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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 140ba5d2f288cee79ea3799b420ec83dd6bd6bc1 / . / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
23 <li><a href="#linkage">Linkage Types</a></li>
24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]25 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]26 <li><a href="#globalvars">Global Variables</a></li>
27 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]28 <li><a href="#aliasstructure">Aliases</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]29 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]30 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]31 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]32 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
33 <li><a href="#datalayout">Data Layout</a></li>
34 </ol>
35 </li>
36 <li><a href="#typesystem">Type System</a>
37 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]38 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]39 <li><a href="#t_primitive">Primitive Types</a>
40 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]41 <li><a href="#t_floating">Floating Point Types</a></li>
42 <li><a href="#t_void">Void Type</a></li>
43 <li><a href="#t_label">Label Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]44 </ol>
45 </li>
46 <li><a href="#t_derived">Derived Types</a>
47 <ol>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]48 <li><a href="#t_integer">Integer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]49 <li><a href="#t_array">Array Type</a></li>
50 <li><a href="#t_function">Function Type</a></li>
51 <li><a href="#t_pointer">Pointer Type</a></li>
52 <li><a href="#t_struct">Structure Type</a></li>
53 <li><a href="#t_pstruct">Packed Structure Type</a></li>
54 <li><a href="#t_vector">Vector Type</a></li>
55 <li><a href="#t_opaque">Opaque Type</a></li>
56 </ol>
57 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]58 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]59 </ol>
60 </li>
61 <li><a href="#constants">Constants</a>
62 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]63 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]64 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]65 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
66 <li><a href="#undefvalues">Undefined Values</a></li>
67 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]68 <li><a href="#metadata">Embedded Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]69 </ol>
70 </li>
71 <li><a href="#othervalues">Other Values</a>
72 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]73 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]74 </ol>
75 </li>
76 <li><a href="#instref">Instruction Reference</a>
77 <ol>
78 <li><a href="#terminators">Terminator Instructions</a>
79 <ol>
80 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
81 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
82 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
83 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
84 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
85 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
86 </ol>
87 </li>
88 <li><a href="#binaryops">Binary Operations</a>
89 <ol>
90 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
91 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
92 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
93 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
94 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
95 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
96 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
97 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
98 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
99 </ol>
100 </li>
101 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
102 <ol>
103 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
104 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
105 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
106 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
107 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
108 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
109 </ol>
110 </li>
111 <li><a href="#vectorops">Vector Operations</a>
112 <ol>
113 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
114 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
115 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
116 </ol>
117 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]118 <li><a href="#aggregateops">Aggregate Operations</a>
119 <ol>
120 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
121 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
122 </ol>
123 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]124 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
125 <ol>
126 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
127 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
128 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
129 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
130 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
131 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
132 </ol>
133 </li>
134 <li><a href="#convertops">Conversion Operations</a>
135 <ol>
136 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
137 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
138 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
139 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
140 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
141 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
142 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
143 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
144 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
145 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
146 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
147 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
148 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]149 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]150 <li><a href="#otherops">Other Operations</a>
151 <ol>
152 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
153 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]154 <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
155 <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]156 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
157 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
158 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
159 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
160 </ol>
161 </li>
162 </ol>
163 </li>
164 <li><a href="#intrinsics">Intrinsic Functions</a>
165 <ol>
166 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
167 <ol>
168 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
169 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
170 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
171 </ol>
172 </li>
173 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
174 <ol>
175 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
176 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
177 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
178 </ol>
179 </li>
180 <li><a href="#int_codegen">Code Generator Intrinsics</a>
181 <ol>
182 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
183 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
184 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
185 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
186 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
187 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
188 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
189 </ol>
190 </li>
191 <li><a href="#int_libc">Standard C Library Intrinsics</a>
192 <ol>
193 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
194 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
195 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
196 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
197 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]198 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
199 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
200 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]201 </ol>
202 </li>
203 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
204 <ol>
205 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
206 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
207 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
208 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
209 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
210 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
211 </ol>
212 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]213 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
214 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]215 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
216 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
217 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
218 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
219 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]220 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]221 </ol>
222 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]223 <li><a href="#int_debugger">Debugger intrinsics</a></li>
224 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]225 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]226 <ol>
227 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]228 </ol>
229 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]230 <li><a href="#int_atomics">Atomic intrinsics</a>
231 <ol>
232 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
233 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
234 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
235 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
236 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
237 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
238 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
239 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
240 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
241 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
242 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
243 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
244 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
245 </ol>
246 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]247 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]248 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]249 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]250 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]251 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]252 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]253 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]254 '<tt>llvm.trap</tt>' Intrinsic</a></li>
255 <li><a href="#int_stackprotector">
256 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]257 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]258 </li>
259 </ol>
260 </li>
261</ol>
262
263<div class="doc_author">
264 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
265 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
266</div>
267
268<!-- *********************************************************************** -->
269<div class="doc_section"> <a name="abstract">Abstract </a></div>
270<!-- *********************************************************************** -->
271
272<div class="doc_text">
273<p>This document is a reference manual for the LLVM assembly language.
Bill Wendlinge7846a52008-08-05 22:29:16 +0000[diff] [blame]274LLVM is a Static Single Assignment (SSA) based representation that provides
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]275type safety, low-level operations, flexibility, and the capability of
276representing 'all' high-level languages cleanly. It is the common code
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]277representation used throughout all phases of the LLVM compilation
278strategy.</p>
279</div>
280
281<!-- *********************************************************************** -->
282<div class="doc_section"> <a name="introduction">Introduction</a> </div>
283<!-- *********************************************************************** -->
284
285<div class="doc_text">
286
287<p>The LLVM code representation is designed to be used in three
288different forms: as an in-memory compiler IR, as an on-disk bitcode
289representation (suitable for fast loading by a Just-In-Time compiler),
290and as a human readable assembly language representation. This allows
291LLVM to provide a powerful intermediate representation for efficient
292compiler transformations and analysis, while providing a natural means
293to debug and visualize the transformations. The three different forms
294of LLVM are all equivalent. This document describes the human readable
295representation and notation.</p>
296
297<p>The LLVM representation aims to be light-weight and low-level
298while being expressive, typed, and extensible at the same time. It
299aims to be a "universal IR" of sorts, by being at a low enough level
300that high-level ideas may be cleanly mapped to it (similar to how
301microprocessors are "universal IR's", allowing many source languages to
302be mapped to them). By providing type information, LLVM can be used as
303the target of optimizations: for example, through pointer analysis, it
304can be proven that a C automatic variable is never accessed outside of
305the current function... allowing it to be promoted to a simple SSA
306value instead of a memory location.</p>
307
308</div>
309
310<!-- _______________________________________________________________________ -->
311<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
312
313<div class="doc_text">
314
315<p>It is important to note that this document describes 'well formed'
316LLVM assembly language. There is a difference between what the parser
317accepts and what is considered 'well formed'. For example, the
318following instruction is syntactically okay, but not well formed:</p>
319
320<div class="doc_code">
321<pre>
322%x = <a href="#i_add">add</a> i32 1, %x
323</pre>
324</div>
325
326<p>...because the definition of <tt>%x</tt> does not dominate all of
327its uses. The LLVM infrastructure provides a verification pass that may
328be used to verify that an LLVM module is well formed. This pass is
329automatically run by the parser after parsing input assembly and by
330the optimizer before it outputs bitcode. The violations pointed out
331by the verifier pass indicate bugs in transformation passes or input to
332the parser.</p>
333</div>
334
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]335<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]336
337<!-- *********************************************************************** -->
338<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
339<!-- *********************************************************************** -->
340
341<div class="doc_text">
342
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]343 <p>LLVM identifiers come in two basic types: global and local. Global
344 identifiers (functions, global variables) begin with the @ character. Local
345 identifiers (register names, types) begin with the % character. Additionally,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]346 there are three different formats for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]347
348<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]349 <li>Named values are represented as a string of characters with their prefix.
350 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
351 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]352 Identifiers which require other characters in their names can be surrounded
Daniel Dunbar73f9a772008-10-14 23:51:43 +0000[diff] [blame]353 with quotes. Special characters may be escaped using "\xx" where xx is the
354 ASCII code for the character in hexadecimal. In this way, any character can
355 be used in a name value, even quotes themselves.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]356
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]357 <li>Unnamed values are represented as an unsigned numeric value with their
358 prefix. For example, %12, @2, %44.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]359
360 <li>Constants, which are described in a <a href="#constants">section about
361 constants</a>, below.</li>
362</ol>
363
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]364<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]365don't need to worry about name clashes with reserved words, and the set of
366reserved words may be expanded in the future without penalty. Additionally,
367unnamed identifiers allow a compiler to quickly come up with a temporary
368variable without having to avoid symbol table conflicts.</p>
369
370<p>Reserved words in LLVM are very similar to reserved words in other
371languages. There are keywords for different opcodes
372('<tt><a href="#i_add">add</a></tt>',
373 '<tt><a href="#i_bitcast">bitcast</a></tt>',
374 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
375href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
376and others. These reserved words cannot conflict with variable names, because
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]377none of them start with a prefix character ('%' or '@').</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]378
379<p>Here is an example of LLVM code to multiply the integer variable
380'<tt>%X</tt>' by 8:</p>
381
382<p>The easy way:</p>
383
384<div class="doc_code">
385<pre>
386%result = <a href="#i_mul">mul</a> i32 %X, 8
387</pre>
388</div>
389
390<p>After strength reduction:</p>
391
392<div class="doc_code">
393<pre>
394%result = <a href="#i_shl">shl</a> i32 %X, i8 3
395</pre>
396</div>
397
398<p>And the hard way:</p>
399
400<div class="doc_code">
401<pre>
402<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
403<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
404%result = <a href="#i_add">add</a> i32 %1, %1
405</pre>
406</div>
407
408<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
409important lexical features of LLVM:</p>
410
411<ol>
412
413 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
414 line.</li>
415
416 <li>Unnamed temporaries are created when the result of a computation is not
417 assigned to a named value.</li>
418
419 <li>Unnamed temporaries are numbered sequentially</li>
420
421</ol>
422
423<p>...and it also shows a convention that we follow in this document. When
424demonstrating instructions, we will follow an instruction with a comment that
425defines the type and name of value produced. Comments are shown in italic
426text.</p>
427
428</div>
429
430<!-- *********************************************************************** -->
431<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
432<!-- *********************************************************************** -->
433
434<!-- ======================================================================= -->
435<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
436</div>
437
438<div class="doc_text">
439
440<p>LLVM programs are composed of "Module"s, each of which is a
441translation unit of the input programs. Each module consists of
442functions, global variables, and symbol table entries. Modules may be
443combined together with the LLVM linker, which merges function (and
444global variable) definitions, resolves forward declarations, and merges
445symbol table entries. Here is an example of the "hello world" module:</p>
446
447<div class="doc_code">
448<pre><i>; Declare the string constant as a global constant...</i>
449<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
450 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
451
452<i>; External declaration of the puts function</i>
453<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
454
455<i>; Definition of main function</i>
456define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]457 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]458 %cast210 = <a
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]459 href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]460
461 <i>; Call puts function to write out the string to stdout...</i>
462 <a
463 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
464 <a
465 href="#i_ret">ret</a> i32 0<br>}<br>
466</pre>
467</div>
468
469<p>This example is made up of a <a href="#globalvars">global variable</a>
470named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
471function, and a <a href="#functionstructure">function definition</a>
472for "<tt>main</tt>".</p>
473
474<p>In general, a module is made up of a list of global values,
475where both functions and global variables are global values. Global values are
476represented by a pointer to a memory location (in this case, a pointer to an
477array of char, and a pointer to a function), and have one of the following <a
478href="#linkage">linkage types</a>.</p>
479
480</div>
481
482<!-- ======================================================================= -->
483<div class="doc_subsection">
484 <a name="linkage">Linkage Types</a>
485</div>
486
487<div class="doc_text">
488
489<p>
490All Global Variables and Functions have one of the following types of linkage:
491</p>
492
493<dl>
494
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]495 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
496
497 <dd>Global values with private linkage are only directly accessible by
498 objects in the current module. In particular, linking code into a module with
499 an private global value may cause the private to be renamed as necessary to
500 avoid collisions. Because the symbol is private to the module, all
501 references can be updated. This doesn't show up in any symbol table in the
502 object file.
503 </dd>
504
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]505 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]506
Duncan Sandsa75223a2009-01-16 09:29:46 +0000[diff] [blame]507 <dd> Similar to private, but the value shows as a local symbol (STB_LOCAL in
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]508 the case of ELF) in the object file. This corresponds to the notion of the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]509 '<tt>static</tt>' keyword in C.
510 </dd>
511
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]512 <dt><tt><b><a name="available_externally">available_externally</a></b></tt>:
513 </dt>
514
515 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
516 into the object file corresponding to the LLVM module. They exist to
517 allow inlining and other optimizations to take place given knowledge of the
518 definition of the global, which is known to be somewhere outside the module.
519 Globals with <tt>available_externally</tt> linkage are allowed to be discarded
520 at will, and are otherwise the same as <tt>linkonce_odr</tt>. This linkage
521 type is only allowed on definitions, not declarations.</dd>
522
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]523 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
524
525 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
526 the same name when linkage occurs. This is typically used to implement
527 inline functions, templates, or other code which must be generated in each
528 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
529 allowed to be discarded.
530 </dd>
531
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]532 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
533
534 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
535 linkage, except that unreferenced <tt>common</tt> globals may not be
536 discarded. This is used for globals that may be emitted in multiple
537 translation units, but that are not guaranteed to be emitted into every
538 translation unit that uses them. One example of this is tentative
539 definitions in C, such as "<tt>int X;</tt>" at global scope.
540 </dd>
541
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]542 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
543
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]544 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
545 that some targets may choose to emit different assembly sequences for them
546 for target-dependent reasons. This is used for globals that are declared
547 "weak" in C source code.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]548 </dd>
549
550 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
551
552 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
553 pointer to array type. When two global variables with appending linkage are
554 linked together, the two global arrays are appended together. This is the
555 LLVM, typesafe, equivalent of having the system linker append together
556 "sections" with identical names when .o files are linked.
557 </dd>
558
559 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]560
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]561 <dd>The semantics of this linkage follow the ELF object file model: the
562 symbol is weak until linked, if not linked, the symbol becomes null instead
563 of being an undefined reference.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]564 </dd>
565
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]566 <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]567 <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]568 <dd>Some languages allow differing globals to be merged, such as two
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]569 functions with different semantics. Other languages, such as <tt>C++</tt>,
570 ensure that only equivalent globals are ever merged (the "one definition
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]571 rule" - "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Duncan Sandsb95df792009-03-11 20:14:15 +0000[diff] [blame]572 and <tt>weak_odr</tt> linkage types to indicate that the global will only
573 be merged with equivalent globals. These linkage types are otherwise the
574 same as their non-<tt>odr</tt> versions.
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]575 </dd>
576
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]577 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
578
579 <dd>If none of the above identifiers are used, the global is externally
580 visible, meaning that it participates in linkage and can be used to resolve
581 external symbol references.
582 </dd>
583</dl>
584
585 <p>
586 The next two types of linkage are targeted for Microsoft Windows platform
587 only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]588 DLLs (Dynamic Link Libraries).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]589 </p>
590
591 <dl>
592 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
593
594 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
595 or variable via a global pointer to a pointer that is set up by the DLL
596 exporting the symbol. On Microsoft Windows targets, the pointer name is
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]597 formed by combining <code>__imp_</code> and the function or variable name.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]598 </dd>
599
600 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
601
602 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
603 pointer to a pointer in a DLL, so that it can be referenced with the
604 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]605 name is formed by combining <code>__imp_</code> and the function or variable
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]606 name.
607 </dd>
608
609</dl>
610
Dan Gohman4dfac702008-11-24 17:18:39 +0000[diff] [blame]611<p>For example, since the "<tt>.LC0</tt>"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]612variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
613variable and was linked with this one, one of the two would be renamed,
614preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
615external (i.e., lacking any linkage declarations), they are accessible
616outside of the current module.</p>
617<p>It is illegal for a function <i>declaration</i>
Duncan Sands565f65d2009-03-11 08:08:06 +0000[diff] [blame]618to have any linkage type other than "externally visible", <tt>dllimport</tt>
619or <tt>extern_weak</tt>.</p>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]620<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
621or <tt>weak_odr</tt> linkages.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]622</div>
623
624<!-- ======================================================================= -->
625<div class="doc_subsection">
626 <a name="callingconv">Calling Conventions</a>
627</div>
628
629<div class="doc_text">
630
631<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
632and <a href="#i_invoke">invokes</a> can all have an optional calling convention
633specified for the call. The calling convention of any pair of dynamic
634caller/callee must match, or the behavior of the program is undefined. The
635following calling conventions are supported by LLVM, and more may be added in
636the future:</p>
637
638<dl>
639 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
640
641 <dd>This calling convention (the default if no other calling convention is
642 specified) matches the target C calling conventions. This calling convention
643 supports varargs function calls and tolerates some mismatch in the declared
644 prototype and implemented declaration of the function (as does normal C).
645 </dd>
646
647 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
648
649 <dd>This calling convention attempts to make calls as fast as possible
650 (e.g. by passing things in registers). This calling convention allows the
651 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]652 without having to conform to an externally specified ABI (Application Binary
653 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]654 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
655 supported. This calling convention does not support varargs and requires the
656 prototype of all callees to exactly match the prototype of the function
657 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]658 </dd>
659
660 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
661
662 <dd>This calling convention attempts to make code in the caller as efficient
663 as possible under the assumption that the call is not commonly executed. As
664 such, these calls often preserve all registers so that the call does not break
665 any live ranges in the caller side. This calling convention does not support
666 varargs and requires the prototype of all callees to exactly match the
667 prototype of the function definition.
668 </dd>
669
670 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
671
672 <dd>Any calling convention may be specified by number, allowing
673 target-specific calling conventions to be used. Target specific calling
674 conventions start at 64.
675 </dd>
676</dl>
677
678<p>More calling conventions can be added/defined on an as-needed basis, to
679support pascal conventions or any other well-known target-independent
680convention.</p>
681
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
691<p>
692All Global Variables and Functions have one of the following visibility styles:
693</p>
694
695<dl>
696 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
697
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]698 <dd>On targets that use the ELF object file format, default visibility means
699 that the declaration is visible to other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]700 modules and, in shared libraries, means that the declared entity may be
701 overridden. On Darwin, default visibility means that the declaration is
702 visible to other modules. Default visibility corresponds to "external
703 linkage" in the language.
704 </dd>
705
706 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
707
708 <dd>Two declarations of an object with hidden visibility refer to the same
709 object if they are in the same shared object. Usually, hidden visibility
710 indicates that the symbol will not be placed into the dynamic symbol table,
711 so no other module (executable or shared library) can reference it
712 directly.
713 </dd>
714
715 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
716
717 <dd>On ELF, protected visibility indicates that the symbol will be placed in
718 the dynamic symbol table, but that references within the defining module will
719 bind to the local symbol. That is, the symbol cannot be overridden by another
720 module.
721 </dd>
722</dl>
723
724</div>
725
726<!-- ======================================================================= -->
727<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]728 <a name="namedtypes">Named Types</a>
729</div>
730
731<div class="doc_text">
732
733<p>LLVM IR allows you to specify name aliases for certain types. This can make
734it easier to read the IR and make the IR more condensed (particularly when
735recursive types are involved). An example of a name specification is:
736</p>
737
738<div class="doc_code">
739<pre>
740%mytype = type { %mytype*, i32 }
741</pre>
742</div>
743
744<p>You may give a name to any <a href="#typesystem">type</a> except "<a
745href="t_void">void</a>". Type name aliases may be used anywhere a type is
746expected with the syntax "%mytype".</p>
747
748<p>Note that type names are aliases for the structural type that they indicate,
749and that you can therefore specify multiple names for the same type. This often
750leads to confusing behavior when dumping out a .ll file. Since LLVM IR uses
751structural typing, the name is not part of the type. When printing out LLVM IR,
752the printer will pick <em>one name</em> to render all types of a particular
753shape. This means that if you have code where two different source types end up
754having the same LLVM type, that the dumper will sometimes print the "wrong" or
755unexpected type. This is an important design point and isn't going to
756change.</p>
757
758</div>
759
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]760<!-- ======================================================================= -->
761<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]762 <a name="globalvars">Global Variables</a>
763</div>
764
765<div class="doc_text">
766
767<p>Global variables define regions of memory allocated at compilation time
768instead of run-time. Global variables may optionally be initialized, may have
769an explicit section to be placed in, and may have an optional explicit alignment
770specified. A variable may be defined as "thread_local", which means that it
771will not be shared by threads (each thread will have a separated copy of the
772variable). A variable may be defined as a global "constant," which indicates
773that the contents of the variable will <b>never</b> be modified (enabling better
774optimization, allowing the global data to be placed in the read-only section of
775an executable, etc). Note that variables that need runtime initialization
776cannot be marked "constant" as there is a store to the variable.</p>
777
778<p>
779LLVM explicitly allows <em>declarations</em> of global variables to be marked
780constant, even if the final definition of the global is not. This capability
781can be used to enable slightly better optimization of the program, but requires
782the language definition to guarantee that optimizations based on the
783'constantness' are valid for the translation units that do not include the
784definition.
