 declare float @llvm.pow.f32(float %Val, float %Power)
5723 declare double @llvm.pow.f64(double %Val, double %Power)
5724 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5725 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5726 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5727</pre>
5728
5729<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005730<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5731 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005732
5733<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005734<p>The second argument is a floating point power, and the first is a value to
5735 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005736
5737<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005738<p>This function returns the first value raised to the second power, returning
5739 the same values as the libm <tt>pow</tt> functions would, and handles error
5740 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +00005741
Dan Gohman361079c2007-10-15 20:30:11 +00005742</div>
5743
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005744<!-- ======================================================================= -->
5745<div class="doc_subsection">
5746 <a name="int_manip">Bit Manipulation Intrinsics</a>
5747</div>
5748
5749<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00005750
5751<p>LLVM provides intrinsics for a few important bit manipulation operations.
5752 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005753
5754</div>
5755
5756<!-- _______________________________________________________________________ -->
5757<div class="doc_subsubsection">
5758 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5759</div>
5760
5761<div class="doc_text">
5762
5763<h5>Syntax:</h5>
5764<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +00005765 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5766
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005767<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +00005768 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5769 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5770 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005771</pre>
5772
5773<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005774<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5775 values with an even number of bytes (positive multiple of 16 bits). These
5776 are useful for performing operations on data that is not in the target's
5777 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005778
5779<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005780<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
5781 and low byte of the input i16 swapped. Similarly,
5782 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
5783 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
5784 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
5785 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
5786 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
5787 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005788
5789</div>
5790
5791<!-- _______________________________________________________________________ -->
5792<div class="doc_subsubsection">
5793 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5794</div>
5795
5796<div class="doc_text">
5797
5798<h5>Syntax:</h5>
5799<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +00005800 width. Not all targets support all bit widths however.</p>
5801
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005802<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005803 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +00005804 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005805 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +00005806 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5807 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005808</pre>
5809
5810<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005811<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
5812 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005813
5814<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005815<p>The only argument is the value to be counted. The argument may be of any
5816 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005817
5818<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005819<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005820
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005821</div>
5822
5823<!-- _______________________________________________________________________ -->
5824<div class="doc_subsubsection">
5825 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5826</div>
5827
5828<div class="doc_text">
5829
5830<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005831<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5832 integer bit width. Not all targets support all bit widths however.</p>
5833
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005834<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +00005835 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5836 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005837 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +00005838 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5839 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005840</pre>
5841
5842<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005843<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5844 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005845
5846<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005847<p>The only argument is the value to be counted. The argument may be of any
5848 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005849
5850<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005851<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
5852 zeros in a variable. If the src == 0 then the result is the size in bits of
5853 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005854
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005855</div>
5856
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005857<!-- _______________________________________________________________________ -->
5858<div class="doc_subsubsection">
5859 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5860</div>
5861
5862<div class="doc_text">
5863
5864<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005865<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5866 integer bit width. Not all targets support all bit widths however.</p>
5867
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005868<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +00005869 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5870 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005871 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +00005872 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5873 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005874</pre>
5875
5876<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005877<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5878 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005879
5880<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005881<p>The only argument is the value to be counted. The argument may be of any
5882 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005883
5884<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005885<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
5886 zeros in a variable. If the src == 0 then the result is the size in bits of
5887 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005888
Dan Gohmanf17a25c2007-07-18 16:29:46 +00005889</div>
5890
Bill Wendling3e1258b2009-02-08 04:04:40 +00005891<!-- ======================================================================= -->
5892<div class="doc_subsection">
5893 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
5894</div>
5895
5896<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00005897