785</p>
786
787<p>As SSA values, global variables define pointer values that are in
788scope (i.e. they dominate) all basic blocks in the program. Global
789variables always define a pointer to their "content" type because they
790describe a region of memory, and all memory objects in LLVM are
791accessed through pointers.</p>
792
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]793<p>A global variable may be declared to reside in a target-specifc numbered
794address space. For targets that support them, address spaces may affect how
795optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]796the variable. The default address space is zero. The address space qualifier
797must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]798
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]799<p>LLVM allows an explicit section to be specified for globals. If the target
800supports it, it will emit globals to the section specified.</p>
801
802<p>An explicit alignment may be specified for a global. If not present, or if
803the alignment is set to zero, the alignment of the global is set by the target
804to whatever it feels convenient. If an explicit alignment is specified, the
805global is forced to have at least that much alignment. All alignments must be
806a power of 2.</p>
807
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]808<p>For example, the following defines a global in a numbered address space with
809an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]810
811<div class="doc_code">
812<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]813@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]814</pre>
815</div>
816
817</div>
818
819
820<!-- ======================================================================= -->
821<div class="doc_subsection">
822 <a name="functionstructure">Functions</a>
823</div>
824
825<div class="doc_text">
826
827<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
828an optional <a href="#linkage">linkage type</a>, an optional
829<a href="#visibility">visibility style</a>, an optional
830<a href="#callingconv">calling convention</a>, a return type, an optional
831<a href="#paramattrs">parameter attribute</a> for the return type, a function
832name, a (possibly empty) argument list (each with optional
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]833<a href="#paramattrs">parameter attributes</a>), optional
834<a href="#fnattrs">function attributes</a>, an optional section,
835an optional alignment, an optional <a href="#gc">garbage collector name</a>,
Chris Lattneree202542008-10-04 18:10:21 +0000[diff] [blame]836an opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]837
838LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
839optional <a href="#linkage">linkage type</a>, an optional
840<a href="#visibility">visibility style</a>, an optional
841<a href="#callingconv">calling convention</a>, a return type, an optional
842<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]843name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]844<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]845
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]846<p>A function definition contains a list of basic blocks, forming the CFG
847(Control Flow Graph) for
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]848the function. Each basic block may optionally start with a label (giving the
849basic block a symbol table entry), contains a list of instructions, and ends
850with a <a href="#terminators">terminator</a> instruction (such as a branch or
851function return).</p>
852
853<p>The first basic block in a function is special in two ways: it is immediately
854executed on entrance to the function, and it is not allowed to have predecessor
855basic blocks (i.e. there can not be any branches to the entry block of a
856function). Because the block can have no predecessors, it also cannot have any
857<a href="#i_phi">PHI nodes</a>.</p>
858
859<p>LLVM allows an explicit section to be specified for functions. If the target
860supports it, it will emit functions to the section specified.</p>
861
862<p>An explicit alignment may be specified for a function. If not present, or if
863the alignment is set to zero, the alignment of the function is set by the target
864to whatever it feels convenient. If an explicit alignment is specified, the
865function is forced to have at least that much alignment. All alignments must be
866a power of 2.</p>
867
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]868 <h5>Syntax:</h5>
869
870<div class="doc_code">
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]871<tt>
872define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
873 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
874 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
875 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
876 [<a href="#gc">gc</a>] { ... }
877</tt>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]878</div>
879
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]880</div>
881
882
883<!-- ======================================================================= -->
884<div class="doc_subsection">
885 <a name="aliasstructure">Aliases</a>
886</div>
887<div class="doc_text">
888 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]889 function, global variable, another alias or bitcast of global value). Aliases
890 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]891 optional <a href="#visibility">visibility style</a>.</p>
892
893 <h5>Syntax:</h5>
894
895<div class="doc_code">
896<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]897@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]898</pre>
899</div>
900
901</div>
902
903
904
905<!-- ======================================================================= -->
906<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
907<div class="doc_text">
908 <p>The return type and each parameter of a function type may have a set of
909 <i>parameter attributes</i> associated with them. Parameter attributes are
910 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]911 a function. Parameter attributes are considered to be part of the function,
912 not of the function type, so functions with different parameter attributes
913 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]914
915 <p>Parameter attributes are simple keywords that follow the type specified. If
916 multiple parameter attributes are needed, they are space separated. For
917 example:</p>
918
919<div class="doc_code">
920<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]921declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]922declare i32 @atoi(i8 zeroext)
923declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]924</pre>
925</div>
926
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]927 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
928 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]929
930 <p>Currently, only the following parameter attributes are defined:</p>
931 <dl>
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]932 <dt><tt>zeroext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]933 <dd>This indicates to the code generator that the parameter or return value
934 should be zero-extended to a 32-bit value by the caller (for a parameter)
935 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]936
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]937 <dt><tt>signext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]938 <dd>This indicates to the code generator that the parameter or return value
939 should be sign-extended to a 32-bit value by the caller (for a parameter)
940 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]941
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]942 <dt><tt>inreg</tt></dt>
Dale Johannesenc08a0e22008-09-25 20:47:45 +0000[diff] [blame]943 <dd>This indicates that this parameter or return value should be treated
944 in a special target-dependent fashion during while emitting code for a
945 function call or return (usually, by putting it in a register as opposed
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]946 to memory, though some targets use it to distinguish between two different
947 kinds of registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]948
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]949 <dt><tt><a name="byval">byval</a></tt></dt>
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]950 <dd>This indicates that the pointer parameter should really be passed by
951 value to the function. The attribute implies that a hidden copy of the
952 pointee is made between the caller and the callee, so the callee is unable
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]953 to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]954 pointer arguments. It is generally used to pass structs and arrays by
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]955 value, but is also valid on pointers to scalars. The copy is considered to
956 belong to the caller not the callee (for example,
957 <tt><a href="#readonly">readonly</a></tt> functions should not write to
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]958 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnere39c5bf2009-02-05 05:42:28 +0000[diff] [blame]959 values. The byval attribute also supports specifying an alignment with the
960 align attribute. This has a target-specific effect on the code generator
961 that usually indicates a desired alignment for the synthesized stack
962 slot.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]963
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]964 <dt><tt>sret</tt></dt>
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]965 <dd>This indicates that the pointer parameter specifies the address of a
966 structure that is the return value of the function in the source program.
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]967 This pointer must be guaranteed by the caller to be valid: loads and stores
968 to the structure may be assumed by the callee to not to trap. This may only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]969 be applied to the first parameter. This is not a valid attribute for
970 return values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]971
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]972 <dt><tt>noalias</tt></dt>
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]973 <dd>This indicates that the pointer does not alias any global or any other
974 parameter. The caller is responsible for ensuring that this is the
Nick Lewyckya604a942008-11-24 05:00:44 +0000[diff] [blame]975 case. On a function return value, <tt>noalias</tt> additionally indicates
976 that the pointer does not alias any other pointers visible to the
Nick Lewycky40fb6f22008-12-19 06:39:12 +0000[diff] [blame]977 caller. For further details, please see the discussion of the NoAlias
978 response in
979 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
980 analysis</a>.</dd>
981
982 <dt><tt>nocapture</tt></dt>
983 <dd>This indicates that the callee does not make any copies of the pointer
984 that outlive the callee itself. This is not a valid attribute for return
985 values.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]986
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]987 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]988 <dd>This indicates that the pointer parameter can be excised using the
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]989 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
990 attribute for return values.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]991 </dl>
992
993</div>
994
995<!-- ======================================================================= -->
996<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]997 <a name="gc">Garbage Collector Names</a>
998</div>
999
1000<div class="doc_text">
1001<p>Each function may specify a garbage collector name, which is simply a
1002string.</p>
1003
1004<div class="doc_code"><pre
1005>define void @f() gc "name" { ...</pre></div>
1006
1007<p>The compiler declares the supported values of <i>name</i>. Specifying a
1008collector which will cause the compiler to alter its output in order to support
1009the named garbage collection algorithm.</p>
1010</div>
1011
1012<!-- ======================================================================= -->
1013<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1014 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1015</div>
1016
1017<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1018
1019<p>Function attributes are set to communicate additional information about
1020 a function. Function attributes are considered to be part of the function,
1021 not of the function type, so functions with different parameter attributes
1022 can have the same function type.</p>
1023
1024 <p>Function attributes are simple keywords that follow the type specified. If
1025 multiple attributes are needed, they are space separated. For
1026 example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1027
1028<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1029<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1030define void @f() noinline { ... }
1031define void @f() alwaysinline { ... }
1032define void @f() alwaysinline optsize { ... }
1033define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1034</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1035</div>
1036
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1037<dl>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1038<dt><tt>alwaysinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1039<dd>This attribute indicates that the inliner should attempt to inline this
1040function into callers whenever possible, ignoring any active inlining size
1041threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1042
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1043<dt><tt>noinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1044<dd>This attribute indicates that the inliner should never inline this function
Chris Lattner377f3ae2008-10-05 17:14:59 +0000[diff] [blame]1045in any situation. This attribute may not be used together with the
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1046<tt>alwaysinline</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1047
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1048<dt><tt>optsize</tt></dt>
Devang Patelc29099b2008-09-29 18:34:44 +0000[diff] [blame]1049<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1050make choices that keep the code size of this function low, and otherwise do
1051optimizations specifically to reduce code size.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1052
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1053<dt><tt>noreturn</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1054<dd>This function attribute indicates that the function never returns normally.
1055This produces undefined behavior at runtime if the function ever does
1056dynamically return.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1057
1058<dt><tt>nounwind</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1059<dd>This function attribute indicates that the function never returns with an
1060unwind or exceptional control flow. If the function does unwind, its runtime
1061behavior is undefined.</dd>
1062
1063<dt><tt>readnone</tt></dt>
Duncan Sands2f500832009-05-06 06:49:50 +0000[diff] [blame]1064<dd>This attribute indicates that the function computes its result (or decides to
1065unwind an exception) based strictly on its arguments, without dereferencing any
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1066pointer arguments or otherwise accessing any mutable state (e.g. memory, control
1067registers, etc) visible to caller functions. It does not write through any
1068pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
Duncan Sands2f500832009-05-06 06:49:50 +0000[diff] [blame]1069never changes any state visible to callers. This means that it cannot unwind
1070exceptions by calling the <tt>C++</tt> exception throwing methods, but could
1071use the <tt>unwind</tt> instruction.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1072
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1073<dt><tt><a name="readonly">readonly</a></tt></dt>
1074<dd>This attribute indicates that the function does not write through any
1075pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
1076or otherwise modify any state (e.g. memory, control registers, etc) visible to
1077caller functions. It may dereference pointer arguments and read state that may
Duncan Sands2f500832009-05-06 06:49:50 +0000[diff] [blame]1078be set in the caller. A readonly function always returns the same value (or
1079unwinds an exception identically) when called with the same set of arguments
1080and global state. It cannot unwind an exception by calling the <tt>C++</tt>
1081exception throwing methods, but may use the <tt>unwind</tt> instruction.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1082
1083<dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1084<dd>This attribute indicates that the function should emit a stack smashing
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1085protector. It is in the form of a "canary"&mdash;a random value placed on the
1086stack before the local variables that's checked upon return from the function to
1087see if it has been overwritten. A heuristic is used to determine if a function
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1088needs stack protectors or not.
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1089
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1090<p>If a function that has an <tt>ssp</tt> attribute is inlined into a function
1091that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
1092have an <tt>ssp</tt> attribute.</p></dd>
1093
1094<dt><tt>sspreq</tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1095<dd>This attribute indicates that the function should <em>always</em> emit a
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1096stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1097function attribute.
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1098
1099<p>If a function that has an <tt>sspreq</tt> attribute is inlined into a
1100function that doesn't have an <tt>sspreq</tt> attribute or which has
1101an <tt>ssp</tt> attribute, then the resulting function will have
1102an <tt>sspreq</tt> attribute.</p></dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1103</dl>
1104
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1105</div>
1106
1107<!-- ======================================================================= -->
1108<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1109 <a name="moduleasm">Module-Level Inline Assembly</a>
1110</div>
1111
1112<div class="doc_text">
1113<p>
1114Modules may contain "module-level inline asm" blocks, which corresponds to the
1115GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1116LLVM and treated as a single unit, but may be separated in the .ll file if
1117desired. The syntax is very simple:
1118</p>
1119
1120<div class="doc_code">
1121<pre>
1122module asm "inline asm code goes here"
1123module asm "more can go here"
1124</pre>
1125</div>
1126
1127<p>The strings can contain any character by escaping non-printable characters.
1128 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1129 for the number.
1130</p>
1131
1132<p>
1133 The inline asm code is simply printed to the machine code .s file when
1134 assembly code is generated.
1135</p>
1136</div>
1137
1138<!-- ======================================================================= -->
1139<div class="doc_subsection">
1140 <a name="datalayout">Data Layout</a>
1141</div>
1142
1143<div class="doc_text">
1144<p>A module may specify a target specific data layout string that specifies how
1145data is to be laid out in memory. The syntax for the data layout is simply:</p>
1146<pre> target datalayout = "<i>layout specification</i>"</pre>
1147<p>The <i>layout specification</i> consists of a list of specifications
1148separated by the minus sign character ('-'). Each specification starts with a
1149letter and may include other information after the letter to define some
1150aspect of the data layout. The specifications accepted are as follows: </p>
1151<dl>
1152 <dt><tt>E</tt></dt>
1153 <dd>Specifies that the target lays out data in big-endian form. That is, the
1154 bits with the most significance have the lowest address location.</dd>
1155 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1156 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1157 the bits with the least significance have the lowest address location.</dd>
1158 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1159 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1160 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1161 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1162 too.</dd>
1163 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1164 <dd>This specifies the alignment for an integer type of a given bit
1165 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1166 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1167 <dd>This specifies the alignment for a vector type of a given bit
1168 <i>size</i>.</dd>
1169 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1170 <dd>This specifies the alignment for a floating point type of a given bit
1171 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1172 (double).</dd>
1173 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1174 <dd>This specifies the alignment for an aggregate type of a given bit
1175 <i>size</i>.</dd>
1176</dl>
1177<p>When constructing the data layout for a given target, LLVM starts with a
1178default set of specifications which are then (possibly) overriden by the
1179specifications in the <tt>datalayout</tt> keyword. The default specifications
1180are given in this list:</p>
1181<ul>
1182 <li><tt>E</tt> - big endian</li>
1183 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1184 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1185 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1186 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1187 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1188 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1189 alignment of 64-bits</li>
1190 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1191 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1192 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1193 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1194 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
1195</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1196<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1197following rules:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1198<ol>
1199 <li>If the type sought is an exact match for one of the specifications, that
1200 specification is used.</li>
1201 <li>If no match is found, and the type sought is an integer type, then the
1202 smallest integer type that is larger than the bitwidth of the sought type is
1203 used. If none of the specifications are larger than the bitwidth then the the
1204 largest integer type is used. For example, given the default specifications
1205 above, the i7 type will use the alignment of i8 (next largest) while both
1206 i65 and i256 will use the alignment of i64 (largest specified).</li>
1207 <li>If no match is found, and the type sought is a vector type, then the
1208 largest vector type that is smaller than the sought vector type will be used
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1209 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1210 in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1211</ol>
1212</div>
1213
1214<!-- *********************************************************************** -->
1215<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1216<!-- *********************************************************************** -->
1217
1218<div class="doc_text">
1219
1220<p>The LLVM type system is one of the most important features of the
1221intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1222optimizations to be performed on the intermediate representation directly,
1223without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1224extra analyses on the side before the transformation. A strong type
1225system makes it easier to read the generated code and enables novel
1226analyses and transformations that are not feasible to perform on normal
1227three address code representations.</p>
1228
1229</div>
1230
1231<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1232<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1233Classifications</a> </div>
1234<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1235<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1236classifications:</p>
1237
1238<table border="1" cellspacing="0" cellpadding="4">
1239 <tbody>
1240 <tr><th>Classification</th><th>Types</th></tr>
1241 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1242 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1243 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1244 </tr>
1245 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1246 <td><a href="#t_floating">floating point</a></td>
1247 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1248 </tr>
1249 <tr>
1250 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1251 <td><a href="#t_integer">integer</a>,
1252 <a href="#t_floating">floating point</a>,
1253 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1254 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1255 <a href="#t_struct">structure</a>,
1256 <a href="#t_array">array</a>,
Dan Gohmand13951e2008-05-23 22:50:26 +0000[diff] [blame]1257 <a href="#t_label">label</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1258 </td>
1259 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1260 <tr>
1261 <td><a href="#t_primitive">primitive</a></td>
1262 <td><a href="#t_label">label</a>,
1263 <a href="#t_void">void</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1264 <a href="#t_floating">floating point</a>.</td>
1265 </tr>
1266 <tr>
1267 <td><a href="#t_derived">derived</a></td>
1268 <td><a href="#t_integer">integer</a>,
1269 <a href="#t_array">array</a>,
1270 <a href="#t_function">function</a>,
1271 <a href="#t_pointer">pointer</a>,
1272 <a href="#t_struct">structure</a>,
1273 <a href="#t_pstruct">packed structure</a>,
1274 <a href="#t_vector">vector</a>,
1275 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1276 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1277 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1278 </tbody>
1279</table>
1280
1281<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1282most important. Values of these types are the only ones which can be
1283produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1284instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1285</div>
1286
1287<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1288<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1289
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1290<div class="doc_text">
1291<p>The primitive types are the fundamental building blocks of the LLVM
1292system.</p>
1293
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1294</div>
1295
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1296<!-- _______________________________________________________________________ -->
1297<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1298
1299<div class="doc_text">
1300 <table>
1301 <tbody>
1302 <tr><th>Type</th><th>Description</th></tr>
1303 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1304 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1305 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1306 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1307 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1308 </tbody>
1309 </table>
1310</div>
1311
1312<!-- _______________________________________________________________________ -->
1313<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1314
1315<div class="doc_text">
1316<h5>Overview:</h5>
1317<p>The void type does not represent any value and has no size.</p>
1318
1319<h5>Syntax:</h5>
1320
1321<pre>
1322 void
1323</pre>
1324</div>
1325
1326<!-- _______________________________________________________________________ -->
1327<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1328
1329<div class="doc_text">
1330<h5>Overview:</h5>
1331<p>The label type represents code labels.</p>
1332
1333<h5>Syntax:</h5>
1334
1335<pre>
1336 label
1337</pre>
1338</div>
1339
1340
1341<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1342<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1343
1344<div class="doc_text">
1345
1346<p>The real power in LLVM comes from the derived types in the system.
1347This is what allows a programmer to represent arrays, functions,
1348pointers, and other useful types. Note that these derived types may be
1349recursive: For example, it is possible to have a two dimensional array.</p>
1350
1351</div>
1352
1353<!-- _______________________________________________________________________ -->
1354<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1355
1356<div class="doc_text">
1357
1358<h5>Overview:</h5>
1359<p>The integer type is a very simple derived type that simply specifies an
1360arbitrary bit width for the integer type desired. Any bit width from 1 bit to
13612^23-1 (about 8 million) can be specified.</p>
1362
1363<h5>Syntax:</h5>
1364
1365<pre>
1366 iN
1367</pre>
1368
1369<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1370value.</p>
1371
1372<h5>Examples:</h5>
1373<table class="layout">
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1374 <tbody>
1375 <tr>
1376 <td><tt>i1</tt></td>
1377 <td>a single-bit integer.</td>
1378 </tr><tr>
1379 <td><tt>i32</tt></td>
1380 <td>a 32-bit integer.</td>
1381 </tr><tr>
1382 <td><tt>i1942652</tt></td>
1383 <td>a really big integer of over 1 million bits.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1384 </tr>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1385 </tbody>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1386</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1387
1388<p>Note that the code generator does not yet support large integer types
1389to be used as function return types. The specific limit on how large a
1390return type the code generator can currently handle is target-dependent;
1391currently it's often 64 bits for 32-bit targets and 128 bits for 64-bit
1392targets.</p>
1393
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1394</div>
1395
1396<!-- _______________________________________________________________________ -->
1397<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1398
1399<div class="doc_text">
1400
1401<h5>Overview:</h5>
1402
1403<p>The array type is a very simple derived type that arranges elements
1404sequentially in memory. The array type requires a size (number of
1405elements) and an underlying data type.</p>
1406
1407<h5>Syntax:</h5>
1408
1409<pre>
1410 [&lt;# elements&gt; x &lt;elementtype&gt;]
1411</pre>
1412
1413<p>The number of elements is a constant integer value; elementtype may
1414be any type with a size.</p>
1415
1416<h5>Examples:</h5>
1417<table class="layout">
1418 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1419 <td class="left"><tt>[40 x i32]</tt></td>
1420 <td class="left">Array of 40 32-bit integer values.</td>
1421 </tr>
1422 <tr class="layout">
1423 <td class="left"><tt>[41 x i32]</tt></td>
1424 <td class="left">Array of 41 32-bit integer values.</td>
1425 </tr>
1426 <tr class="layout">
1427 <td class="left"><tt>[4 x i8]</tt></td>
1428 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1429 </tr>
1430</table>
1431<p>Here are some examples of multidimensional arrays:</p>
1432<table class="layout">
1433 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1434 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1435 <td class="left">3x4 array of 32-bit integer values.</td>
1436 </tr>
1437 <tr class="layout">
1438 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1439 <td class="left">12x10 array of single precision floating point values.</td>
1440 </tr>
1441 <tr class="layout">
1442 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1443 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1444 </tr>
1445</table>
1446
1447<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1448length array. Normally, accesses past the end of an array are undefined in
1449LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1450As a special case, however, zero length arrays are recognized to be variable
1451length. This allows implementation of 'pascal style arrays' with the LLVM
1452type "{ i32, [0 x float]}", for example.</p>
1453
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1454<p>Note that the code generator does not yet support large aggregate types
1455to be used as function return types. The specific limit on how large an
1456aggregate return type the code generator can currently handle is
1457target-dependent, and also dependent on the aggregate element types.</p>
1458
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1459</div>
1460
1461<!-- _______________________________________________________________________ -->
1462<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1463<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1464
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1465<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1466
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1467<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1468consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1469return type of a function type is a scalar type, a void type, or a struct type.
Devang Pateld5404c02008-03-24 20:52:42 +0000[diff] [blame]1470If the return type is a struct type then all struct elements must be of first
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1471class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1472
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1473<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1474
1475<pre>
1476 &lt;returntype list&gt; (&lt;parameter list&gt;)
1477</pre>
1478
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1479<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1480specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1481which indicates that the function takes a variable number of arguments.
1482Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1483 href="#int_varargs">variable argument handling intrinsic</a> functions.
1484'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1485<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1486
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1487<h5>Examples:</h5>
1488<table class="layout">
1489 <tr class="layout">
1490 <td class="left"><tt>i32 (i32)</tt></td>
1491 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1492 </td>
1493 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1494 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1495 </tt></td>
1496 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1497 an <tt>i16</tt> that should be sign extended and a
1498 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1499 <tt>float</tt>.
1500 </td>
1501 </tr><tr class="layout">
1502 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1503 <td class="left">A vararg function that takes at least one
1504 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1505 which returns an integer. This is the signature for <tt>printf</tt> in
1506 LLVM.
1507 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1508 </tr><tr class="layout">
1509 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1510 <td class="left">A function taking an <tt>i32</tt>, returning two
1511 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1512 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1513 </tr>
1514</table>
1515
1516</div>
1517<!-- _______________________________________________________________________ -->
1518<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1519<div class="doc_text">
1520<h5>Overview:</h5>
1521<p>The structure type is used to represent a collection of data members
1522together in memory. The packing of the field types is defined to match
1523the ABI of the underlying processor. The elements of a structure may
1524be any type that has a size.</p>
1525<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1526and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1527field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1528instruction.</p>
1529<h5>Syntax:</h5>
1530<pre> { &lt;type list&gt; }<br></pre>
1531<h5>Examples:</h5>
1532<table class="layout">
1533 <tr class="layout">
1534 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1535 <td class="left">A triple of three <tt>i32</tt> values</td>
1536 </tr><tr class="layout">
1537 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1538 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1539 second element is a <a href="#t_pointer">pointer</a> to a
1540 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1541 an <tt>i32</tt>.</td>
1542 </tr>
1543</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1544
1545<p>Note that the code generator does not yet support large aggregate types
1546to be used as function return types. The specific limit on how large an
1547aggregate return type the code generator can currently handle is
1548target-dependent, and also dependent on the aggregate element types.</p>
1549
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1550</div>
1551
1552<!-- _______________________________________________________________________ -->
1553<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1554</div>
1555<div class="doc_text">
1556<h5>Overview:</h5>
1557<p>The packed structure type is used to represent a collection of data members
1558together in memory. There is no padding between fields. Further, the alignment
1559of a packed structure is 1 byte. The elements of a packed structure may
1560be any type that has a size.</p>
1561<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1562and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1563field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1564instruction.</p>
1565<h5>Syntax:</h5>
1566<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1567<h5>Examples:</h5>
1568<table class="layout">
1569 <tr class="layout">
1570 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1571 <td class="left">A triple of three <tt>i32</tt> values</td>
1572 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1573 <td class="left">
1574<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1575 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1576 second element is a <a href="#t_pointer">pointer</a> to a
1577 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1578 an <tt>i32</tt>.</td>
1579 </tr>
1580</table>
1581</div>
1582
1583<!-- _______________________________________________________________________ -->
1584<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1585<div class="doc_text">
1586<h5>Overview:</h5>
1587<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1588reference to another object, which must live in memory. Pointer types may have
1589an optional address space attribute defining the target-specific numbered
1590address space where the pointed-to object resides. The default address space is
1591zero.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1592
1593<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does
Chris Lattner0d879e02009-02-08 22:21:28 +0000[diff] [blame]1594it permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1595
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1596<h5>Syntax:</h5>
1597<pre> &lt;type&gt; *<br></pre>
1598<h5>Examples:</h5>
1599<table class="layout">
1600 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1601 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1602 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1603 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1604 </tr>
1605 <tr class="layout">
1606 <td class="left"><tt>i32 (i32 *) *</tt></td>
1607 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1608 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1609 <tt>i32</tt>.</td>
1610 </tr>
1611 <tr class="layout">
1612 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1613 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1614 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1615 </tr>
1616</table>
1617</div>
1618
1619<!-- _______________________________________________________________________ -->
1620<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1621<div class="doc_text">
1622
1623<h5>Overview:</h5>
1624
1625<p>A vector type is a simple derived type that represents a vector
1626of elements. Vector types are used when multiple primitive data
1627are operated in parallel using a single instruction (SIMD).
1628A vector type requires a size (number of
1629elements) and an underlying primitive data type. Vectors must have a power
1630of two length (1, 2, 4, 8, 16 ...). Vector types are
1631considered <a href="#t_firstclass">first class</a>.</p>
1632
1633<h5>Syntax:</h5>
1634
1635<pre>
1636 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1637</pre>
1638
1639<p>The number of elements is a constant integer value; elementtype may
1640be any integer or floating point type.</p>
1641
1642<h5>Examples:</h5>
1643
1644<table class="layout">
1645 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1646 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1647 <td class="left">Vector of 4 32-bit integer values.</td>
1648 </tr>
1649 <tr class="layout">
1650 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1651 <td class="left">Vector of 8 32-bit floating-point values.</td>
1652 </tr>
1653 <tr class="layout">
1654 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1655 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1656 </tr>
1657</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1658
1659<p>Note that the code generator does not yet support large vector types
1660to be used as function return types. The specific limit on how large a
1661vector return type codegen can currently handle is target-dependent;
1662currently it's often a few times longer than a hardware vector register.</p>
1663
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1664</div>
1665
1666<!-- _______________________________________________________________________ -->
1667<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1668<div class="doc_text">
1669
1670<h5>Overview:</h5>
1671
1672<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1673corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1674In LLVM, opaque types can eventually be resolved to any type (not just a
1675structure type).</p>
1676
1677<h5>Syntax:</h5>
1678
1679<pre>
1680 opaque
1681</pre>
1682
1683<h5>Examples:</h5>
1684
1685<table class="layout">
1686 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1687 <td class="left"><tt>opaque</tt></td>
1688 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1689 </tr>
1690</table>
1691</div>
1692
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1693<!-- ======================================================================= -->
1694<div class="doc_subsection">
1695 <a name="t_uprefs">Type Up-references</a>
1696</div>
1697
1698<div class="doc_text">
1699<h5>Overview:</h5>
1700<p>
1701An "up reference" allows you to refer to a lexically enclosing type without
1702requiring it to have a name. For instance, a structure declaration may contain a
1703pointer to any of the types it is lexically a member of. Example of up
1704references (with their equivalent as named type declarations) include:</p>
1705
1706<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1707 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1708 { \2 }* %y = type { %y }*
1709 \1* %z = type %z*
1710</pre>
1711
1712<p>
1713An up reference is needed by the asmprinter for printing out cyclic types when
1714there is no declared name for a type in the cycle. Because the asmprinter does
1715not want to print out an infinite type string, it needs a syntax to handle
1716recursive types that have no names (all names are optional in llvm IR).
1717</p>
1718
1719<h5>Syntax:</h5>
1720<pre>
1721 \&lt;level&gt;
1722</pre>
1723
1724<p>
1725The level is the count of the lexical type that is being referred to.
1726</p>
1727
1728<h5>Examples:</h5>
1729
1730<table class="layout">
1731 <tr class="layout">
1732 <td class="left"><tt>\1*</tt></td>
1733 <td class="left">Self-referential pointer.</td>
1734 </tr>
1735 <tr class="layout">
1736 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1737 <td class="left">Recursive structure where the upref refers to the out-most
1738 structure.</td>
1739 </tr>
1740</table>
1741</div>
1742
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1743
1744<!-- *********************************************************************** -->
1745<div class="doc_section"> <a name="constants">Constants</a> </div>
1746<!-- *********************************************************************** -->
1747
1748<div class="doc_text">
1749
1750<p>LLVM has several different basic types of constants. This section describes
1751them all and their syntax.</p>
1752
1753</div>
1754
1755<!-- ======================================================================= -->
1756<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1757
1758<div class="doc_text">
1759
1760<dl>
1761 <dt><b>Boolean constants</b></dt>
1762
1763 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1764 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1765 </dd>
1766
1767 <dt><b>Integer constants</b></dt>
1768
1769 <dd>Standard integers (such as '4') are constants of the <a
1770 href="#t_integer">integer</a> type. Negative numbers may be used with
1771 integer types.
1772 </dd>
1773
1774 <dt><b>Floating point constants</b></dt>
1775
1776 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1777 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1778 notation (see below). The assembler requires the exact decimal value of
1779 a floating-point constant. For example, the assembler accepts 1.25 but
1780 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1781 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1782
1783 <dt><b>Null pointer constants</b></dt>
1784
1785 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1786 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1787
1788</dl>
1789
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1790<p>The one non-intuitive notation for constants is the hexadecimal form
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1791of floating point constants. For example, the form '<tt>double
17920x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
17934.5e+15</tt>'. The only time hexadecimal floating point constants are required
1794(and the only time that they are generated by the disassembler) is when a
1795floating point constant must be emitted but it cannot be represented as a
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1796decimal floating point number in a reasonable number of digits. For example,
1797NaN's, infinities, and other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1798special values are represented in their IEEE hexadecimal format so that
1799assembly and disassembly do not cause any bits to change in the constants.</p>
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1800<p>When using the hexadecimal form, constants of types float and double are
1801represented using the 16-digit form shown above (which matches the IEEE754
1802representation for double); float values must, however, be exactly representable
1803as IEE754 single precision.
1804Hexadecimal format is always used for long
1805double, and there are three forms of long double. The 80-bit
1806format used by x86 is represented as <tt>0xK</tt>
1807followed by 20 hexadecimal digits.
1808The 128-bit format used by PowerPC (two adjacent doubles) is represented
1809by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit
1810format is represented
1811by <tt>0xL</tt> followed by 32 hexadecimal digits; no currently supported
1812target uses this format. Long doubles will only work if they match
1813the long double format on your target. All hexadecimal formats are big-endian
1814(sign bit at the left).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1815</div>
1816
1817<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1818<div class="doc_subsection">
1819<a name="aggregateconstants"> <!-- old anchor -->
1820<a name="complexconstants">Complex Constants</a></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1821</div>
1822
1823<div class="doc_text">
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1824<p>Complex constants are a (potentially recursive) combination of simple
1825constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1826
1827<dl>
1828 <dt><b>Structure constants</b></dt>
1829
1830 <dd>Structure constants are represented with notation similar to structure
1831 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1832 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1833 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>". Structure constants
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1834 must have <a href="#t_struct">structure type</a>, and the number and
1835 types of elements must match those specified by the type.
1836 </dd>
1837
1838 <dt><b>Array constants</b></dt>
1839
1840 <dd>Array constants are represented with notation similar to array type
1841 definitions (a comma separated list of elements, surrounded by square brackets
1842 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1843 constants must have <a href="#t_array">array type</a>, and the number and
1844 types of elements must match those specified by the type.
1845 </dd>
1846
1847 <dt><b>Vector constants</b></dt>
1848
1849 <dd>Vector constants are represented with notation similar to vector type
1850 definitions (a comma separated list of elements, surrounded by
1851 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1852 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1853 href="#t_vector">vector type</a>, and the number and types of elements must
1854 match those specified by the type.
1855 </dd>
1856
1857 <dt><b>Zero initialization</b></dt>
1858
1859 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1860 value to zero of <em>any</em> type, including scalar and aggregate types.
1861 This is often used to avoid having to print large zero initializers (e.g. for
1862 large arrays) and is always exactly equivalent to using explicit zero
1863 initializers.
1864 </dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1865
1866 <dt><b>Metadata node</b></dt>
1867
1868 <dd>A metadata node is a structure-like constant with the type of an empty
1869 struct. For example: "<tt>{ } !{ i32 0, { } !"test" }</tt>". Unlike other
1870 constants that are meant to be interpreted as part of the instruction stream,
1871 metadata is a place to attach additional information such as debug info.
1872 </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1873</dl>
1874
1875</div>
1876
1877<!-- ======================================================================= -->
1878<div class="doc_subsection">
1879 <a name="globalconstants">Global Variable and Function Addresses</a>
1880</div>
1881
1882<div class="doc_text">
1883
1884<p>The addresses of <a href="#globalvars">global variables</a> and <a
1885href="#functionstructure">functions</a> are always implicitly valid (link-time)
1886constants. These constants are explicitly referenced when the <a
1887href="#identifiers">identifier for the global</a> is used and always have <a
1888href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1889file:</p>
1890
1891<div class="doc_code">
1892<pre>
1893@X = global i32 17
1894@Y = global i32 42
1895@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1896</pre>
1897</div>
1898
1899</div>
1900
1901<!-- ======================================================================= -->
1902<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1903<div class="doc_text">
1904 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1905 no specific value. Undefined values may be of any type and be used anywhere
1906 a constant is permitted.</p>
1907
1908 <p>Undefined values indicate to the compiler that the program is well defined
1909 no matter what value is used, giving the compiler more freedom to optimize.
1910 </p>
1911</div>
1912
1913<!-- ======================================================================= -->
1914<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1915</div>
1916
1917<div class="doc_text">
1918
1919<p>Constant expressions are used to allow expressions involving other constants
1920to be used as constants. Constant expressions may be of any <a
1921href="#t_firstclass">first class</a> type and may involve any LLVM operation
1922that does not have side effects (e.g. load and call are not supported). The
1923following is the syntax for constant expressions:</p>
1924
1925<dl>
1926 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1927 <dd>Truncate a constant to another type. The bit size of CST must be larger
1928 than the bit size of TYPE. Both types must be integers.</dd>
1929
1930 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1931 <dd>Zero extend a constant to another type. The bit size of CST must be
1932 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1933
1934 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1935 <dd>Sign extend a constant to another type. The bit size of CST must be
1936 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1937
1938 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1939 <dd>Truncate a floating point constant to another floating point type. The
1940 size of CST must be larger than the size of TYPE. Both types must be
1941 floating point.</dd>
1942
1943 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1944 <dd>Floating point extend a constant to another type. The size of CST must be
1945 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1946
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1947 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1948 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1949 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1950 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1951 of the same number of elements. If the value won't fit in the integer type,
1952 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1953
1954 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1955 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1956 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1957 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1958 of the same number of elements. If the value won't fit in the integer type,
1959 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1960
1961 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1962 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1963 constant. TYPE must be a scalar or vector floating point type. CST must be of
1964 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1965 of the same number of elements. If the value won't fit in the floating point
1966 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1967
1968 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
1969 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1970 constant. TYPE must be a scalar or vector floating point type. CST must be of
1971 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1972 of the same number of elements. If the value won't fit in the floating point
1973 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1974
1975 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1976 <dd>Convert a pointer typed constant to the corresponding integer constant
1977 TYPE must be an integer type. CST must be of pointer type. The CST value is
1978 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1979
1980 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1981 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1982 pointer type. CST must be of integer type. The CST value is zero extended,
1983 truncated, or unchanged to make it fit in a pointer size. This one is
1984 <i>really</i> dangerous!</dd>
1985
1986 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]1987 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
1988 are the same as those for the <a href="#i_bitcast">bitcast
1989 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1990
1991 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1992
1993 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1994 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1995 instruction, the index list may have zero or more indexes, which are required
1996 to make sense for the type of "CSTPTR".</dd>
1997
1998 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1999
2000 <dd>Perform the <a href="#i_select">select operation</a> on
2001 constants.</dd>
2002
2003 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2004 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2005
2006 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2007 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2008
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]2009 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
2010 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
2011
2012 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
2013 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
2014
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2015 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
2016
2017 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2018 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2019
2020 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
2021
2022 <dd>Perform the <a href="#i_insertelement">insertelement
2023 operation</a> on constants.</dd>
2024
2025
2026 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
2027
2028 <dd>Perform the <a href="#i_shufflevector">shufflevector
2029 operation</a> on constants.</dd>
2030
2031 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
2032
2033 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2034 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
2035 binary</a> operations. The constraints on operands are the same as those for
2036 the corresponding instruction (e.g. no bitwise operations on floating point
2037 values are allowed).</dd>
2038</dl>
2039</div>
2040
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2041<!-- ======================================================================= -->
2042<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2043</div>
2044
2045<div class="doc_text">
2046
2047<p>Embedded metadata provides a way to attach arbitrary data to the
2048instruction stream without affecting the behaviour of the program. There are
2049two metadata primitives, strings and nodes. All metadata has the type of an
2050empty struct and is identified in syntax by a preceding exclamation point
2051('<tt>!</tt>').
2052</p>
2053
2054<p>A metadata string is a string surrounded by double quotes. It can contain
2055any character by escaping non-printable characters with "\xx" where "xx" is
2056the two digit hex code. For example: "<tt>!"test\00"</tt>".
2057</p>
2058
2059<p>Metadata nodes are represented with notation similar to structure constants
2060(a comma separated list of elements, surrounded by braces and preceeded by an
2061exclamation point). For example: "<tt>!{ { } !"test\00", i32 10}</tt>".