5898<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +00005899
5900</div>
5901
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005902<!-- _______________________________________________________________________ -->
5903<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +00005904 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005905</div>
5906
5907<div class="doc_text">
5908
5909<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005910<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005911 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005912
5913<pre>
5914 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
5915 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5916 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
5917</pre>
5918
5919<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005920<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00005921 a signed addition of the two arguments, and indicate whether an overflow
5922 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005923
5924<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005925<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +00005926 be of integer types of any bit width, but they must have the same bit
5927 width. The second element of the result structure must be of
5928 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
5929 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005930
5931<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005932<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00005933 a signed addition of the two variables. They return a structure &mdash; the
5934 first element of which is the signed summation, and the second element of
5935 which is a bit specifying if the signed summation resulted in an
5936 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005937
5938<h5>Examples:</h5>
5939<pre>
5940 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5941 %sum = extractvalue {i32, i1} %res, 0
5942 %obit = extractvalue {i32, i1} %res, 1
5943 br i1 %obit, label %overflow, label %normal
5944</pre>
5945
5946</div>
5947
5948<!-- _______________________________________________________________________ -->
5949<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +00005950 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005951</div>
5952
5953<div class="doc_text">
5954
5955<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005956<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00005957 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005958
5959<pre>
5960 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
5961 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
5962 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
5963</pre>
5964
5965<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005966<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00005967 an unsigned addition of the two arguments, and indicate whether a carry
5968 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005969
5970<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005971<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +00005972 be of integer types of any bit width, but they must have the same bit
5973 width. The second element of the result structure must be of
5974 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
5975 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005976
5977<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005978<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00005979 an unsigned addition of the two arguments. They return a structure &mdash;
5980 the first element of which is the sum, and the second element of which is a
5981 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005982
5983<h5>Examples:</h5>
5984<pre>
5985 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
5986 %sum = extractvalue {i32, i1} %res, 0
5987 %obit = extractvalue {i32, i1} %res, 1
5988 br i1 %obit, label %carry, label %normal
5989</pre>
5990
5991</div>
5992
5993<!-- _______________________________________________________________________ -->
5994<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +00005995 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00005996</div>
5997
5998<div class="doc_text">
5999
6000<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006001<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006002 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006003
6004<pre>
6005 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6006 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6007 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6008</pre>
6009
6010<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006011<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006012 a signed subtraction of the two arguments, and indicate whether an overflow
6013 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006014
6015<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006016<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +00006017 be of integer types of any bit width, but they must have the same bit
6018 width. The second element of the result structure must be of
6019 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6020 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006021
6022<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006023<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006024 a signed subtraction of the two arguments. They return a structure &mdash;
6025 the first element of which is the subtraction, and the second element of
6026 which is a bit specifying if the signed subtraction resulted in an
6027 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006028
6029<h5>Examples:</h5>
6030<pre>
6031 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6032 %sum = extractvalue {i32, i1} %res, 0
6033 %obit = extractvalue {i32, i1} %res, 1
6034 br i1 %obit, label %overflow, label %normal
6035</pre>
6036
6037</div>
6038
6039<!-- _______________________________________________________________________ -->
6040<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +00006041 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006042</div>
6043
6044<div class="doc_text">
6045
6046<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006047<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006048 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006049
6050<pre>
6051 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6052 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6053 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6054</pre>
6055
6056<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006057<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006058 an unsigned subtraction of the two arguments, and indicate whether an
6059 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006060
6061<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006062<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +00006063 be of integer types of any bit width, but they must have the same bit
6064 width. The second element of the result structure must be of
6065 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6066 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006067
6068<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006069<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006070 an unsigned subtraction of the two arguments. They return a structure &mdash;
6071 the first element of which is the subtraction, and the second element of
6072 which is a bit specifying if the unsigned subtraction resulted in an
6073 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006074
6075<h5>Examples:</h5>
6076<pre>
6077 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6078 %sum = extractvalue {i32, i1} %res, 0
6079 %obit = extractvalue {i32, i1} %res, 1
6080 br i1 %obit, label %overflow, label %normal
6081</pre>
6082
6083</div>
6084
6085<!-- _______________________________________________________________________ -->