2062</p>
2063
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2064<p>A metadata node will attempt to track changes to the values it holds. In
2065the event that a value is deleted, it will be replaced with a typeless
2066"<tt>null</tt>", such as "<tt>{ } !{null, i32 0}</tt>".</p>
2067
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2068<p>Optimizations may rely on metadata to provide additional information about
2069the program that isn't available in the instructions, or that isn't easily
2070computable. Similarly, the code generator may expect a certain metadata format
2071to be used to express debugging information.</p>
2072</div>
2073
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2074<!-- *********************************************************************** -->
2075<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2076<!-- *********************************************************************** -->
2077
2078<!-- ======================================================================= -->
2079<div class="doc_subsection">
2080<a name="inlineasm">Inline Assembler Expressions</a>
2081</div>
2082
2083<div class="doc_text">
2084
2085<p>
2086LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
2087Module-Level Inline Assembly</a>) through the use of a special value. This
2088value represents the inline assembler as a string (containing the instructions
2089to emit), a list of operand constraints (stored as a string), and a flag that
2090indicates whether or not the inline asm expression has side effects. An example
2091inline assembler expression is:
2092</p>
2093
2094<div class="doc_code">
2095<pre>
2096i32 (i32) asm "bswap $0", "=r,r"
2097</pre>
2098</div>
2099
2100<p>
2101Inline assembler expressions may <b>only</b> be used as the callee operand of
2102a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
2103</p>
2104
2105<div class="doc_code">
2106<pre>
2107%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2108</pre>
2109</div>
2110
2111<p>
2112Inline asms with side effects not visible in the constraint list must be marked
2113as having side effects. This is done through the use of the
2114'<tt>sideeffect</tt>' keyword, like so:
2115</p>
2116
2117<div class="doc_code">
2118<pre>
2119call void asm sideeffect "eieio", ""()
2120</pre>
2121</div>
2122
2123<p>TODO: The format of the asm and constraints string still need to be
2124documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]2125need to be documented). This is probably best done by reference to another
2126document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2127</p>
2128
2129</div>
2130
2131<!-- *********************************************************************** -->
2132<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2133<!-- *********************************************************************** -->
2134
2135<div class="doc_text">
2136
2137<p>The LLVM instruction set consists of several different
2138classifications of instructions: <a href="#terminators">terminator
2139instructions</a>, <a href="#binaryops">binary instructions</a>,
2140<a href="#bitwiseops">bitwise binary instructions</a>, <a
2141 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
2142instructions</a>.</p>
2143
2144</div>
2145
2146<!-- ======================================================================= -->
2147<div class="doc_subsection"> <a name="terminators">Terminator
2148Instructions</a> </div>
2149
2150<div class="doc_text">
2151
2152<p>As mentioned <a href="#functionstructure">previously</a>, every
2153basic block in a program ends with a "Terminator" instruction, which
2154indicates which block should be executed after the current block is
2155finished. These terminator instructions typically yield a '<tt>void</tt>'
2156value: they produce control flow, not values (the one exception being
2157the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2158<p>There are six different terminator instructions: the '<a
2159 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
2160instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
2161the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
2162 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
2163 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
2164
2165</div>
2166
2167<!-- _______________________________________________________________________ -->
2168<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2169Instruction</a> </div>
2170<div class="doc_text">
2171<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2172<pre>
2173 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2174 ret void <i>; Return from void function</i>
2175</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2176
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2177<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2178
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2179<p>The '<tt>ret</tt>' instruction is used to return control flow (and
2180optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2181<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2182returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2183control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2184
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2185<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2186
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2187<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
2188the return value. The type of the return value must be a
2189'<a href="#t_firstclass">first class</a>' type.</p>
2190
2191<p>A function is not <a href="#wellformed">well formed</a> if
2192it it has a non-void return type and contains a '<tt>ret</tt>'
2193instruction with no return value or a return value with a type that
2194does not match its type, or if it has a void return type and contains
2195a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2196
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2197<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2198
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2199<p>When the '<tt>ret</tt>' instruction is executed, control flow
2200returns back to the calling function's context. If the caller is a "<a
2201 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
2202the instruction after the call. If the caller was an "<a
2203 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
2204at the beginning of the "normal" destination block. If the instruction
2205returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2206return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2207
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2208<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2209
2210<pre>
2211 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2212 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2213 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2214</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2215
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2216<p>Note that the code generator does not yet fully support large
2217 return values. The specific sizes that are currently supported are
2218 dependent on the target. For integers, on 32-bit targets the limit
2219 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2220 For aggregate types, the current limits are dependent on the element
2221 types; for example targets are often limited to 2 total integer
2222 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2223
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2224</div>
2225<!-- _______________________________________________________________________ -->
2226<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
2227<div class="doc_text">
2228<h5>Syntax:</h5>
2229<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
2230</pre>
2231<h5>Overview:</h5>
2232<p>The '<tt>br</tt>' instruction is used to cause control flow to
2233transfer to a different basic block in the current function. There are
2234two forms of this instruction, corresponding to a conditional branch
2235and an unconditional branch.</p>
2236<h5>Arguments:</h5>
2237<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
2238single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
2239unconditional form of the '<tt>br</tt>' instruction takes a single
2240'<tt>label</tt>' value as a target.</p>
2241<h5>Semantics:</h5>
2242<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2243argument is evaluated. If the value is <tt>true</tt>, control flows
2244to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2245control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2246<h5>Example:</h5>
Chris Lattner95127832009-05-09 18:11:50 +0000[diff] [blame]2247<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2248 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2249</div>
2250<!-- _______________________________________________________________________ -->
2251<div class="doc_subsubsection">
2252 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2253</div>
2254
2255<div class="doc_text">
2256<h5>Syntax:</h5>
2257
2258<pre>
2259 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2260</pre>
2261
2262<h5>Overview:</h5>
2263
2264<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2265several different places. It is a generalization of the '<tt>br</tt>'
2266instruction, allowing a branch to occur to one of many possible
2267destinations.</p>
2268
2269
2270<h5>Arguments:</h5>
2271
2272<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2273comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2274an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2275table is not allowed to contain duplicate constant entries.</p>
2276
2277<h5>Semantics:</h5>
2278
2279<p>The <tt>switch</tt> instruction specifies a table of values and
2280destinations. When the '<tt>switch</tt>' instruction is executed, this
2281table is searched for the given value. If the value is found, control flow is
2282transfered to the corresponding destination; otherwise, control flow is
2283transfered to the default destination.</p>
2284
2285<h5>Implementation:</h5>
2286
2287<p>Depending on properties of the target machine and the particular
2288<tt>switch</tt> instruction, this instruction may be code generated in different
2289ways. For example, it could be generated as a series of chained conditional
2290branches or with a lookup table.</p>
2291
2292<h5>Example:</h5>
2293
2294<pre>
2295 <i>; Emulate a conditional br instruction</i>
2296 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2297 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2298
2299 <i>; Emulate an unconditional br instruction</i>
2300 switch i32 0, label %dest [ ]
2301
2302 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2303 switch i32 %val, label %otherwise [ i32 0, label %onzero
2304 i32 1, label %onone
2305 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2306</pre>
2307</div>
2308
2309<!-- _______________________________________________________________________ -->
2310<div class="doc_subsubsection">
2311 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2312</div>
2313
2314<div class="doc_text">
2315
2316<h5>Syntax:</h5>
2317
2318<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2319 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2320 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2321</pre>
2322
2323<h5>Overview:</h5>
2324
2325<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2326function, with the possibility of control flow transfer to either the
2327'<tt>normal</tt>' label or the
2328'<tt>exception</tt>' label. If the callee function returns with the
2329"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2330"normal" label. If the callee (or any indirect callees) returns with the "<a
2331href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2332continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2333
2334<h5>Arguments:</h5>
2335
2336<p>This instruction requires several arguments:</p>
2337
2338<ol>
2339 <li>
2340 The optional "cconv" marker indicates which <a href="#callingconv">calling
2341 convention</a> the call should use. If none is specified, the call defaults
2342 to using C calling conventions.
2343 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2344
2345 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2346 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2347 and '<tt>inreg</tt>' attributes are valid here.</li>
2348
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2349 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2350 function value being invoked. In most cases, this is a direct function
2351 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2352 an arbitrary pointer to function value.
2353 </li>
2354
2355 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2356 function to be invoked. </li>
2357
2358 <li>'<tt>function args</tt>': argument list whose types match the function
2359 signature argument types. If the function signature indicates the function
2360 accepts a variable number of arguments, the extra arguments can be
2361 specified. </li>
2362
2363 <li>'<tt>normal label</tt>': the label reached when the called function
2364 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2365
2366 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2367 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2368
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2369 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2370 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2371 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2372</ol>
2373
2374<h5>Semantics:</h5>
2375
2376<p>This instruction is designed to operate as a standard '<tt><a
2377href="#i_call">call</a></tt>' instruction in most regards. The primary
2378difference is that it establishes an association with a label, which is used by
2379the runtime library to unwind the stack.</p>
2380
2381<p>This instruction is used in languages with destructors to ensure that proper
2382cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2383exception. Additionally, this is important for implementation of
2384'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2385
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame^]2386<p>It is not valid to reference the return value of an invoke call from
2387anywhere not dominated by the normal label, since an unwind does not
2388provide a return value.</p>
2389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2390<h5>Example:</h5>
2391<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2392 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2393 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2394 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2395 unwind label %TestCleanup <i>; {i32}:retval set</i>
2396</pre>
2397</div>
2398
2399
2400<!-- _______________________________________________________________________ -->
2401
2402<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2403Instruction</a> </div>
2404
2405<div class="doc_text">
2406
2407<h5>Syntax:</h5>
2408<pre>
2409 unwind
2410</pre>
2411
2412<h5>Overview:</h5>
2413
2414<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2415at the first callee in the dynamic call stack which used an <a
2416href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2417primarily used to implement exception handling.</p>
2418
2419<h5>Semantics:</h5>
2420
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2421<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2422immediately halt. The dynamic call stack is then searched for the first <a
2423href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2424execution continues at the "exceptional" destination block specified by the
2425<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2426dynamic call chain, undefined behavior results.</p>
2427</div>
2428
2429<!-- _______________________________________________________________________ -->
2430
2431<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2432Instruction</a> </div>
2433
2434<div class="doc_text">
2435
2436<h5>Syntax:</h5>
2437<pre>
2438 unreachable
2439</pre>
2440
2441<h5>Overview:</h5>
2442
2443<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2444instruction is used to inform the optimizer that a particular portion of the
2445code is not reachable. This can be used to indicate that the code after a
2446no-return function cannot be reached, and other facts.</p>
2447
2448<h5>Semantics:</h5>
2449
2450<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2451</div>
2452
2453
2454
2455<!-- ======================================================================= -->
2456<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2457<div class="doc_text">
2458<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2459program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2460produce a single value. The operands might represent
2461multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2462The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2463<p>There are several different binary operators:</p>
2464</div>
2465<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2466<div class="doc_subsubsection">
2467 <a name="i_add">'<tt>add</tt>' Instruction</a>
2468</div>
2469
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2470<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2471
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2472<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2473
2474<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2475 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2476</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2477
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2478<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2479
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2480<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2481
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2482<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2483
2484<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2485 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2486 <a href="#t_vector">vector</a> values. Both arguments must have identical
2487 types.</p>
2488
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2489<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2490
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2491<p>The value produced is the integer or floating point sum of the two
2492operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2493
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2494<p>If an integer sum has unsigned overflow, the result returned is the
2495mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2496the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2497
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2498<p>Because LLVM integers use a two's complement representation, this
2499instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2501<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2502
2503<pre>
2504 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2505</pre>
2506</div>
2507<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2508<div class="doc_subsubsection">
2509 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2510</div>
2511
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2512<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2513
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2514<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2515
2516<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2517 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2518</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2519
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2520<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2521
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2522<p>The '<tt>sub</tt>' instruction returns the difference of its two
2523operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2524
2525<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2526'<tt>neg</tt>' instruction present in most other intermediate
2527representations.</p>
2528
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2529<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2530
2531<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2532 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2533 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2534 types.</p>
2535
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2536<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2537
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2538<p>The value produced is the integer or floating point difference of
2539the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2540
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2541<p>If an integer difference has unsigned overflow, the result returned is the
2542mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2543the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2544
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2545<p>Because LLVM integers use a two's complement representation, this
2546instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2547
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2548<h5>Example:</h5>
2549<pre>
2550 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2551 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2552</pre>
2553</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2554
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2555<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2556<div class="doc_subsubsection">
2557 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2558</div>
2559
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2560<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2561
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2562<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2563<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2564</pre>
2565<h5>Overview:</h5>
2566<p>The '<tt>mul</tt>' instruction returns the product of its two
2567operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2568
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2569<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2570
2571<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2572href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2573or <a href="#t_vector">vector</a> values. Both arguments must have identical
2574types.</p>
2575
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2576<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2577
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2578<p>The value produced is the integer or floating point product of the
2579two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2580
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2581<p>If the result of an integer multiplication has unsigned overflow,
2582the result returned is the mathematical result modulo
25832<sup>n</sup>, where n is the bit width of the result.</p>
2584<p>Because LLVM integers use a two's complement representation, and the
2585result is the same width as the operands, this instruction returns the
2586correct result for both signed and unsigned integers. If a full product
2587(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2588should be sign-extended or zero-extended as appropriate to the
2589width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2590<h5>Example:</h5>
2591<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2592</pre>
2593</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2594
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2595<!-- _______________________________________________________________________ -->
2596<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2597</a></div>
2598<div class="doc_text">
2599<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2600<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2601</pre>
2602<h5>Overview:</h5>
2603<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2604operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2605
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2606<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2607
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2608<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2609<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2610values. Both arguments must have identical types.</p>
2611
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2612<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2613
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2614<p>The value produced is the unsigned integer quotient of the two operands.</p>
2615<p>Note that unsigned integer division and signed integer division are distinct
2616operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2617<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2618<h5>Example:</h5>
2619<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2620</pre>
2621</div>
2622<!-- _______________________________________________________________________ -->
2623<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2624</a> </div>
2625<div class="doc_text">
2626<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2627<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2628 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2629</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2630
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2631<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2632
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2633<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2634operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2635
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2636<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2637
2638<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2639<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2640values. Both arguments must have identical types.</p>
2641
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2642<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2643<p>The value produced is the signed integer quotient of the two operands rounded towards zero.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2644<p>Note that signed integer division and unsigned integer division are distinct
2645operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2646<p>Division by zero leads to undefined behavior. Overflow also leads to
2647undefined behavior; this is a rare case, but can occur, for example,
2648by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2649<h5>Example:</h5>
2650<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2651</pre>
2652</div>
2653<!-- _______________________________________________________________________ -->
2654<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2655Instruction</a> </div>
2656<div class="doc_text">
2657<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2658<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2659 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2660</pre>
2661<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2663<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2664operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2665
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2666<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2667
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2668<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2669<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2670of floating point values. Both arguments must have identical types.</p>
2671
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2672<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2673
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2674<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2675
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2676<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2677
2678<pre>
2679 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2680</pre>
2681</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2682
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2683<!-- _______________________________________________________________________ -->
2684<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2685</div>
2686<div class="doc_text">
2687<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2688<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2689</pre>
2690<h5>Overview:</h5>
2691<p>The '<tt>urem</tt>' instruction returns the remainder from the
2692unsigned division of its two arguments.</p>
2693<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2694<p>The two arguments to the '<tt>urem</tt>' instruction must be
2695<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2696values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2697<h5>Semantics:</h5>
2698<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2699This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2700<p>Note that unsigned integer remainder and signed integer remainder are
2701distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2702<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2703<h5>Example:</h5>
2704<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2705</pre>
2706
2707</div>
2708<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2709<div class="doc_subsubsection">
2710 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2711</div>
2712
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2713<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2714
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2715<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2716
2717<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2718 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2719</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2720
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2721<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2722
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2723<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2724signed division of its two operands. This instruction can also take
2725<a href="#t_vector">vector</a> versions of the values in which case
2726the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2727
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2728<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2729
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2730<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2731<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2732values. Both arguments must have identical types.</p>
2733
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2734<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2735
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2736<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2737has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2738operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2739a value. For more information about the difference, see <a
2740 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2741Math Forum</a>. For a table of how this is implemented in various languages,
2742please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2743Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2744<p>Note that signed integer remainder and unsigned integer remainder are
2745distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2746<p>Taking the remainder of a division by zero leads to undefined behavior.
2747Overflow also leads to undefined behavior; this is a rare case, but can occur,
2748for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2749(The remainder doesn't actually overflow, but this rule lets srem be
2750implemented using instructions that return both the result of the division
2751and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2752<h5>Example:</h5>
2753<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2754</pre>
2755
2756</div>
2757<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2758<div class="doc_subsubsection">
2759 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2760
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2761<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2762
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2763<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2764<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2765</pre>
2766<h5>Overview:</h5>
2767<p>The '<tt>frem</tt>' instruction returns the remainder from the
2768division of its two operands.</p>
2769<h5>Arguments:</h5>
2770<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2771<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2772of floating point values. Both arguments must have identical types.</p>
2773
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2774<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2775
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2776<p>This instruction returns the <i>remainder</i> of a division.
2777The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2778
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2779<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2780
2781<pre>
2782 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2783</pre>
2784</div>
2785
2786<!-- ======================================================================= -->
2787<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2788Operations</a> </div>
2789<div class="doc_text">
2790<p>Bitwise binary operators are used to do various forms of
2791bit-twiddling in a program. They are generally very efficient
2792instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2793instructions. They require two operands of the same type, execute an operation on them,
2794and produce a single value. The resulting value is the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2795</div>
2796
2797<!-- _______________________________________________________________________ -->
2798<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2799Instruction</a> </div>
2800<div class="doc_text">
2801<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2802<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2803</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2804
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2805<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2806
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2807<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2808the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2809
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2810<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2811
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2812<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2813 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2814type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2815
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2816<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2817
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2818<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2819where n is the width of the result. If <tt>op2</tt> is (statically or dynamically) negative or
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2820equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2821If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2822corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2823
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2824<h5>Example:</h5><pre>
2825 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2826 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2827 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2828 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2829 &lt;result&gt; = shl &lt;2 x i32&gt; &lt; i32 1, i32 1&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 2, i32 4&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2830</pre>
2831</div>
2832<!-- _______________________________________________________________________ -->
2833<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2834Instruction</a> </div>
2835<div class="doc_text">
2836<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2837<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2838</pre>
2839
2840<h5>Overview:</h5>
2841<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2842operand shifted to the right a specified number of bits with zero fill.</p>
2843
2844<h5>Arguments:</h5>
2845<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2846<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2847type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2848
2849<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2850
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2851<p>This instruction always performs a logical shift right operation. The most
2852significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2853shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2854the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2855vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2856amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2857
2858<h5>Example:</h5>
2859<pre>
2860 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2861 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2862 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2863 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2864 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2865 &lt;result&gt; = lshr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0x7FFFFFFF, i32 1&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2866</pre>
2867</div>
2868
2869<!-- _______________________________________________________________________ -->
2870<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2871Instruction</a> </div>
2872<div class="doc_text">
2873
2874<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2875<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2876</pre>
2877
2878<h5>Overview:</h5>
2879<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2880operand shifted to the right a specified number of bits with sign extension.</p>
2881
2882<h5>Arguments:</h5>
2883<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2884<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2885type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2886
2887<h5>Semantics:</h5>
2888<p>This instruction always performs an arithmetic shift right operation,
2889The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2890of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2891larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
2892arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2893corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2894
2895<h5>Example:</h5>
2896<pre>
2897 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2898 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2899 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2900 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2901 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2902 &lt;result&gt; = ashr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 3&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 -1, i32 0&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2903</pre>
2904</div>
2905
2906<!-- _______________________________________________________________________ -->
2907<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2908Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2909
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2910<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2911
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2912<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2913
2914<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2915 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2916</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2917
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2918<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2919
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2920<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2921its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2922
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2923<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2924
2925<p>The two arguments to the '<tt>and</tt>' instruction must be
2926<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2927values. Both arguments must have identical types.</p>
2928
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2929<h5>Semantics:</h5>
2930<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2931<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2932<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2933<table border="1" cellspacing="0" cellpadding="4">
2934 <tbody>
2935 <tr>
2936 <td>In0</td>
2937 <td>In1</td>
2938 <td>Out</td>
2939 </tr>
2940 <tr>
2941 <td>0</td>
2942 <td>0</td>
2943 <td>0</td>
2944 </tr>
2945 <tr>
2946 <td>0</td>
2947 <td>1</td>
2948 <td>0</td>
2949 </tr>
2950 <tr>
2951 <td>1</td>
2952 <td>0</td>
2953 <td>0</td>
2954 </tr>
2955 <tr>
2956 <td>1</td>
2957 <td>1</td>
2958 <td>1</td>
2959 </tr>
2960 </tbody>
2961</table>
2962</div>
2963<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2964<pre>
2965 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2966 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2967 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2968</pre>
2969</div>
2970<!-- _______________________________________________________________________ -->
2971<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2972<div class="doc_text">
2973<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2974<pre> &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2975</pre>
2976<h5>Overview:</h5>
2977<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2978or of its two operands.</p>
2979<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2980
2981<p>The two arguments to the '<tt>or</tt>' instruction must be
2982<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2983values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2984<h5>Semantics:</h5>
2985<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2986<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2987<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2988<table border="1" cellspacing="0" cellpadding="4">
2989 <tbody>
2990 <tr>
2991 <td>In0</td>
2992 <td>In1</td>
2993 <td>Out</td>
2994 </tr>
2995 <tr>
2996 <td>0</td>
2997 <td>0</td>
2998 <td>0</td>
2999 </tr>
3000 <tr>
3001 <td>0</td>
3002 <td>1</td>
3003 <td>1</td>
3004 </tr>
3005 <tr>
3006 <td>1</td>
3007 <td>0</td>
3008 <td>1</td>
3009 </tr>
3010 <tr>
3011 <td>1</td>
3012 <td>1</td>
3013 <td>1</td>
3014 </tr>
3015 </tbody>
3016</table>
3017</div>
3018<h5>Example:</h5>
3019<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
3020 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3021 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3022</pre>
3023</div>
3024<!-- _______________________________________________________________________ -->
3025<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3026Instruction</a> </div>
3027<div class="doc_text">
3028<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3029<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3030</pre>
3031<h5>Overview:</h5>
3032<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
3033or of its two operands. The <tt>xor</tt> is used to implement the
3034"one's complement" operation, which is the "~" operator in C.</p>
3035<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3036<p>The two arguments to the '<tt>xor</tt>' instruction must be
3037<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3038values. Both arguments must have identical types.</p>
3039
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3040<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3041
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3042<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
3043<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3044<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3045<table border="1" cellspacing="0" cellpadding="4">
3046 <tbody>
3047 <tr>
3048 <td>In0</td>
3049 <td>In1</td>
3050 <td>Out</td>
3051 </tr>
3052 <tr>
3053 <td>0</td>
3054 <td>0</td>
3055 <td>0</td>
3056 </tr>
3057 <tr>
3058 <td>0</td>
3059 <td>1</td>
3060 <td>1</td>
3061 </tr>
3062 <tr>
3063 <td>1</td>
3064 <td>0</td>
3065 <td>1</td>
3066 </tr>
3067 <tr>
3068 <td>1</td>
3069 <td>1</td>
3070 <td>0</td>
3071 </tr>
3072 </tbody>
3073</table>
3074</div>
3075<p> </p>
3076<h5>Example:</h5>
3077<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
3078 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3079 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3080 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3081</pre>
3082</div>
3083
3084<!-- ======================================================================= -->
3085<div class="doc_subsection">
3086 <a name="vectorops">Vector Operations</a>
3087</div>
3088
3089<div class="doc_text">
3090
3091<p>LLVM supports several instructions to represent vector operations in a
3092target-independent manner. These instructions cover the element-access and
3093vector-specific operations needed to process vectors effectively. While LLVM
3094does directly support these vector operations, many sophisticated algorithms
3095will want to use target-specific intrinsics to take full advantage of a specific
3096target.</p>
3097
3098</div>
3099
3100<!-- _______________________________________________________________________ -->
3101<div class="doc_subsubsection">
3102 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3103</div>
3104
3105<div class="doc_text">
3106
3107<h5>Syntax:</h5>
3108
3109<pre>
3110 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3111</pre>
3112
3113<h5>Overview:</h5>
3114
3115<p>
3116The '<tt>extractelement</tt>' instruction extracts a single scalar
3117element from a vector at a specified index.
3118</p>
3119
3120
3121<h5>Arguments:</h5>
3122
3123<p>
3124The first operand of an '<tt>extractelement</tt>' instruction is a
3125value of <a href="#t_vector">vector</a> type. The second operand is
3126an index indicating the position from which to extract the element.
3127The index may be a variable.</p>
3128
3129<h5>Semantics:</h5>
3130
3131<p>
3132The result is a scalar of the same type as the element type of
3133<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3134<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3135results are undefined.
3136</p>
3137
3138<h5>Example:</h5>
3139
3140<pre>
3141 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3142</pre>
3143</div>
3144
3145
3146<!-- _______________________________________________________________________ -->
3147<div class="doc_subsubsection">
3148 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3149</div>
3150
3151<div class="doc_text">
3152
3153<h5>Syntax:</h5>
3154
3155<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3156 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3157</pre>
3158
3159<h5>Overview:</h5>
3160
3161<p>
3162The '<tt>insertelement</tt>' instruction inserts a scalar
3163element into a vector at a specified index.
3164</p>
3165
3166
3167<h5>Arguments:</h5>
3168
3169<p>
3170The first operand of an '<tt>insertelement</tt>' instruction is a
3171value of <a href="#t_vector">vector</a> type. The second operand is a
3172scalar value whose type must equal the element type of the first
3173operand. The third operand is an index indicating the position at
3174which to insert the value. The index may be a variable.</p>
3175
3176<h5>Semantics:</h5>
3177
3178<p>
3179The result is a vector of the same type as <tt>val</tt>. Its
3180element values are those of <tt>val</tt> except at position
3181<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
3182exceeds the length of <tt>val</tt>, the results are undefined.
3183</p>
3184
3185<h5>Example:</h5>
3186
3187<pre>
3188 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3189</pre>
3190</div>
3191
3192<!-- _______________________________________________________________________ -->
3193<div class="doc_subsubsection">
3194 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3195</div>
3196
3197<div class="doc_text">
3198
3199<h5>Syntax:</h5>
3200
3201<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3202 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;m x i32&gt; &lt;mask&gt; <i>; yields &lt;m x &lt;ty&gt;&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3203</pre>
3204
3205<h5>Overview:</h5>
3206
3207<p>
3208The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3209from two input vectors, returning a vector with the same element type as
3210the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3211</p>
3212
3213<h5>Arguments:</h5>
3214
3215<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3216The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3217with types that match each other. The third argument is a shuffle mask whose
3218element type is always 'i32'. The result of the instruction is a vector whose
3219length is the same as the shuffle mask and whose element type is the same as
3220the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3221</p>
3222
3223<p>
3224The shuffle mask operand is required to be a constant vector with either
3225constant integer or undef values.
3226</p>
3227
3228<h5>Semantics:</h5>
3229
3230<p>
3231The elements of the two input vectors are numbered from left to right across
3232both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3233the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3234gets. The element selector may be undef (meaning "don't care") and the second
3235operand may be undef if performing a shuffle from only one vector.
3236</p>
3237
3238<h5>Example:</h5>
3239
3240<pre>
3241 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3242 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3243 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3244 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3245 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3246 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3247 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3248 &lt;8 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7 &gt; <i>; yields &lt;8 x i32&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3249</pre>
3250</div>
3251
3252
3253<!-- ======================================================================= -->
3254<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3255 <a name="aggregateops">Aggregate Operations</a>
3256</div>
3257
3258<div class="doc_text">
3259
3260<p>LLVM supports several instructions for working with aggregate values.
3261</p>
3262
3263</div>
3264
3265<!-- _______________________________________________________________________ -->
3266<div class="doc_subsubsection">
3267 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3268</div>
3269
3270<div class="doc_text">
3271
3272<h5>Syntax:</h5>
3273
3274<pre>
3275 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3276</pre>
3277
3278<h5>Overview:</h5>
3279
3280<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3281The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3282or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3283</p>
3284
3285
3286<h5>Arguments:</h5>
3287
3288<p>
3289The first operand of an '<tt>extractvalue</tt>' instruction is a
3290value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3291type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3292in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3293'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3294</p>
3295
3296<h5>Semantics:</h5>
3297
3298<p>
3299The result is the value at the position in the aggregate specified by
3300the index operands.
3301</p>
3302
3303<h5>Example:</h5>
3304
3305<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3306 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3307</pre>
3308</div>
3309
3310
3311<!-- _______________________________________________________________________ -->
3312<div class="doc_subsubsection">
3313 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3314</div>
3315
3316<div class="doc_text">
3317
3318<h5>Syntax:</h5>
3319
3320<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3321 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3322</pre>
3323
3324<h5>Overview:</h5>
3325
3326<p>
3327The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3328into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3329</p>
3330
3331
3332<h5>Arguments:</h5>
3333
3334<p>
3335The first operand of an '<tt>insertvalue</tt>' instruction is a
3336value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3337The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3338The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3339indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3340indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3341'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3342The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3343by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3344</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3345
3346<h5>Semantics:</h5>
3347
3348<p>
3349The result is an aggregate of the same type as <tt>val</tt>. Its
3350value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3351specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3352</p>
3353
3354<h5>Example:</h5>
3355
3356<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3357 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3358</pre>
3359</div>
3360
3361
3362<!-- ======================================================================= -->
3363<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3364 <a name="memoryops">Memory Access and Addressing Operations</a>
3365</div>
3366
3367<div class="doc_text">
3368
3369<p>A key design point of an SSA-based representation is how it
3370represents memory. In LLVM, no memory locations are in SSA form, which
3371makes things very simple. This section describes how to read, write,
3372allocate, and free memory in LLVM.</p>
3373
3374</div>
3375
3376<!-- _______________________________________________________________________ -->
3377<div class="doc_subsubsection">
3378 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3379</div>
3380
3381<div class="doc_text">
3382
3383<h5>Syntax:</h5>
3384
3385<pre>
3386 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3387</pre>
3388
3389<h5>Overview:</h5>
3390
3391<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3392heap and returns a pointer to it. The object is always allocated in the generic
3393address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3394
3395<h5>Arguments:</h5>
3396
3397<p>The '<tt>malloc</tt>' instruction allocates
3398<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3399bytes of memory from the operating system and returns a pointer of the
3400appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3401number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3402If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3403be aligned to at least that boundary. If not specified, or if zero, the target can
3404choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3405
3406<p>'<tt>type</tt>' must be a sized type.</p>
3407
3408<h5>Semantics:</h5>
3409
3410<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3411a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3412result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3413
3414<h5>Example:</h5>
3415
3416<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3417 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3418
3419 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3420 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3421 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3422 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3423 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3424</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3425
3426<p>Note that the code generator does not yet respect the
3427 alignment value.</p>
3428
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3429</div>
3430
3431<!-- _______________________________________________________________________ -->
3432<div class="doc_subsubsection">
3433 <a name="i_free">'<tt>free</tt>' Instruction</a>
3434</div>
3435
3436<div class="doc_text">
3437
3438<h5>Syntax:</h5>
3439
3440<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3441 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3442</pre>
3443
3444<h5>Overview:</h5>
3445
3446<p>The '<tt>free</tt>' instruction returns memory back to the unused
3447memory heap to be reallocated in the future.</p>
3448
3449<h5>Arguments:</h5>
3450
3451<p>'<tt>value</tt>' shall be a pointer value that points to a value
3452that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3453instruction.</p>
3454
3455<h5>Semantics:</h5>
3456
3457<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3458after this instruction executes. If the pointer is null, the operation
3459is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3460
3461<h5>Example:</h5>
3462
3463<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3464 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3465 free [4 x i8]* %array
3466</pre>
3467</div>
3468
3469<!-- _______________________________________________________________________ -->
3470<div class="doc_subsubsection">
3471 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3472</div>
3473
3474<div class="doc_text">
3475
3476<h5>Syntax:</h5>
3477
3478<pre>
3479 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3480</pre>
3481
3482<h5>Overview:</h5>
3483
3484<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3485currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3486returns to its caller. The object is always allocated in the generic address
3487space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3488
3489<h5>Arguments:</h5>
3490
3491<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3492bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3493appropriate type to the program. If "NumElements" is specified, it is the
3494number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3495If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3496to be aligned to at least that boundary. If not specified, or if zero, the target
3497can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3498
3499<p>'<tt>type</tt>' may be any sized type.</p>
3500
3501<h5>Semantics:</h5>
3502
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3503<p>Memory is allocated; a pointer is returned. The operation is undefined if
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3504there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3505memory is automatically released when the function returns. The '<tt>alloca</tt>'
3506instruction is commonly used to represent automatic variables that must
3507have an address available. When the function returns (either with the <tt><a
3508 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3509instructions), the memory is reclaimed. Allocating zero bytes
3510is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3511
3512<h5>Example:</h5>
3513
3514<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3515 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3516 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3517 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3518 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3519</pre>
3520</div>
3521
3522<!-- _______________________________________________________________________ -->
3523<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3524Instruction</a> </div>
3525<div class="doc_text">
3526<h5>Syntax:</h5>
3527<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br></pre>
3528<h5>Overview:</h5>
3529<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3530<h5>Arguments:</h5>
3531<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3532address from which to load. The pointer must point to a <a
3533 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3534marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3535the number or order of execution of this <tt>load</tt> with other
3536volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3537instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3538<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3539The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3540(that is, the alignment of the memory address). A value of 0 or an
3541omitted "align" argument means that the operation has the preferential
3542alignment for the target. It is the responsibility of the code emitter
3543to ensure that the alignment information is correct. Overestimating
3544the alignment results in an undefined behavior. Underestimating the
3545alignment may produce less efficient code. An alignment of 1 is always
3546safe.
3547</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3548<h5>Semantics:</h5>
Duncan Sandsfe87fff2009-03-22 11:33:16 +0000[diff] [blame]3549<p>The location of memory pointed to is loaded. If the value being loaded
3550is of scalar type then the number of bytes read does not exceed the minimum
3551number of bytes needed to hold all bits of the type. For example, loading an
3552<tt>i24</tt> reads at most three bytes. When loading a value of a type like
3553<tt>i20</tt> with a size that is not an integral number of bytes, the result
3554is undefined if the value was not originally written using a store of the
3555same type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3556<h5>Examples:</h5>
3557<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3558 <a
3559 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3560 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3561</pre>
3562</div>
3563<!-- _______________________________________________________________________ -->
3564<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3565Instruction</a> </div>
3566<div class="doc_text">
3567<h5>Syntax:</h5>
3568<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3569 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3570</pre>
3571<h5>Overview:</h5>
3572<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3573<h5>Arguments:</h5>
3574<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3575to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3576operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3577of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3578operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3579optimizer is not allowed to modify the number or order of execution of
3580this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3581 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3582<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3583The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3584(that is, the alignment of the memory address). A value of 0 or an
3585omitted "align" argument means that the operation has the preferential
3586alignment for the target. It is the responsibility of the code emitter
3587to ensure that the alignment information is correct. Overestimating
3588the alignment results in an undefined behavior. Underestimating the
3589alignment may produce less efficient code. An alignment of 1 is always
3590safe.
3591</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3592<h5>Semantics:</h5>
3593<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
Duncan Sandsfe87fff2009-03-22 11:33:16 +0000[diff] [blame]3594at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.
3595If '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes
3596written does not exceed the minimum number of bytes needed to hold all
3597bits of the type. For example, storing an <tt>i24</tt> writes at most
3598three bytes. When writing a value of a type like <tt>i20</tt> with a
3599size that is not an integral number of bytes, it is unspecified what
3600happens to the extra bits that do not belong to the type, but they will
3601typically be overwritten.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3602<h5>Example:</h5>
3603<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3604 store i32 3, i32* %ptr <i>; yields {void}</i>
3605 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3606</pre>
3607</div>
3608
3609<!-- _______________________________________________________________________ -->
3610<div class="doc_subsubsection">
3611 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3612</div>
3613
3614<div class="doc_text">
3615<h5>Syntax:</h5>
3616<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3617 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3618</pre>
3619
3620<h5>Overview:</h5>
3621
3622<p>
3623The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3624subelement of an aggregate data structure. It performs address calculation only
3625and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3626
3627<h5>Arguments:</h5>
3628
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3629<p>The first argument is always a pointer, and forms the basis of the
3630calculation. The remaining arguments are indices, that indicate which of the
3631elements of the aggregate object are indexed. The interpretation of each index
3632is dependent on the type being indexed into. The first index always indexes the
3633pointer value given as the first argument, the second index indexes a value of
3634the type pointed to (not necessarily the value directly pointed to, since the
3635first index can be non-zero), etc. The first type indexed into must be a pointer
3636value, subsequent types can be arrays, vectors and structs. Note that subsequent
3637types being indexed into can never be pointers, since that would require loading
3638the pointer before continuing calculation.</p>
3639
3640<p>The type of each index argument depends on the type it is indexing into.