6086<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +00006087 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006088</div>
6089
6090<div class="doc_text">
6091
6092<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006093<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006094 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006095
6096<pre>
6097 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6098 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6099 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6100</pre>
6101
6102<h5>Overview:</h5>
6103
6104<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006105 a signed multiplication of the two arguments, and indicate whether an
6106 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006107
6108<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006109<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +00006110 be of integer types of any bit width, but they must have the same bit
6111 width. The second element of the result structure must be of
6112 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6113 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006114
6115<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006116<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006117 a signed multiplication of the two arguments. They return a structure &mdash;
6118 the first element of which is the multiplication, and the second element of
6119 which is a bit specifying if the signed multiplication resulted in an
6120 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +00006121
6122<h5>Examples:</h5>
6123<pre>
6124 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6125 %sum = extractvalue {i32, i1} %res, 0
6126 %obit = extractvalue {i32, i1} %res, 1
6127 br i1 %obit, label %overflow, label %normal
6128</pre>
6129
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006130</div>
6131
Bill Wendlingbda98b62009-02-08 23:00:09 +00006132<!-- _______________________________________________________________________ -->
6133<div class="doc_subsubsection">
6134 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6135</div>
6136
6137<div class="doc_text">
6138
6139<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006140<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006141 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006142
6143<pre>
6144 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6145 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6146 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6147</pre>
6148
6149<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006150<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006151 a unsigned multiplication of the two arguments, and indicate whether an
6152 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006153
6154<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006155<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +00006156 be of integer types of any bit width, but they must have the same bit
6157 width. The second element of the result structure must be of
6158 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6159 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006160
6161<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006162<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +00006163 an unsigned multiplication of the two arguments. They return a structure
6164 &mdash; the first element of which is the multiplication, and the second
6165 element of which is a bit specifying if the unsigned multiplication resulted
6166 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +00006167
6168<h5>Examples:</h5>
6169<pre>
6170 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6171 %sum = extractvalue {i32, i1} %res, 0
6172 %obit = extractvalue {i32, i1} %res, 1
6173 br i1 %obit, label %overflow, label %normal
6174</pre>
6175
6176</div>
6177
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006178<!-- ======================================================================= -->
6179<div class="doc_subsection">
6180 <a name="int_debugger">Debugger Intrinsics</a>
6181</div>
6182
6183<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006184
Bill Wendlingf85859d2009-07-20 02:29:24 +00006185<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6186 prefix), are described in
6187 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6188 Level Debugging</a> document.</p>
6189
6190</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006191
6192<!-- ======================================================================= -->
6193<div class="doc_subsection">
6194 <a name="int_eh">Exception Handling Intrinsics</a>
6195</div>
6196
6197<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006198
6199<p>The LLVM exception handling intrinsics (which all start with
6200 <tt>llvm.eh.</tt> prefix), are described in
6201 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6202 Handling</a> document.</p>
6203
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006204</div>
6205
6206<!-- ======================================================================= -->
6207<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +00006208 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +00006209</div>
6210
6211<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006212
6213<p>This intrinsic makes it possible to excise one parameter, marked with
6214 the <tt>nest</tt> attribute, from a function. The result is a callable
6215 function pointer lacking the nest parameter - the caller does not need to
6216 provide a value for it. Instead, the value to use is stored in advance in a
6217 "trampoline", a block of memory usually allocated on the stack, which also
6218 contains code to splice the nest value into the argument list. This is used
6219 to implement the GCC nested function address extension.</p>
6220
6221<p>For example, if the function is
6222 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6223 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6224 follows:</p>
6225
6226<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +00006227<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +00006228 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6229 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6230 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6231 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +00006232</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006233</div>
6234
6235<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6236 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6237
Duncan Sands38947cd2007-07-27 12:58:54 +00006238</div>
6239
6240<!-- _______________________________________________________________________ -->
6241<div class="doc_subsubsection">
6242 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6243</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006244
Duncan Sands38947cd2007-07-27 12:58:54 +00006245<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006246
Duncan Sands38947cd2007-07-27 12:58:54 +00006247<h5>Syntax:</h5>
6248<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006249 declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands38947cd2007-07-27 12:58:54 +00006250</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006251
Duncan Sands38947cd2007-07-27 12:58:54 +00006252<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006253<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6254 function pointer suitable for executing it.</p>
6255
Duncan Sands38947cd2007-07-27 12:58:54 +00006256<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006257<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6258 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6259 sufficiently aligned block of memory; this memory is written to by the
6260 intrinsic. Note that the size and the alignment are target-specific - LLVM
6261 currently provides no portable way of determining them, so a front-end that
6262 generates this intrinsic needs to have some target-specific knowledge.
6263 The <tt>func</tt> argument must hold a function bitcast to
6264 an <tt>i8*</tt>.</p>
6265
Duncan Sands38947cd2007-07-27 12:58:54 +00006266<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006267<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6268 dependent code, turning it into a function. A pointer to this function is
6269 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6270 function pointer type</a> before being called. The new function's signature
6271 is the same as that of <tt>func</tt> with any arguments marked with
6272 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6273 is allowed, and it must be of pointer type. Calling the new function is
6274 equivalent to calling <tt>func</tt> with the same argument list, but
6275 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6276 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6277 by <tt>tramp</tt> is modified, then the effect of any later call to the
6278 returned function pointer is undefined.</p>
6279
Duncan Sands38947cd2007-07-27 12:58:54 +00006280</div>
6281
6282<!-- ======================================================================= -->
6283<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +00006284 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6285</div>
6286
6287<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +00006288
Bill Wendlingf85859d2009-07-20 02:29:24 +00006289<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6290 hardware constructs for atomic operations and memory synchronization. This
6291 provides an interface to the hardware, not an interface to the programmer. It
6292 is aimed at a low enough level to allow any programming models or APIs
6293 (Application Programming Interfaces) which need atomic behaviors to map
6294 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6295 hardware provides a "universal IR" for source languages, it also provides a
6296 starting point for developing a "universal" atomic operation and
6297 synchronization IR.</p>
6298
6299<p>These do <em>not</em> form an API such as high-level threading libraries,
6300 software transaction memory systems, atomic primitives, and intrinsic
6301 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6302 application libraries. The hardware interface provided by LLVM should allow
6303 a clean implementation of all of these APIs and parallel programming models.
6304 No one model or paradigm should be selected above others unless the hardware
6305 itself ubiquitously does so.</p>
6306
Andrew Lenharth785610d2008-02-16 01:24:58 +00006307</div>
6308
6309<!-- _______________________________________________________________________ -->
6310<div class="doc_subsubsection">
6311 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6312</div>
6313<div class="doc_text">
6314<h5>Syntax:</h5>
6315<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006316 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 +00006317</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006318
Andrew Lenharth785610d2008-02-16 01:24:58 +00006319<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006320<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6321 specific pairs of memory access types.</p>
6322
Andrew Lenharth785610d2008-02-16 01:24:58 +00006323<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006324<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6325 The first four arguments enables a specific barrier as listed below. The
6326 fith argument specifies that the barrier applies to io or device or uncached
6327 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +00006328
Bill Wendlingf85859d2009-07-20 02:29:24 +00006329<ul>
6330 <li><tt>ll</tt>: load-load barrier</li>
6331 <li><tt>ls</tt>: load-store barrier</li>
6332 <li><tt>sl</tt>: store-load barrier</li>
6333 <li><tt>ss</tt>: store-store barrier</li>
6334 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6335</ul>
6336
Andrew Lenharth785610d2008-02-16 01:24:58 +00006337<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006338<p>This intrinsic causes the system to enforce some ordering constraints upon
6339 the loads and stores of the program. This barrier does not
6340 indicate <em>when</em> any events will occur, it only enforces
6341 an <em>order</em> in which they occur. For any of the specified pairs of load
6342 and store operations (f.ex. load-load, or store-load), all of the first
6343 operations preceding the barrier will complete before any of the second
6344 operations succeeding the barrier begin. Specifically the semantics for each
6345 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +00006346
Bill Wendlingf85859d2009-07-20 02:29:24 +00006347<ul>
6348 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6349 after the barrier begins.</li>
6350 <li><tt>ls</tt>: All loads before the barrier must complete before any
6351 store after the barrier begins.</li>
6352 <li><tt>ss</tt>: All stores before the barrier must complete before any
6353 store after the barrier begins.</li>
6354 <li><tt>sl</tt>: All stores before the barrier must complete before any
6355 load after the barrier begins.</li>
6356</ul>
6357
6358<p>These semantics are applied with a logical "and" behavior when more than one
6359 is enabled in a single memory barrier intrinsic.</p>
6360
6361<p>Backends may implement stronger barriers than those requested when they do
6362 not support as fine grained a barrier as requested. Some architectures do
6363 not need all types of barriers and on such architectures, these become
6364 noops.</p>
6365
Andrew Lenharth785610d2008-02-16 01:24:58 +00006366<h5>Example:</h5>
6367<pre>
6368%ptr = malloc i32
6369 store i32 4, %ptr
6370
6371%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6372 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6373 <i>; guarantee the above finishes</i>
6374 store i32 8, %ptr <i>; before this begins</i>
6375</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006376
Andrew Lenharth785610d2008-02-16 01:24:58 +00006377</div>
6378
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006379<!-- _______________________________________________________________________ -->
6380<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006381 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006382</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006383
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006384<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006385
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006386<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006387<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6388 any integer bit width and for different address spaces. Not all targets
6389 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006390
6391<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006392 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6393 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6394 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6395 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 +00006396</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006397
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006398<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006399<p>This loads a value in memory and compares it to a given value. If they are
6400 equal, it stores a new value into the memory.</p>
6401
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006402<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006403<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6404 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6405 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6406 this integer type. While any bit width integer may be used, targets may only
6407 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006408
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006409<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006410<p>This entire intrinsic must be executed atomically. It first loads the value
6411 in memory pointed to by <tt>ptr</tt> and compares it with the
6412 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6413 memory. The loaded value is yielded in all cases. This provides the
6414 equivalent of an atomic compare-and-swap operation within the SSA
6415 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006416
Bill Wendlingf85859d2009-07-20 02:29:24 +00006417<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006418<pre>
6419%ptr = malloc i32
6420 store i32 4, %ptr
6421
6422%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +00006423%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006424 <i>; yields {i32}:result1 = 4</i>
6425%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6426%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6427
6428%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +00006429%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006430 <i>; yields {i32}:result2 = 8</i>
6431%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6432