3641When indexing into a (packed) structure, only <tt>i32</tt> integer
3642<b>constants</b> are allowed. When indexing into an array, pointer or vector,
Sanjiv Guptaa2e72d92009-04-27 03:21:00 +0000[diff] [blame]3643integers of any width are allowed (also non-constants).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3644
3645<p>For example, let's consider a C code fragment and how it gets
3646compiled to LLVM:</p>
3647
3648<div class="doc_code">
3649<pre>
3650struct RT {
3651 char A;
3652 int B[10][20];
3653 char C;
3654};
3655struct ST {
3656 int X;
3657 double Y;
3658 struct RT Z;
3659};
3660
3661int *foo(struct ST *s) {
3662 return &amp;s[1].Z.B[5][13];
3663}
3664</pre>
3665</div>
3666
3667<p>The LLVM code generated by the GCC frontend is:</p>
3668
3669<div class="doc_code">
3670<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]3671%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3672%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3673
3674define i32* %foo(%ST* %s) {
3675entry:
3676 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3677 ret i32* %reg
3678}
3679</pre>
3680</div>
3681
3682<h5>Semantics:</h5>
3683
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3684<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3685type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3686}</tt>' type, a structure. The second index indexes into the third element of
3687the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3688i8 }</tt>' type, another structure. The third index indexes into the second
3689element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3690array. The two dimensions of the array are subscripted into, yielding an
3691'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3692to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3693
3694<p>Note that it is perfectly legal to index partially through a
3695structure, returning a pointer to an inner element. Because of this,
3696the LLVM code for the given testcase is equivalent to:</p>
3697
3698<pre>
3699 define i32* %foo(%ST* %s) {
3700 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3701 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3702 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3703 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3704 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3705 ret i32* %t5
3706 }
3707</pre>
3708
Chris Lattner50609942009-03-09 20:55:18 +0000[diff] [blame]3709<p>Note that it is undefined to access an array out of bounds: array
3710and pointer indexes must always be within the defined bounds of the
3711array type when accessed with an instruction that dereferences the
3712pointer (e.g. a load or store instruction). The one exception for
3713this rule is zero length arrays. These arrays are defined to be
3714accessible as variable length arrays, which requires access beyond the
3715zero'th element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3716
3717<p>The getelementptr instruction is often confusing. For some more insight
3718into how it works, see <a href="GetElementPtr.html">the getelementptr
3719FAQ</a>.</p>
3720
3721<h5>Example:</h5>
3722
3723<pre>
3724 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3725 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3726 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3727 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3728 <i>; yields i8*:eptr</i>
3729 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]3730 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]3731 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3732</pre>
3733</div>
3734
3735<!-- ======================================================================= -->
3736<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3737</div>
3738<div class="doc_text">
3739<p>The instructions in this category are the conversion instructions (casting)
3740which all take a single operand and a type. They perform various bit conversions
3741on the operand.</p>
3742</div>
3743
3744<!-- _______________________________________________________________________ -->
3745<div class="doc_subsubsection">
3746 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3747</div>
3748<div class="doc_text">
3749
3750<h5>Syntax:</h5>
3751<pre>
3752 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3753</pre>
3754
3755<h5>Overview:</h5>
3756<p>
3757The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3758</p>
3759
3760<h5>Arguments:</h5>
3761<p>
3762The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3763be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3764and type of the result, which must be an <a href="#t_integer">integer</a>
3765type. The bit size of <tt>value</tt> must be larger than the bit size of
3766<tt>ty2</tt>. Equal sized types are not allowed.</p>
3767
3768<h5>Semantics:</h5>
3769<p>
3770The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3771and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3772larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3773It will always truncate bits.</p>
3774
3775<h5>Example:</h5>
3776<pre>
3777 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3778 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3779 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3780</pre>
3781</div>
3782
3783<!-- _______________________________________________________________________ -->
3784<div class="doc_subsubsection">
3785 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3786</div>
3787<div class="doc_text">
3788
3789<h5>Syntax:</h5>
3790<pre>
3791 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3792</pre>
3793
3794<h5>Overview:</h5>
3795<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3796<tt>ty2</tt>.</p>
3797
3798
3799<h5>Arguments:</h5>
3800<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3801<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3802also be of <a href="#t_integer">integer</a> type. The bit size of the
3803<tt>value</tt> must be smaller than the bit size of the destination type,
3804<tt>ty2</tt>.</p>
3805
3806<h5>Semantics:</h5>
3807<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3808bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3809
3810<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3811
3812<h5>Example:</h5>
3813<pre>
3814 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3815 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3816</pre>
3817</div>
3818
3819<!-- _______________________________________________________________________ -->
3820<div class="doc_subsubsection">
3821 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3822</div>
3823<div class="doc_text">
3824
3825<h5>Syntax:</h5>
3826<pre>
3827 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3828</pre>
3829
3830<h5>Overview:</h5>
3831<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3832
3833<h5>Arguments:</h5>
3834<p>
3835The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3836<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3837also be of <a href="#t_integer">integer</a> type. The bit size of the
3838<tt>value</tt> must be smaller than the bit size of the destination type,
3839<tt>ty2</tt>.</p>
3840
3841<h5>Semantics:</h5>
3842<p>
3843The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3844bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3845the type <tt>ty2</tt>.</p>
3846
3847<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3848
3849<h5>Example:</h5>
3850<pre>
3851 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3852 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3853</pre>
3854</div>
3855
3856<!-- _______________________________________________________________________ -->
3857<div class="doc_subsubsection">
3858 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3859</div>
3860
3861<div class="doc_text">
3862
3863<h5>Syntax:</h5>
3864
3865<pre>
3866 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3867</pre>
3868
3869<h5>Overview:</h5>
3870<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3871<tt>ty2</tt>.</p>
3872
3873
3874<h5>Arguments:</h5>
3875<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3876 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3877cast it to. The size of <tt>value</tt> must be larger than the size of
3878<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3879<i>no-op cast</i>.</p>
3880
3881<h5>Semantics:</h5>
3882<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3883<a href="#t_floating">floating point</a> type to a smaller
3884<a href="#t_floating">floating point</a> type. If the value cannot fit within
3885the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3886
3887<h5>Example:</h5>
3888<pre>
3889 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3890 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3891</pre>
3892</div>
3893
3894<!-- _______________________________________________________________________ -->
3895<div class="doc_subsubsection">
3896 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3897</div>
3898<div class="doc_text">
3899
3900<h5>Syntax:</h5>
3901<pre>
3902 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3903</pre>
3904
3905<h5>Overview:</h5>
3906<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3907floating point value.</p>
3908
3909<h5>Arguments:</h5>
3910<p>The '<tt>fpext</tt>' instruction takes a
3911<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3912and a <a href="#t_floating">floating point</a> type to cast it to. The source
3913type must be smaller than the destination type.</p>
3914
3915<h5>Semantics:</h5>
3916<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3917<a href="#t_floating">floating point</a> type to a larger
3918<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3919used to make a <i>no-op cast</i> because it always changes bits. Use
3920<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3921
3922<h5>Example:</h5>
3923<pre>
3924 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3925 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3926</pre>
3927</div>
3928
3929<!-- _______________________________________________________________________ -->
3930<div class="doc_subsubsection">
3931 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3932</div>
3933<div class="doc_text">
3934
3935<h5>Syntax:</h5>
3936<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3937 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3938</pre>
3939
3940<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3941<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3942unsigned integer equivalent of type <tt>ty2</tt>.
3943</p>
3944
3945<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3946<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3947scalar or vector <a href="#t_floating">floating point</a> value, and a type
3948to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3949type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3950vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3951
3952<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3953<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3954<a href="#t_floating">floating point</a> operand into the nearest (rounding
3955towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3956the results are undefined.</p>
3957
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3958<h5>Example:</h5>
3959<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3960 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3961 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3962 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3963</pre>
3964</div>
3965
3966<!-- _______________________________________________________________________ -->
3967<div class="doc_subsubsection">
3968 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3969</div>
3970<div class="doc_text">
3971
3972<h5>Syntax:</h5>
3973<pre>
3974 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3975</pre>
3976
3977<h5>Overview:</h5>
3978<p>The '<tt>fptosi</tt>' instruction converts
3979<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3980</p>
3981
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3982<h5>Arguments:</h5>
3983<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3984scalar or vector <a href="#t_floating">floating point</a> value, and a type
3985to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3986type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3987vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3988
3989<h5>Semantics:</h5>
3990<p>The '<tt>fptosi</tt>' instruction converts its
3991<a href="#t_floating">floating point</a> operand into the nearest (rounding
3992towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3993the results are undefined.</p>
3994
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3995<h5>Example:</h5>
3996<pre>
3997 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3998 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3999 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4000</pre>
4001</div>
4002
4003<!-- _______________________________________________________________________ -->
4004<div class="doc_subsubsection">
4005 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4006</div>
4007<div class="doc_text">
4008
4009<h5>Syntax:</h5>
4010<pre>
4011 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4012</pre>
4013
4014<h5>Overview:</h5>
4015<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
4016integer and converts that value to the <tt>ty2</tt> type.</p>
4017
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4018<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4019<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
4020scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4021to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4022type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4023floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4024
4025<h5>Semantics:</h5>
4026<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
4027integer quantity and converts it to the corresponding floating point value. If
4028the value cannot fit in the floating point value, the results are undefined.</p>
4029
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4030<h5>Example:</h5>
4031<pre>
4032 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4033 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4034</pre>
4035</div>
4036
4037<!-- _______________________________________________________________________ -->
4038<div class="doc_subsubsection">
4039 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4040</div>
4041<div class="doc_text">
4042
4043<h5>Syntax:</h5>
4044<pre>
4045 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4046</pre>
4047
4048<h5>Overview:</h5>
4049<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
4050integer and converts that value to the <tt>ty2</tt> type.</p>
4051
4052<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4053<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
4054scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4055to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4056type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4057floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4058
4059<h5>Semantics:</h5>
4060<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
4061integer quantity and converts it to the corresponding floating point value. If
4062the value cannot fit in the floating point value, the results are undefined.</p>
4063
4064<h5>Example:</h5>
4065<pre>
4066 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4067 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4068</pre>
4069</div>
4070
4071<!-- _______________________________________________________________________ -->
4072<div class="doc_subsubsection">
4073 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4074</div>
4075<div class="doc_text">
4076
4077<h5>Syntax:</h5>
4078<pre>
4079 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4080</pre>
4081
4082<h5>Overview:</h5>
4083<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4084the integer type <tt>ty2</tt>.</p>
4085
4086<h5>Arguments:</h5>
4087<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4088must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4089<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4090
4091<h5>Semantics:</h5>
4092<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
4093<tt>ty2</tt> by interpreting the pointer value as an integer and either
4094truncating or zero extending that value to the size of the integer type. If
4095<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4096<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4097are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4098change.</p>
4099
4100<h5>Example:</h5>
4101<pre>
4102 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4103 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4104</pre>
4105</div>
4106
4107<!-- _______________________________________________________________________ -->
4108<div class="doc_subsubsection">
4109 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4110</div>
4111<div class="doc_text">
4112
4113<h5>Syntax:</h5>
4114<pre>
4115 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4116</pre>
4117
4118<h5>Overview:</h5>
4119<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
4120a pointer type, <tt>ty2</tt>.</p>
4121
4122<h5>Arguments:</h5>
4123<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
4124value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4125<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4126
4127<h5>Semantics:</h5>
4128<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
4129<tt>ty2</tt> by applying either a zero extension or a truncation depending on
4130the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4131size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
4132the size of a pointer then a zero extension is done. If they are the same size,
4133nothing is done (<i>no-op cast</i>).</p>
4134
4135<h5>Example:</h5>
4136<pre>
4137 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4138 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4139 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4140</pre>
4141</div>
4142
4143<!-- _______________________________________________________________________ -->
4144<div class="doc_subsubsection">
4145 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4146</div>
4147<div class="doc_text">
4148
4149<h5>Syntax:</h5>
4150<pre>
4151 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4152</pre>
4153
4154<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4155
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4156<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4157<tt>ty2</tt> without changing any bits.</p>
4158
4159<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4160
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4161<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]4162a non-aggregate first class value, and a type to cast it to, which must also be
4163a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
4164<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4165and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4166type is a pointer, the destination type must also be a pointer. This
4167instruction supports bitwise conversion of vectors to integers and to vectors
4168of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4169
4170<h5>Semantics:</h5>
4171<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4172<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4173this conversion. The conversion is done as if the <tt>value</tt> had been
4174stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
4175converted to other pointer types with this instruction. To convert pointers to
4176other types, use the <a href="#i_inttoptr">inttoptr</a> or
4177<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
4178
4179<h5>Example:</h5>
4180<pre>
4181 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4182 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4183 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4184</pre>
4185</div>
4186
4187<!-- ======================================================================= -->
4188<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
4189<div class="doc_text">
4190<p>The instructions in this category are the "miscellaneous"
4191instructions, which defy better classification.</p>
4192</div>
4193
4194<!-- _______________________________________________________________________ -->
4195<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4196</div>
4197<div class="doc_text">
4198<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4199<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4200</pre>
4201<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4202<p>The '<tt>icmp</tt>' instruction returns a boolean value or
4203a vector of boolean values based on comparison
4204of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4205<h5>Arguments:</h5>
4206<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
4207the condition code indicating the kind of comparison to perform. It is not
4208a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4209</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4210<ol>
4211 <li><tt>eq</tt>: equal</li>
4212 <li><tt>ne</tt>: not equal </li>
4213 <li><tt>ugt</tt>: unsigned greater than</li>
4214 <li><tt>uge</tt>: unsigned greater or equal</li>
4215 <li><tt>ult</tt>: unsigned less than</li>
4216 <li><tt>ule</tt>: unsigned less or equal</li>
4217 <li><tt>sgt</tt>: signed greater than</li>
4218 <li><tt>sge</tt>: signed greater or equal</li>
4219 <li><tt>slt</tt>: signed less than</li>
4220 <li><tt>sle</tt>: signed less or equal</li>
4221</ol>
4222<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4223<a href="#t_pointer">pointer</a>
4224or integer <a href="#t_vector">vector</a> typed.
4225They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4226<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4227<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4228the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4229yields either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt> result, as follows:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4230</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4231<ol>
4232 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
4233 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
4234 </li>
4235 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4236 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4237 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4238 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4239 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4240 <tt>true</tt> if <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4241 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4242 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4243 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4244 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4245 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4246 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4247 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4248 <tt>true</tt> if <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4249 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4250 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4251 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4252 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4253</ol>
4254<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4255values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4256<p>If the operands are integer vectors, then they are compared
4257element by element. The result is an <tt>i1</tt> vector with
4258the same number of elements as the values being compared.
4259Otherwise, the result is an <tt>i1</tt>.
4260</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4261
4262<h5>Example:</h5>
4263<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4264 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4265 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4266 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4267 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4268 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4269</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4270
4271<p>Note that the code generator does not yet support vector types with
4272 the <tt>icmp</tt> instruction.</p>
4273
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4274</div>
4275
4276<!-- _______________________________________________________________________ -->
4277<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4278</div>
4279<div class="doc_text">
4280<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4281<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4282</pre>
4283<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4284<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4285or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4286of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4287<p>
4288If the operands are floating point scalars, then the result
4289type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4290</p>
4291<p>If the operands are floating point vectors, then the result type
4292is a vector of boolean with the same number of elements as the
4293operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4294<h5>Arguments:</h5>
4295<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4296the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4297a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4298<ol>
4299 <li><tt>false</tt>: no comparison, always returns false</li>
4300 <li><tt>oeq</tt>: ordered and equal</li>
4301 <li><tt>ogt</tt>: ordered and greater than </li>
4302 <li><tt>oge</tt>: ordered and greater than or equal</li>
4303 <li><tt>olt</tt>: ordered and less than </li>
4304 <li><tt>ole</tt>: ordered and less than or equal</li>
4305 <li><tt>one</tt>: ordered and not equal</li>
4306 <li><tt>ord</tt>: ordered (no nans)</li>
4307 <li><tt>ueq</tt>: unordered or equal</li>
4308 <li><tt>ugt</tt>: unordered or greater than </li>
4309 <li><tt>uge</tt>: unordered or greater than or equal</li>
4310 <li><tt>ult</tt>: unordered or less than </li>
4311 <li><tt>ule</tt>: unordered or less than or equal</li>
4312 <li><tt>une</tt>: unordered or not equal</li>
4313 <li><tt>uno</tt>: unordered (either nans)</li>
4314 <li><tt>true</tt>: no comparison, always returns true</li>
4315</ol>
4316<p><i>Ordered</i> means that neither operand is a QNAN while
4317<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4318<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4319either a <a href="#t_floating">floating point</a> type
4320or a <a href="#t_vector">vector</a> of floating point type.
4321They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4322<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4323<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4324according to the condition code given as <tt>cond</tt>.
4325If the operands are vectors, then the vectors are compared
4326element by element.
4327Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4328always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4329<ol>
4330 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4331 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4332 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4333 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4334 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4335 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4336 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4337 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4338 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4339 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4340 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4341 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4342 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4343 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4344 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4345 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4346 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4347 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4348 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4349 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4350 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4351 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4352 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4353 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4354 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4355 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4356 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4357 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4358</ol>
4359
4360<h5>Example:</h5>
4361<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4362 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4363 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4364 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4365</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4366
4367<p>Note that the code generator does not yet support vector types with
4368 the <tt>fcmp</tt> instruction.</p>
4369
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4370</div>
4371
4372<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4373<div class="doc_subsubsection">
4374 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4375</div>
4376<div class="doc_text">
4377<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4378<pre> &lt;result&gt; = vicmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4379</pre>
4380<h5>Overview:</h5>
4381<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4382element-wise comparison of its two integer vector operands.</p>
4383<h5>Arguments:</h5>
4384<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4385the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4386a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4387<ol>
4388 <li><tt>eq</tt>: equal</li>
4389 <li><tt>ne</tt>: not equal </li>
4390 <li><tt>ugt</tt>: unsigned greater than</li>
4391 <li><tt>uge</tt>: unsigned greater or equal</li>
4392 <li><tt>ult</tt>: unsigned less than</li>
4393 <li><tt>ule</tt>: unsigned less or equal</li>
4394 <li><tt>sgt</tt>: signed greater than</li>
4395 <li><tt>sge</tt>: signed greater or equal</li>
4396 <li><tt>slt</tt>: signed less than</li>
4397 <li><tt>sle</tt>: signed less or equal</li>
4398</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4399<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4400<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4401<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4402<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4403according to the condition code given as <tt>cond</tt>. The comparison yields a
4404<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4405identical type as the values being compared. The most significant bit in each
4406element is 1 if the element-wise comparison evaluates to true, and is 0
4407otherwise. All other bits of the result are undefined. The condition codes
4408are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4409instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4410
4411<h5>Example:</h5>
4412<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4413 &lt;result&gt; = vicmp eq &lt;2 x i32&gt; &lt; i32 4, i32 0&gt;, &lt; i32 5, i32 0&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4414 &lt;result&gt; = vicmp ult &lt;2 x i8 &gt; &lt; i8 1, i8 2&gt;, &lt; i8 2, i8 2 &gt; <i>; yields: result=&lt;2 x i8&gt; &lt; i8 -1, i8 0 &gt;</i>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4415</pre>
4416</div>
4417
4418<!-- _______________________________________________________________________ -->
4419<div class="doc_subsubsection">
4420 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4421</div>
4422<div class="doc_text">
4423<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4424<pre> &lt;result&gt; = vfcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt;</pre>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4425<h5>Overview:</h5>
4426<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4427element-wise comparison of its two floating point vector operands. The output
4428elements have the same width as the input elements.</p>
4429<h5>Arguments:</h5>
4430<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4431the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4432a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4433<ol>
4434 <li><tt>false</tt>: no comparison, always returns false</li>
4435 <li><tt>oeq</tt>: ordered and equal</li>
4436 <li><tt>ogt</tt>: ordered and greater than </li>
4437 <li><tt>oge</tt>: ordered and greater than or equal</li>
4438 <li><tt>olt</tt>: ordered and less than </li>
4439 <li><tt>ole</tt>: ordered and less than or equal</li>
4440 <li><tt>one</tt>: ordered and not equal</li>
4441 <li><tt>ord</tt>: ordered (no nans)</li>
4442 <li><tt>ueq</tt>: unordered or equal</li>
4443 <li><tt>ugt</tt>: unordered or greater than </li>
4444 <li><tt>uge</tt>: unordered or greater than or equal</li>
4445 <li><tt>ult</tt>: unordered or less than </li>
4446 <li><tt>ule</tt>: unordered or less than or equal</li>
4447 <li><tt>une</tt>: unordered or not equal</li>
4448 <li><tt>uno</tt>: unordered (either nans)</li>
4449 <li><tt>true</tt>: no comparison, always returns true</li>
4450</ol>
4451<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4452<a href="#t_floating">floating point</a> typed. They must also be identical
4453types.</p>
4454<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4455<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4456according to the condition code given as <tt>cond</tt>. The comparison yields a
4457<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4458an identical number of elements as the values being compared, and each element
4459having identical with to the width of the floating point elements. The most
4460significant bit in each element is 1 if the element-wise comparison evaluates to
4461true, and is 0 otherwise. All other bits of the result are undefined. The
4462condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4463<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4464
4465<h5>Example:</h5>
4466<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4467 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4468 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4469
4470 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4471 &lt;result&gt; = vfcmp ult &lt;2 x double&gt; &lt; double 1, double 2 &gt;, &lt; double 2, double 2&gt;
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4472</pre>
4473</div>
4474
4475<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4476<div class="doc_subsubsection">
4477 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4478</div>
4479
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4480<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4481
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4482<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4483
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4484<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4485<h5>Overview:</h5>
4486<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4487the SSA graph representing the function.</p>
4488<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4489
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4490<p>The type of the incoming values is specified with the first type
4491field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4492as arguments, with one pair for each predecessor basic block of the
4493current block. Only values of <a href="#t_firstclass">first class</a>
4494type may be used as the value arguments to the PHI node. Only labels
4495may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4496
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4497<p>There must be no non-phi instructions between the start of a basic
4498block and the PHI instructions: i.e. PHI instructions must be first in
4499a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4501<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4502
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4503<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4504specified by the pair corresponding to the predecessor basic block that executed
4505just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4506
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4507<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4508<pre>
4509Loop: ; Infinite loop that counts from 0 on up...
4510 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4511 %nextindvar = add i32 %indvar, 1
4512 br label %Loop
4513</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4514</div>
4515
4516<!-- _______________________________________________________________________ -->
4517<div class="doc_subsubsection">
4518 <a name="i_select">'<tt>select</tt>' Instruction</a>
4519</div>
4520
4521<div class="doc_text">
4522
4523<h5>Syntax:</h5>
4524
4525<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4526 &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>
4527
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4528 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4529</pre>
4530
4531<h5>Overview:</h5>
4532
4533<p>
4534The '<tt>select</tt>' instruction is used to choose one value based on a
4535condition, without branching.