6433%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6434</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006435
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006436</div>
6437
6438<!-- _______________________________________________________________________ -->
6439<div class="doc_subsubsection">
6440 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6441</div>
6442<div class="doc_text">
6443<h5>Syntax:</h5>
6444
Bill Wendlingf85859d2009-07-20 02:29:24 +00006445<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6446 integer bit width. Not all targets support all bit widths however.</p>
6447
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006448<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006449 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6450 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6451 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6452 declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006453</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006454
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006455<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006456<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6457 the value from memory. It then stores the value in <tt>val</tt> in the memory
6458 at <tt>ptr</tt>.</p>
6459
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006460<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006461<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6462 the <tt>val</tt> argument and the result must be integers of the same bit
6463 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6464 integer type. The targets may only lower integer representations they
6465 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006466
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006467<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006468<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6469 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6470 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006471
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006472<h5>Examples:</h5>
6473<pre>
6474%ptr = malloc i32
6475 store i32 4, %ptr
6476
6477%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +00006478%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006479 <i>; yields {i32}:result1 = 4</i>
6480%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6481%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6482
6483%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +00006484%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006485 <i>; yields {i32}:result2 = 8</i>
6486
6487%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6488%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6489</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006490
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006491</div>
6492
6493<!-- _______________________________________________________________________ -->
6494<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006495 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006496
6497</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006498
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006499<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006500
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006501<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006502<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6503 any integer bit width. Not all targets support all bit widths however.</p>
6504
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006505<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006506 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6507 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6508 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6509 declare i64 @llvm.atomic.load.add.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006510</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006511
Bill Wendlingf85859d2009-07-20 02:29:24 +00006512<h5>Overview:</h5>
6513<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6514 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6515
6516<h5>Arguments:</h5>
6517<p>The intrinsic takes two arguments, the first a pointer to an integer value
6518 and the second an integer value. The result is also an integer value. These
6519 integer types can have any bit width, but they must all have the same bit
6520 width. The targets may only lower integer representations they support.</p>
6521
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006522<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006523<p>This intrinsic does a series of operations atomically. It first loads the
6524 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6525 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006526
6527<h5>Examples:</h5>
6528<pre>
6529%ptr = malloc i32
6530 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +00006531%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006532 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006533%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006534 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006535%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006536 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006537%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006538</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006539
Andrew Lenharthe44f3902008-02-21 06:45:13 +00006540</div>
6541
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006542<!-- _______________________________________________________________________ -->
6543<div class="doc_subsubsection">
6544 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6545
6546</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006547
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006548<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006549
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006550<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006551<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6552 any integer bit width and for different address spaces. Not all targets
6553 support all bit widths however.</p>
6554
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006555<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006556 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6557 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6558 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6559 declare i64 @llvm.atomic.load.sub.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006560</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006561
Bill Wendlingf85859d2009-07-20 02:29:24 +00006562<h5>Overview:</h5>
6563<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6564 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6565
6566<h5>Arguments:</h5>
6567<p>The intrinsic takes two arguments, the first a pointer to an integer value
6568 and the second an integer value. The result is also an integer value. These
6569 integer types can have any bit width, but they must all have the same bit
6570 width. The targets may only lower integer representations they support.</p>
6571
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006572<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006573<p>This intrinsic does a series of operations atomically. It first loads the
6574 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6575 result to <tt>ptr</tt>. It yields the original value stored
6576 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006577
6578<h5>Examples:</h5>
6579<pre>
6580%ptr = malloc i32
6581 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +00006582%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006583 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006584%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006585 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006586%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006587 <i>; yields {i32}:result3 = 2</i>
6588%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6589</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006590
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006591</div>
6592
6593<!-- _______________________________________________________________________ -->
6594<div class="doc_subsubsection">
6595 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6596 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6597 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6598 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006599</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006600
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006601<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006602
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006603<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006604<p>These are overloaded intrinsics. You can
6605 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6606 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6607 bit width and for different address spaces. Not all targets support all bit
6608 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006609
Bill Wendlingf85859d2009-07-20 02:29:24 +00006610<pre>
6611 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6612 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6613 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6614 declare i64 @llvm.atomic.load.and.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006615</pre>
6616
6617<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006618 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6619 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6620 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6621 declare i64 @llvm.atomic.load.or.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006622</pre>
6623
6624<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006625 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6626 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6627 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6628 declare i64 @llvm.atomic.load.nand.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006629</pre>
6630
6631<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006632 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6633 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6634 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6635 declare i64 @llvm.atomic.load.xor.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006636</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006637
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006638<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006639<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6640 the value stored in memory at <tt>ptr</tt>. It yields the original value
6641 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006642
Bill Wendlingf85859d2009-07-20 02:29:24 +00006643<h5>Arguments:</h5>
6644<p>These intrinsics take two arguments, the first a pointer to an integer value
6645 and the second an integer value. The result is also an integer value. These
6646 integer types can have any bit width, but they must all have the same bit
6647 width. The targets may only lower integer representations they support.</p>
6648
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006649<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006650<p>These intrinsics does a series of operations atomically. They first load the
6651 value stored at <tt>ptr</tt>. They then do the bitwise
6652 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6653 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006654
6655<h5>Examples:</h5>
6656<pre>
6657%ptr = malloc i32
6658 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +00006659%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006660 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006661%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006662 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006663%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006664 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006665%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006666 <i>; yields {i32}:result3 = FF</i>
6667%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6668</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006669
Bill Wendlingf85859d2009-07-20 02:29:24 +00006670</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006671
6672<!-- _______________________________________________________________________ -->
6673<div class="doc_subsubsection">
6674 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6675 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6676 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6677 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006678</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006679
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006680<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006681
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006682<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006683<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6684 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6685 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6686 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006687
Bill Wendlingf85859d2009-07-20 02:29:24 +00006688<pre>
6689 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6690 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6691 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6692 declare i64 @llvm.atomic.load.max.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006693</pre>
6694
6695<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006696 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6697 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6698 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6699 declare i64 @llvm.atomic.load.min.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006700</pre>
6701
6702<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006703 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6704 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6705 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6706 declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006707</pre>
6708
6709<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006710 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6711 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6712 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6713 declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006714</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006715
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006716<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006717<p>These intrinsics takes the signed or unsigned minimum or maximum of
6718 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6719 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006720
Bill Wendlingf85859d2009-07-20 02:29:24 +00006721<h5>Arguments:</h5>
6722<p>These intrinsics take two arguments, the first a pointer to an integer value
6723 and the second an integer value. The result is also an integer value. These
6724 integer types can have any bit width, but they must all have the same bit
6725 width. The targets may only lower integer representations they support.</p>
6726
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006727<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006728<p>These intrinsics does a series of operations atomically. They first load the
6729 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6730 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6731 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006732
6733<h5>Examples:</h5>
6734<pre>
6735%ptr = malloc i32
6736 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +00006737%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006738 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006739%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006740 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006741%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006742 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +00006743%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006744 <i>; yields {i32}:result3 = 8</i>
6745%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6746</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006747
Mon P Wang6bde9ec2008-06-25 08:15:39 +00006748</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +00006749
6750<!-- ======================================================================= -->
6751<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006752 <a name="int_general">General Intrinsics</a>
6753</div>
6754
6755<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006756
6757<p>This class of intrinsics is designed to be generic and has no specific
6758 purpose.</p>
6759
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006760</div>
6761
6762<!-- _______________________________________________________________________ -->
6763<div class="doc_subsubsection">
6764 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6765</div>
6766
6767<div class="doc_text">
6768
6769<h5>Syntax:</h5>
6770<pre>
6771 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6772</pre>
6773
6774<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006775<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006776
6777<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006778<p>The first argument is a pointer to a value, the second is a pointer to a
6779 global string, the third is a pointer to a global string which is the source
6780 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006781
6782<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006783<p>This intrinsic allows annotation of local variables with arbitrary strings.