4536</p>
4537
4538
4539<h5>Arguments:</h5>
4540
4541<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4542The '<tt>select</tt>' instruction requires an 'i1' value or
4543a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4544condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4545type. If the val1/val2 are vectors and
4546the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4547individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4548</p>
4549
4550<h5>Semantics:</h5>
4551
4552<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4553If the condition is an i1 and it evaluates to 1, the instruction returns the first
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4554value argument; otherwise, it returns the second value argument.
4555</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4556<p>
4557If the condition is a vector of i1, then the value arguments must
4558be vectors of the same size, and the selection is done element
4559by element.
4560</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4561
4562<h5>Example:</h5>
4563
4564<pre>
4565 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4566</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4567
4568<p>Note that the code generator does not yet support conditions
4569 with vector type.</p>
4570
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4571</div>
4572
4573
4574<!-- _______________________________________________________________________ -->
4575<div class="doc_subsubsection">
4576 <a name="i_call">'<tt>call</tt>' Instruction</a>
4577</div>
4578
4579<div class="doc_text">
4580
4581<h5>Syntax:</h5>
4582<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4583 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4584</pre>
4585
4586<h5>Overview:</h5>
4587
4588<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4589
4590<h5>Arguments:</h5>
4591
4592<p>This instruction requires several arguments:</p>
4593
4594<ol>
4595 <li>
4596 <p>The optional "tail" marker indicates whether the callee function accesses
4597 any allocas or varargs in the caller. If the "tail" marker is present, the
4598 function call is eligible for tail call optimization. Note that calls may
4599 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4600 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4601 </li>
4602 <li>
4603 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4604 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4605 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4606 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4607
4608 <li>
4609 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4610 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4611 and '<tt>inreg</tt>' attributes are valid here.</p>
4612 </li>
4613
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4614 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4615 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4616 the type of the return value. Functions that return no value are marked
4617 <tt><a href="#t_void">void</a></tt>.</p>
4618 </li>
4619 <li>
4620 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4621 value being invoked. The argument types must match the types implied by
4622 this signature. This type can be omitted if the function is not varargs
4623 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4624 </li>
4625 <li>
4626 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4627 be invoked. In most cases, this is a direct function invocation, but
4628 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4629 to function value.</p>
4630 </li>
4631 <li>
4632 <p>'<tt>function args</tt>': argument list whose types match the
4633 function signature argument types. All arguments must be of
4634 <a href="#t_firstclass">first class</a> type. If the function signature
4635 indicates the function accepts a variable number of arguments, the extra
4636 arguments can be specified.</p>
4637 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4638 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4639 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4640 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4641 '<tt>readnone</tt>' attributes are valid here.</p>
4642 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4643</ol>
4644
4645<h5>Semantics:</h5>
4646
4647<p>The '<tt>call</tt>' instruction is used to cause control flow to
4648transfer to a specified function, with its incoming arguments bound to
4649the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4650instruction in the called function, control flow continues with the
4651instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4652function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4653
4654<h5>Example:</h5>
4655
4656<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4657 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4658 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4659 %X = tail call i32 @foo() <i>; yields i32</i>
4660 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4661 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4662
4663 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4664 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4665 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4666 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4667 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4668 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4669</pre>
4670
4671</div>
4672
4673<!-- _______________________________________________________________________ -->
4674<div class="doc_subsubsection">
4675 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4676</div>
4677
4678<div class="doc_text">
4679
4680<h5>Syntax:</h5>
4681
4682<pre>
4683 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4684</pre>
4685
4686<h5>Overview:</h5>
4687
4688<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4689the "variable argument" area of a function call. It is used to implement the
4690<tt>va_arg</tt> macro in C.</p>
4691
4692<h5>Arguments:</h5>
4693
4694<p>This instruction takes a <tt>va_list*</tt> value and the type of
4695the argument. It returns a value of the specified argument type and
4696increments the <tt>va_list</tt> to point to the next argument. The
4697actual type of <tt>va_list</tt> is target specific.</p>
4698
4699<h5>Semantics:</h5>
4700
4701<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4702type from the specified <tt>va_list</tt> and causes the
4703<tt>va_list</tt> to point to the next argument. For more information,
4704see the variable argument handling <a href="#int_varargs">Intrinsic
4705Functions</a>.</p>
4706
4707<p>It is legal for this instruction to be called in a function which does not
4708take a variable number of arguments, for example, the <tt>vfprintf</tt>
4709function.</p>
4710
4711<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4712href="#intrinsics">intrinsic function</a> because it takes a type as an
4713argument.</p>
4714
4715<h5>Example:</h5>
4716
4717<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4718
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]4719<p>Note that the code generator does not yet fully support va_arg
4720 on many targets. Also, it does not currently support va_arg with
4721 aggregate types on any target.</p>
4722
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4723</div>
4724
4725<!-- *********************************************************************** -->
4726<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4727<!-- *********************************************************************** -->
4728
4729<div class="doc_text">
4730
4731<p>LLVM supports the notion of an "intrinsic function". These functions have
4732well known names and semantics and are required to follow certain restrictions.
4733Overall, these intrinsics represent an extension mechanism for the LLVM
4734language that does not require changing all of the transformations in LLVM when
4735adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4736
4737<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4738prefix is reserved in LLVM for intrinsic names; thus, function names may not
4739begin with this prefix. Intrinsic functions must always be external functions:
4740you cannot define the body of intrinsic functions. Intrinsic functions may
4741only be used in call or invoke instructions: it is illegal to take the address
4742of an intrinsic function. Additionally, because intrinsic functions are part
4743of the LLVM language, it is required if any are added that they be documented
4744here.</p>
4745
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4746<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4747a family of functions that perform the same operation but on different data
4748types. Because LLVM can represent over 8 million different integer types,
4749overloading is used commonly to allow an intrinsic function to operate on any
4750integer type. One or more of the argument types or the result type can be
4751overloaded to accept any integer type. Argument types may also be defined as
4752exactly matching a previous argument's type or the result type. This allows an
4753intrinsic function which accepts multiple arguments, but needs all of them to
4754be of the same type, to only be overloaded with respect to a single argument or
4755the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4756
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4757<p>Overloaded intrinsics will have the names of its overloaded argument types
4758encoded into its function name, each preceded by a period. Only those types
4759which are overloaded result in a name suffix. Arguments whose type is matched
4760against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4761take an integer of any width and returns an integer of exactly the same integer
4762width. This leads to a family of functions such as
4763<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4764Only one type, the return type, is overloaded, and only one type suffix is
4765required. Because the argument's type is matched against the return type, it
4766does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4767
4768<p>To learn how to add an intrinsic function, please see the
4769<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4770</p>
4771
4772</div>
4773
4774<!-- ======================================================================= -->
4775<div class="doc_subsection">
4776 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4777</div>
4778
4779<div class="doc_text">
4780
4781<p>Variable argument support is defined in LLVM with the <a
4782 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4783intrinsic functions. These functions are related to the similarly
4784named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4785
4786<p>All of these functions operate on arguments that use a
4787target-specific value type "<tt>va_list</tt>". The LLVM assembly
4788language reference manual does not define what this type is, so all
4789transformations should be prepared to handle these functions regardless of
4790the type used.</p>
4791
4792<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4793instruction and the variable argument handling intrinsic functions are
4794used.</p>
4795
4796<div class="doc_code">
4797<pre>
4798define i32 @test(i32 %X, ...) {
4799 ; Initialize variable argument processing
4800 %ap = alloca i8*
4801 %ap2 = bitcast i8** %ap to i8*
4802 call void @llvm.va_start(i8* %ap2)
4803
4804 ; Read a single integer argument
4805 %tmp = va_arg i8** %ap, i32
4806
4807 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4808 %aq = alloca i8*
4809 %aq2 = bitcast i8** %aq to i8*
4810 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4811 call void @llvm.va_end(i8* %aq2)
4812
4813 ; Stop processing of arguments.
4814 call void @llvm.va_end(i8* %ap2)
4815 ret i32 %tmp
4816}
4817
4818declare void @llvm.va_start(i8*)
4819declare void @llvm.va_copy(i8*, i8*)
4820declare void @llvm.va_end(i8*)
4821</pre>
4822</div>
4823
4824</div>
4825
4826<!-- _______________________________________________________________________ -->
4827<div class="doc_subsubsection">
4828 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4829</div>
4830
4831
4832<div class="doc_text">
4833<h5>Syntax:</h5>
4834<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4835<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4836<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4837<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4838href="#i_va_arg">va_arg</a></tt>.</p>
4839
4840<h5>Arguments:</h5>
4841
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4842<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4843
4844<h5>Semantics:</h5>
4845
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4846<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4847macro available in C. In a target-dependent way, it initializes the
4848<tt>va_list</tt> element to which the argument points, so that the next call to
4849<tt>va_arg</tt> will produce the first variable argument passed to the function.
4850Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4851last argument of the function as the compiler can figure that out.</p>
4852
4853</div>
4854
4855<!-- _______________________________________________________________________ -->
4856<div class="doc_subsubsection">
4857 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4858</div>
4859
4860<div class="doc_text">
4861<h5>Syntax:</h5>
4862<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4863<h5>Overview:</h5>
4864
4865<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4866which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4867or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4868
4869<h5>Arguments:</h5>
4870
4871<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4872
4873<h5>Semantics:</h5>
4874
4875<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4876macro available in C. In a target-dependent way, it destroys the
4877<tt>va_list</tt> element to which the argument points. Calls to <a
4878href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4879<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4880<tt>llvm.va_end</tt>.</p>
4881
4882</div>
4883
4884<!-- _______________________________________________________________________ -->
4885<div class="doc_subsubsection">
4886 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4887</div>
4888
4889<div class="doc_text">
4890
4891<h5>Syntax:</h5>
4892
4893<pre>
4894 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4895</pre>
4896
4897<h5>Overview:</h5>
4898
4899<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4900from the source argument list to the destination argument list.</p>
4901
4902<h5>Arguments:</h5>
4903
4904<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4905The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4906
4907
4908<h5>Semantics:</h5>
4909
4910<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4911macro available in C. In a target-dependent way, it copies the source
4912<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4913intrinsic is necessary because the <tt><a href="#int_va_start">
4914llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4915example, memory allocation.</p>
4916
4917</div>
4918
4919<!-- ======================================================================= -->
4920<div class="doc_subsection">
4921 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4922</div>
4923
4924<div class="doc_text">
4925
4926<p>
4927LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4928Collection</a> (GC) requires the implementation and generation of these
4929intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4930These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4931stack</a>, as well as garbage collector implementations that require <a
4932href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4933Front-ends for type-safe garbage collected languages should generate these
4934intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4935href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4936</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4937
4938<p>The garbage collection intrinsics only operate on objects in the generic
4939 address space (address space zero).</p>
4940
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4941</div>
4942
4943<!-- _______________________________________________________________________ -->
4944<div class="doc_subsubsection">
4945 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4946</div>
4947
4948<div class="doc_text">
4949
4950<h5>Syntax:</h5>
4951
4952<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4953 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4954</pre>
4955
4956<h5>Overview:</h5>
4957
4958<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4959the code generator, and allows some metadata to be associated with it.</p>
4960
4961<h5>Arguments:</h5>
4962
4963<p>The first argument specifies the address of a stack object that contains the
4964root pointer. The second pointer (which must be either a constant or a global
4965value address) contains the meta-data to be associated with the root.</p>
4966
4967<h5>Semantics:</h5>
4968
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4969<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4970location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4971the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4972intrinsic may only be used in a function which <a href="#gc">specifies a GC
4973algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4974
4975</div>
4976
4977
4978<!-- _______________________________________________________________________ -->
4979<div class="doc_subsubsection">
4980 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4981</div>
4982
4983<div class="doc_text">
4984
4985<h5>Syntax:</h5>
4986
4987<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4988 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4989</pre>
4990
4991<h5>Overview:</h5>
4992
4993<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4994locations, allowing garbage collector implementations that require read
4995barriers.</p>
4996
4997<h5>Arguments:</h5>
4998
4999<p>The second argument is the address to read from, which should be an address
5000allocated from the garbage collector. The first object is a pointer to the
5001start of the referenced object, if needed by the language runtime (otherwise
5002null).</p>
5003
5004<h5>Semantics:</h5>
5005
5006<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
5007instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5008garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5009may only be used in a function which <a href="#gc">specifies a GC
5010algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5011
5012</div>
5013
5014
5015<!-- _______________________________________________________________________ -->
5016<div class="doc_subsubsection">
5017 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5018</div>
5019
5020<div class="doc_text">
5021
5022<h5>Syntax:</h5>
5023
5024<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5025 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5026</pre>
5027
5028<h5>Overview:</h5>
5029
5030<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
5031locations, allowing garbage collector implementations that require write
5032barriers (such as generational or reference counting collectors).</p>
5033
5034<h5>Arguments:</h5>
5035
5036<p>The first argument is the reference to store, the second is the start of the
5037object to store it to, and the third is the address of the field of Obj to
5038store to. If the runtime does not require a pointer to the object, Obj may be
5039null.</p>
5040
5041<h5>Semantics:</h5>
5042
5043<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
5044instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5045garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5046may only be used in a function which <a href="#gc">specifies a GC
5047algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5048
5049</div>
5050
5051
5052
5053<!-- ======================================================================= -->
5054<div class="doc_subsection">
5055 <a name="int_codegen">Code Generator Intrinsics</a>
5056</div>
5057
5058<div class="doc_text">
5059<p>
5060These intrinsics are provided by LLVM to expose special features that may only
5061be implemented with code generator support.
5062</p>
5063
5064</div>
5065
5066<!-- _______________________________________________________________________ -->
5067<div class="doc_subsubsection">
5068 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5069</div>
5070
5071<div class="doc_text">
5072
5073<h5>Syntax:</h5>
5074<pre>
5075 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5076</pre>
5077
5078<h5>Overview:</h5>
5079
5080<p>
5081The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5082target-specific value indicating the return address of the current function
5083or one of its callers.
5084</p>
5085
5086<h5>Arguments:</h5>
5087
5088<p>
5089The argument to this intrinsic indicates which function to return the address
5090for. Zero indicates the calling function, one indicates its caller, etc. The
5091argument is <b>required</b> to be a constant integer value.
5092</p>
5093
5094<h5>Semantics:</h5>
5095
5096<p>
5097The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
5098the return address of the specified call frame, or zero if it cannot be
5099identified. The value returned by this intrinsic is likely to be incorrect or 0
5100for arguments other than zero, so it should only be used for debugging purposes.
5101</p>
5102
5103<p>
5104Note that calling this intrinsic does not prevent function inlining or other
5105aggressive transformations, so the value returned may not be that of the obvious
5106source-language caller.
5107</p>
5108</div>
5109
5110
5111<!-- _______________________________________________________________________ -->
5112<div class="doc_subsubsection">
5113 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5114</div>
5115
5116<div class="doc_text">
5117
5118<h5>Syntax:</h5>
5119<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5120 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5121</pre>
5122
5123<h5>Overview:</h5>
5124
5125<p>
5126The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5127target-specific frame pointer value for the specified stack frame.
5128</p>
5129
5130<h5>Arguments:</h5>
5131
5132<p>
5133The argument to this intrinsic indicates which function to return the frame
5134pointer for. Zero indicates the calling function, one indicates its caller,
5135etc. The argument is <b>required</b> to be a constant integer value.
5136</p>
5137
5138<h5>Semantics:</h5>
5139
5140<p>
5141The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
5142the frame address of the specified call frame, or zero if it cannot be
5143identified. The value returned by this intrinsic is likely to be incorrect or 0
5144for arguments other than zero, so it should only be used for debugging purposes.
5145</p>
5146
5147<p>
5148Note that calling this intrinsic does not prevent function inlining or other
5149aggressive transformations, so the value returned may not be that of the obvious
5150source-language caller.
5151</p>
5152</div>
5153
5154<!-- _______________________________________________________________________ -->
5155<div class="doc_subsubsection">
5156 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5157</div>
5158
5159<div class="doc_text">
5160
5161<h5>Syntax:</h5>
5162<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5163 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5164</pre>
5165
5166<h5>Overview:</h5>
5167
5168<p>
5169The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
5170the function stack, for use with <a href="#int_stackrestore">
5171<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
5172features like scoped automatic variable sized arrays in C99.
5173</p>
5174
5175<h5>Semantics:</h5>
5176
5177<p>
5178This intrinsic returns a opaque pointer value that can be passed to <a
5179href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
5180<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
5181<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
5182state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
5183practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
5184that were allocated after the <tt>llvm.stacksave</tt> was executed.
5185</p>
5186
5187</div>
5188
5189<!-- _______________________________________________________________________ -->
5190<div class="doc_subsubsection">
5191 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5192</div>
5193
5194<div class="doc_text">
5195
5196<h5>Syntax:</h5>
5197<pre>
5198 declare void @llvm.stackrestore(i8 * %ptr)
5199</pre>
5200
5201<h5>Overview:</h5>
5202
5203<p>
5204The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5205the function stack to the state it was in when the corresponding <a
5206href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
5207useful for implementing language features like scoped automatic variable sized
5208arrays in C99.
5209</p>
5210
5211<h5>Semantics:</h5>
5212
5213<p>
5214See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
5215</p>
5216
5217</div>
5218
5219
5220<!-- _______________________________________________________________________ -->
5221<div class="doc_subsubsection">
5222 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5223</div>
5224
5225<div class="doc_text">
5226
5227<h5>Syntax:</h5>
5228<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5229 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5230</pre>
5231
5232<h5>Overview:</h5>
5233
5234
5235<p>
5236The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
5237a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
5238no
5239effect on the behavior of the program but can change its performance
5240characteristics.
5241</p>
5242
5243<h5>Arguments:</h5>
5244
5245<p>
5246<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
5247determining if the fetch should be for a read (0) or write (1), and
5248<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5249locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
5250<tt>locality</tt> arguments must be constant integers.
5251</p>
5252
5253<h5>Semantics:</h5>
5254
5255<p>
5256This intrinsic does not modify the behavior of the program. In particular,
5257prefetches cannot trap and do not produce a value. On targets that support this
5258intrinsic, the prefetch can provide hints to the processor cache for better
5259performance.
5260</p>
5261
5262</div>
5263
5264<!-- _______________________________________________________________________ -->
5265<div class="doc_subsubsection">
5266 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5267</div>
5268
5269<div class="doc_text">
5270
5271<h5>Syntax:</h5>
5272<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5273 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5274</pre>
5275
5276<h5>Overview:</h5>
5277
5278
5279<p>
5280The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5281(PC) in a region of
5282code to simulators and other tools. The method is target specific, but it is
5283expected that the marker will use exported symbols to transmit the PC of the
5284marker.
5285The marker makes no guarantees that it will remain with any specific instruction
5286after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5287optimizations. The intended use is to be inserted after optimizations to allow
5288correlations of simulation runs.
5289</p>
5290
5291<h5>Arguments:</h5>
5292
5293<p>
5294<tt>id</tt> is a numerical id identifying the marker.
5295</p>
5296
5297<h5>Semantics:</h5>
5298
5299<p>
5300This intrinsic does not modify the behavior of the program. Backends that do not
5301support this intrinisic may ignore it.
5302</p>
5303
5304</div>
5305
5306<!-- _______________________________________________________________________ -->
5307<div class="doc_subsubsection">
5308 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5309</div>
5310
5311<div class="doc_text">
5312
5313<h5>Syntax:</h5>
5314<pre>
5315 declare i64 @llvm.readcyclecounter( )
5316</pre>
5317
5318<h5>Overview:</h5>
5319
5320
5321<p>
5322The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5323counter register (or similar low latency, high accuracy clocks) on those targets
5324that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5325As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5326should only be used for small timings.
5327</p>
5328
5329<h5>Semantics:</h5>
5330
5331<p>
5332When directly supported, reading the cycle counter should not modify any memory.
5333Implementations are allowed to either return a application specific value or a
5334system wide value. On backends without support, this is lowered to a constant 0.
5335</p>
5336
5337</div>
5338
5339<!-- ======================================================================= -->
5340<div class="doc_subsection">
5341 <a name="int_libc">Standard C Library Intrinsics</a>
5342</div>
5343
5344<div class="doc_text">
5345<p>
5346LLVM provides intrinsics for a few important standard C library functions.
5347These intrinsics allow source-language front-ends to pass information about the
5348alignment of the pointer arguments to the code generator, providing opportunity
5349for more efficient code generation.