6784 This can be useful for special purpose optimizations that want to look for
6785 these annotations. These have no other defined use, they are ignored by code
6786 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006787
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006788</div>
6789
Tanya Lattnerb306a9e2007-09-21 22:59:12 +00006790<!-- _______________________________________________________________________ -->
6791<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +00006792 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +00006793</div>
6794
6795<div class="doc_text">
6796
6797<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006798<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6799 any integer bit width.</p>
6800
Tanya Lattnerb306a9e2007-09-21 22:59:12 +00006801<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +00006802 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6803 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6804 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6805 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6806 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 +00006807</pre>
6808
6809<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006810<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +00006811
6812<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006813<p>The first argument is an integer value (result of some expression), the
6814 second is a pointer to a global string, the third is a pointer to a global
6815 string which is the source file name, and the last argument is the line
6816 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +00006817
6818<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006819<p>This intrinsic allows annotations to be put on arbitrary expressions with
6820 arbitrary strings. This can be useful for special purpose optimizations that
6821 want to look for these annotations. These have no other defined use, they
6822 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +00006823
Tanya Lattnerb306a9e2007-09-21 22:59:12 +00006824</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006825
Anton Korobeynikove6e764f2008-01-15 22:31:34 +00006826<!-- _______________________________________________________________________ -->
6827<div class="doc_subsubsection">
6828 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6829</div>
6830
6831<div class="doc_text">
6832
6833<h5>Syntax:</h5>
6834<pre>
6835 declare void @llvm.trap()
6836</pre>
6837
6838<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006839<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +00006840
6841<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006842<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +00006843
6844<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006845<p>This intrinsics is lowered to the target dependent trap instruction. If the
6846 target does not have a trap instruction, this intrinsic will be lowered to
6847 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +00006848
Anton Korobeynikove6e764f2008-01-15 22:31:34 +00006849</div>
6850
Bill Wendlinge4164592008-11-19 05:56:17 +00006851<!-- _______________________________________________________________________ -->
6852<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +00006853 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +00006854</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006855
Bill Wendlinge4164592008-11-19 05:56:17 +00006856<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +00006857
Bill Wendlinge4164592008-11-19 05:56:17 +00006858<h5>Syntax:</h5>
6859<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006860 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +00006861</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006862
Bill Wendlinge4164592008-11-19 05:56:17 +00006863<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006864<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
6865 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
6866 ensure that it is placed on the stack before local variables.</p>
6867
Bill Wendlinge4164592008-11-19 05:56:17 +00006868<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006869<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
6870 arguments. The first argument is the value loaded from the stack
6871 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
6872 that has enough space to hold the value of the guard.</p>
6873
Bill Wendlinge4164592008-11-19 05:56:17 +00006874<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +00006875<p>This intrinsic causes the prologue/epilogue inserter to force the position of
6876 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6877 stack. This is to ensure that if a local variable on the stack is
6878 overwritten, it will destroy the value of the guard. When the function exits,
6879 the guard on the stack is checked against the original guard. If they're
6880 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
6881 function.</p>
6882
Bill Wendlinge4164592008-11-19 05:56:17 +00006883</div>
6884
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006885<!-- *********************************************************************** -->
6886<hr>
6887<address>
6888 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +00006889 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006890 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +00006891 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006892
6893 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6894 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6895 Last modified: $Date$
6896</address>
Chris Lattner08497ce2008-01-04 04:33:49 +00006897
Dan Gohmanf17a25c2007-07-18 16:29:46 +00006898</body>
6899</html>