5350</p>
5351
5352</div>
5353
5354<!-- _______________________________________________________________________ -->
5355<div class="doc_subsubsection">
5356 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5357</div>
5358
5359<div class="doc_text">
5360
5361<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5362<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5363width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5364<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5365 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5366 i8 &lt;len&gt;, i32 &lt;align&gt;)
5367 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5368 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5369 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5370 i32 &lt;len&gt;, i32 &lt;align&gt;)
5371 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5372 i64 &lt;len&gt;, i32 &lt;align&gt;)
5373</pre>
5374
5375<h5>Overview:</h5>
5376
5377<p>
5378The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5379location to the destination location.
5380</p>
5381
5382<p>
5383Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5384intrinsics do not return a value, and takes an extra alignment argument.
5385</p>
5386
5387<h5>Arguments:</h5>
5388
5389<p>
5390The first argument is a pointer to the destination, the second is a pointer to
5391the source. The third argument is an integer argument
5392specifying the number of bytes to copy, and the fourth argument is the alignment
5393of the source and destination locations.
5394</p>
5395
5396<p>
5397If the call to this intrinisic has an alignment value that is not 0 or 1, then
5398the caller guarantees that both the source and destination pointers are aligned
5399to that boundary.
5400</p>
5401
5402<h5>Semantics:</h5>
5403
5404<p>
5405The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5406location to the destination location, which are not allowed to overlap. It
5407copies "len" bytes of memory over. If the argument is known to be aligned to
5408some boundary, this can be specified as the fourth argument, otherwise it should
5409be set to 0 or 1.
5410</p>
5411</div>
5412
5413
5414<!-- _______________________________________________________________________ -->
5415<div class="doc_subsubsection">
5416 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5417</div>
5418
5419<div class="doc_text">
5420
5421<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5422<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5423width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5424<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5425 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5426 i8 &lt;len&gt;, i32 &lt;align&gt;)
5427 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5428 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5429 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5430 i32 &lt;len&gt;, i32 &lt;align&gt;)
5431 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5432 i64 &lt;len&gt;, i32 &lt;align&gt;)
5433</pre>
5434
5435<h5>Overview:</h5>
5436
5437<p>
5438The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5439location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5440'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5441</p>
5442
5443<p>
5444Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5445intrinsics do not return a value, and takes an extra alignment argument.
5446</p>
5447
5448<h5>Arguments:</h5>
5449
5450<p>
5451The first argument is a pointer to the destination, the second is a pointer to
5452the source. The third argument is an integer argument
5453specifying the number of bytes to copy, and the fourth argument is the alignment
5454of the source and destination locations.
5455</p>
5456
5457<p>
5458If the call to this intrinisic has an alignment value that is not 0 or 1, then
5459the caller guarantees that the source and destination pointers are aligned to
5460that boundary.
5461</p>
5462
5463<h5>Semantics:</h5>
5464
5465<p>
5466The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5467location to the destination location, which may overlap. It
5468copies "len" bytes of memory over. If the argument is known to be aligned to
5469some boundary, this can be specified as the fourth argument, otherwise it should
5470be set to 0 or 1.
5471</p>
5472</div>
5473
5474
5475<!-- _______________________________________________________________________ -->
5476<div class="doc_subsubsection">
5477 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5478</div>
5479
5480<div class="doc_text">
5481
5482<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5483<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5484width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5485<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5486 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5487 i8 &lt;len&gt;, i32 &lt;align&gt;)
5488 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5489 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5490 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5491 i32 &lt;len&gt;, i32 &lt;align&gt;)
5492 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5493 i64 &lt;len&gt;, i32 &lt;align&gt;)
5494</pre>
5495
5496<h5>Overview:</h5>
5497
5498<p>
5499The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5500byte value.
5501</p>
5502
5503<p>
5504Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5505does not return a value, and takes an extra alignment argument.
5506</p>
5507
5508<h5>Arguments:</h5>
5509
5510<p>
5511The first argument is a pointer to the destination to fill, the second is the
5512byte value to fill it with, the third argument is an integer
5513argument specifying the number of bytes to fill, and the fourth argument is the
5514known alignment of destination location.
5515</p>
5516
5517<p>
5518If the call to this intrinisic has an alignment value that is not 0 or 1, then
5519the caller guarantees that the destination pointer is aligned to that boundary.
5520</p>
5521
5522<h5>Semantics:</h5>
5523
5524<p>
5525The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5526the
5527destination location. If the argument is known to be aligned to some boundary,
5528this can be specified as the fourth argument, otherwise it should be set to 0 or
55291.
5530</p>
5531</div>
5532
5533
5534<!-- _______________________________________________________________________ -->
5535<div class="doc_subsubsection">
5536 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5537</div>
5538
5539<div class="doc_text">
5540
5541<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5542<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5543floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5544types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5545<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5546 declare float @llvm.sqrt.f32(float %Val)
5547 declare double @llvm.sqrt.f64(double %Val)
5548 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5549 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5550 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5551</pre>
5552
5553<h5>Overview:</h5>
5554
5555<p>
5556The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5557returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5558<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5559negative numbers other than -0.0 (which allows for better optimization, because
5560there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5561defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5562</p>
5563
5564<h5>Arguments:</h5>
5565
5566<p>
5567The argument and return value are floating point numbers of the same type.
5568</p>
5569
5570<h5>Semantics:</h5>
5571
5572<p>
5573This function returns the sqrt of the specified operand if it is a nonnegative
5574floating point number.
5575</p>
5576</div>
5577
5578<!-- _______________________________________________________________________ -->
5579<div class="doc_subsubsection">
5580 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5581</div>
5582
5583<div class="doc_text">
5584
5585<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5586<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5587floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5588types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5589<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5590 declare float @llvm.powi.f32(float %Val, i32 %power)
5591 declare double @llvm.powi.f64(double %Val, i32 %power)
5592 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5593 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5594 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5595</pre>
5596
5597<h5>Overview:</h5>
5598
5599<p>
5600The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5601specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5602multiplications is not defined. When a vector of floating point type is
5603used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5604</p>
5605
5606<h5>Arguments:</h5>
5607
5608<p>
5609The second argument is an integer power, and the first is a value to raise to
5610that power.
5611</p>
5612
5613<h5>Semantics:</h5>
5614
5615<p>
5616This function returns the first value raised to the second power with an
5617unspecified sequence of rounding operations.</p>
5618</div>
5619
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5620<!-- _______________________________________________________________________ -->
5621<div class="doc_subsubsection">
5622 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5623</div>
5624
5625<div class="doc_text">
5626
5627<h5>Syntax:</h5>
5628<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5629floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5630types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5631<pre>
5632 declare float @llvm.sin.f32(float %Val)
5633 declare double @llvm.sin.f64(double %Val)
5634 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5635 declare fp128 @llvm.sin.f128(fp128 %Val)
5636 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5637</pre>
5638
5639<h5>Overview:</h5>
5640
5641<p>
5642The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5643</p>
5644
5645<h5>Arguments:</h5>
5646
5647<p>
5648The argument and return value are floating point numbers of the same type.
5649</p>
5650
5651<h5>Semantics:</h5>
5652
5653<p>
5654This function returns the sine of the specified operand, returning the
5655same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5656conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5657</div>
5658
5659<!-- _______________________________________________________________________ -->
5660<div class="doc_subsubsection">
5661 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5662</div>
5663
5664<div class="doc_text">
5665
5666<h5>Syntax:</h5>
5667<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5668floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5669types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5670<pre>
5671 declare float @llvm.cos.f32(float %Val)
5672 declare double @llvm.cos.f64(double %Val)
5673 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5674 declare fp128 @llvm.cos.f128(fp128 %Val)
5675 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5676</pre>
5677
5678<h5>Overview:</h5>
5679
5680<p>
5681The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5682</p>
5683
5684<h5>Arguments:</h5>
5685
5686<p>
5687The argument and return value are floating point numbers of the same type.
5688</p>
5689
5690<h5>Semantics:</h5>
5691
5692<p>
5693This function returns the cosine of the specified operand, returning the
5694same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5695conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5696</div>
5697
5698<!-- _______________________________________________________________________ -->
5699<div class="doc_subsubsection">
5700 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5701</div>
5702
5703<div class="doc_text">
5704
5705<h5>Syntax:</h5>
5706<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5707floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5708types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5709<pre>
5710 declare float @llvm.pow.f32(float %Val, float %Power)
5711 declare double @llvm.pow.f64(double %Val, double %Power)
5712 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5713 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5714 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5715</pre>
5716
5717<h5>Overview:</h5>
5718
5719<p>
5720The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5721specified (positive or negative) power.
5722</p>
5723
5724<h5>Arguments:</h5>
5725
5726<p>
5727The second argument is a floating point power, and the first is a value to
5728raise to that power.
5729</p>
5730
5731<h5>Semantics:</h5>
5732
5733<p>
5734This function returns the first value raised to the second power,
5735returning the
5736same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5737conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5738</div>
5739
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5740
5741<!-- ======================================================================= -->
5742<div class="doc_subsection">
5743 <a name="int_manip">Bit Manipulation Intrinsics</a>
5744</div>
5745
5746<div class="doc_text">
5747<p>
5748LLVM provides intrinsics for a few important bit manipulation operations.
5749These allow efficient code generation for some algorithms.
5750</p>
5751
5752</div>
5753
5754<!-- _______________________________________________________________________ -->
5755<div class="doc_subsubsection">
5756 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5757</div>
5758
5759<div class="doc_text">
5760
5761<h5>Syntax:</h5>
5762<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5763type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5764<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5765 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5766 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5767 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5768</pre>
5769
5770<h5>Overview:</h5>
5771
5772<p>
5773The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5774values with an even number of bytes (positive multiple of 16 bits). These are
5775useful for performing operations on data that is not in the target's native
5776byte order.
5777</p>
5778
5779<h5>Semantics:</h5>
5780
5781<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5782The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5783and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5784intrinsic returns an i32 value that has the four bytes of the input i32
5785swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5786i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5787<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5788additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5789</p>
5790
5791</div>
5792
5793<!-- _______________________________________________________________________ -->
5794<div class="doc_subsubsection">
5795 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5796</div>
5797
5798<div class="doc_text">
5799
5800<h5>Syntax:</h5>
5801<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5802width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5803<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5804 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5805 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5806 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5807 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5808 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5809</pre>
5810
5811<h5>Overview:</h5>
5812
5813<p>
5814The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5815value.
5816</p>
5817
5818<h5>Arguments:</h5>
5819
5820<p>
5821The only argument is the value to be counted. The argument may be of any
5822integer type. The return type must match the argument type.
5823</p>
5824
5825<h5>Semantics:</h5>
5826
5827<p>
5828The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5829</p>
5830</div>
5831
5832<!-- _______________________________________________________________________ -->
5833<div class="doc_subsubsection">
5834 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5835</div>
5836
5837<div class="doc_text">
5838
5839<h5>Syntax:</h5>
5840<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5841integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5842<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5843 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5844 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5845 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5846 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5847 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5848</pre>
5849
5850<h5>Overview:</h5>
5851
5852<p>
5853The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5854leading zeros in a variable.
5855</p>
5856
5857<h5>Arguments:</h5>
5858
5859<p>
5860The only argument is the value to be counted. The argument may be of any
5861integer type. The return type must match the argument type.
5862</p>
5863
5864<h5>Semantics:</h5>
5865
5866<p>
5867The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5868in a variable. If the src == 0 then the result is the size in bits of the type
5869of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5870</p>
5871</div>
5872
5873
5874
5875<!-- _______________________________________________________________________ -->
5876<div class="doc_subsubsection">
5877 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5878</div>
5879
5880<div class="doc_text">
5881
5882<h5>Syntax:</h5>
5883<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5884integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5885<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5886 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5887 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5888 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5889 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5890 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5891</pre>
5892
5893<h5>Overview:</h5>
5894
5895<p>
5896The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5897trailing zeros.
5898</p>
5899
5900<h5>Arguments:</h5>
5901
5902<p>
5903The only argument is the value to be counted. The argument may be of any
5904integer type. The return type must match the argument type.
5905</p>
5906
5907<h5>Semantics:</h5>
5908
5909<p>
5910The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5911in a variable. If the src == 0 then the result is the size in bits of the type
5912of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5913</p>
5914</div>
5915
5916<!-- _______________________________________________________________________ -->
5917<div class="doc_subsubsection">
5918 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5919</div>
5920
5921<div class="doc_text">
5922
5923<h5>Syntax:</h5>
5924<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5925on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5926<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5927 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5928 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5929</pre>
5930
5931<h5>Overview:</h5>
5932<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5933range of bits from an integer value and returns them in the same bit width as
5934the original value.</p>
5935
5936<h5>Arguments:</h5>
5937<p>The first argument, <tt>%val</tt> and the result may be integer types of
5938any bit width but they must have the same bit width. The second and third
5939arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5940
5941<h5>Semantics:</h5>
5942<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5943of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5944<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5945operates in forward mode.</p>
5946<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5947right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5948only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5949<ol>
5950 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5951 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5952 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5953 to determine the number of bits to retain.</li>
5954 <li>A mask of the retained bits is created by shifting a -1 value.</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5955 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5956</ol>
5957<p>In reverse mode, a similar computation is made except that the bits are
5958returned in the reverse order. So, for example, if <tt>X</tt> has the value
5959<tt>i16 0x0ACF (101011001111)</tt> and we apply
5960<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5961<tt>i16 0x0026 (000000100110)</tt>.</p>
5962</div>
5963
5964<div class="doc_subsubsection">
5965 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5966</div>
5967
5968<div class="doc_text">
5969
5970<h5>Syntax:</h5>
5971<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5972on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5973<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5974 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5975 declare i29 @llvm.part.set.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5976</pre>
5977
5978<h5>Overview:</h5>
5979<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5980of bits in an integer value with another integer value. It returns the integer
5981with the replaced bits.</p>
5982
5983<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5984<p>The first argument, <tt>%val</tt>, and the result may be integer types of
5985any bit width, but they must have the same bit width. <tt>%val</tt> is the value
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5986whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5987integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5988type since they specify only a bit index.</p>
5989
5990<h5>Semantics:</h5>
5991<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5992of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5993<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5994operates in forward mode.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5995
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5996<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5997truncating it down to the size of the replacement area or zero extending it
5998up to that size.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5999
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6000<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
6001are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
6002in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6003to the <tt>%hi</tt>th bit.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6004
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6005<p>In reverse mode, a similar computation is made except that the bits are
6006reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6007<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6008
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6009<h5>Examples:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6010
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6011<pre>
6012 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
6013 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
6014 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
6015 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
6016 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
6017</pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6018
6019</div>
6020
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6021<!-- ======================================================================= -->
6022<div class="doc_subsection">
6023 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6024</div>
6025
6026<div class="doc_text">
6027<p>
6028LLVM provides intrinsics for some arithmetic with overflow operations.
6029</p>
6030
6031</div>
6032
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6033<!-- _______________________________________________________________________ -->
6034<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6035 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6036</div>
6037
6038<div class="doc_text">
6039
6040<h5>Syntax:</h5>
6041
6042<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6043on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6044
6045<pre>
6046 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6047 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6048 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6049</pre>
6050
6051<h5>Overview:</h5>
6052
6053<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
6054a signed addition of the two arguments, and indicate whether an overflow
6055occurred during the signed summation.</p>
6056
6057<h5>Arguments:</h5>
6058
6059<p>The arguments (%a and %b) and the first element of the result structure may
6060be of integer types of any bit width, but they must have the same bit width. The
6061second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6062and <tt>%b</tt> are the two values that will undergo signed addition.</p>
6063
6064<h5>Semantics:</h5>
6065
6066<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
6067a signed addition of the two variables. They return a structure &mdash; the
6068first element of which is the signed summation, and the second element of which
6069is a bit specifying if the signed summation resulted in an overflow.</p>
6070
6071<h5>Examples:</h5>
6072<pre>
6073 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6074 %sum = extractvalue {i32, i1} %res, 0
6075 %obit = extractvalue {i32, i1} %res, 1
6076 br i1 %obit, label %overflow, label %normal
6077</pre>
6078
6079</div>
6080
6081<!-- _______________________________________________________________________ -->
6082<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6083 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6084</div>
6085
6086<div class="doc_text">
6087
6088<h5>Syntax:</h5>
6089
6090<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6091on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6092
6093<pre>
6094 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6095 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6096 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6097</pre>
6098
6099<h5>Overview:</h5>
6100
6101<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6102an unsigned addition of the two arguments, and indicate whether a carry occurred
6103during the unsigned summation.</p>
6104
6105<h5>Arguments:</h5>
6106
6107<p>The arguments (%a and %b) and the first element of the result structure may
6108be of integer types of any bit width, but they must have the same bit width. The
6109second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6110and <tt>%b</tt> are the two values that will undergo unsigned addition.</p>
6111
6112<h5>Semantics:</h5>
6113
6114<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6115an unsigned addition of the two arguments. They return a structure &mdash; the
6116first element of which is the sum, and the second element of which is a bit
6117specifying if the unsigned summation resulted in a carry.</p>
6118
6119<h5>Examples:</h5>
6120<pre>
6121 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6122 %sum = extractvalue {i32, i1} %res, 0
6123 %obit = extractvalue {i32, i1} %res, 1
6124 br i1 %obit, label %carry, label %normal
6125</pre>
6126
6127</div>
6128
6129<!-- _______________________________________________________________________ -->
6130<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6131 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6132</div>
6133
6134<div class="doc_text">
6135
6136<h5>Syntax:</h5>
6137
6138<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6139on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6140
6141<pre>
6142 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6143 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6144 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6145</pre>
6146
6147<h5>Overview:</h5>
6148
6149<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6150a signed subtraction of the two arguments, and indicate whether an overflow
6151occurred during the signed subtraction.</p>
6152
6153<h5>Arguments:</h5>
6154
6155<p>The arguments (%a and %b) and the first element of the result structure may
6156be of integer types of any bit width, but they must have the same bit width. The
6157second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6158and <tt>%b</tt> are the two values that will undergo signed subtraction.</p>
6159
6160<h5>Semantics:</h5>
6161
6162<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6163a signed subtraction of the two arguments. They return a structure &mdash; the
6164first element of which is the subtraction, and the second element of which is a bit
6165specifying if the signed subtraction resulted in an overflow.</p>
6166
6167<h5>Examples:</h5>
6168<pre>
6169 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6170 %sum = extractvalue {i32, i1} %res, 0
6171 %obit = extractvalue {i32, i1} %res, 1
6172 br i1 %obit, label %overflow, label %normal
6173</pre>
6174
6175</div>
6176
6177<!-- _______________________________________________________________________ -->
6178<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6179 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6180</div>
6181
6182<div class="doc_text">
6183
6184<h5>Syntax:</h5>
6185
6186<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6187on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6188
6189<pre>
6190 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6191 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6192 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6193</pre>
6194
6195<h5>Overview:</h5>
6196
6197<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6198an unsigned subtraction of the two arguments, and indicate whether an overflow
6199occurred during the unsigned subtraction.</p>
6200
6201<h5>Arguments:</h5>
6202
6203<p>The arguments (%a and %b) and the first element of the result structure may
6204be of integer types of any bit width, but they must have the same bit width. The
6205second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6206and <tt>%b</tt> are the two values that will undergo unsigned subtraction.</p>
6207
6208<h5>Semantics:</h5>
6209
6210<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6211an unsigned subtraction of the two arguments. They return a structure &mdash; the
6212first element of which is the subtraction, and the second element of which is a bit
6213specifying if the unsigned subtraction resulted in an overflow.</p>
6214
6215<h5>Examples:</h5>
6216<pre>
6217 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6218 %sum = extractvalue {i32, i1} %res, 0
6219 %obit = extractvalue {i32, i1} %res, 1
6220 br i1 %obit, label %overflow, label %normal
6221</pre>
6222
6223</div>
6224
6225<!-- _______________________________________________________________________ -->
6226<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6227 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6228</div>
6229
6230<div class="doc_text">
6231
6232<h5>Syntax:</h5>
6233
6234<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6235on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6236
6237<pre>
6238 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6239 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6240 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6241</pre>
6242
6243<h5>Overview:</h5>
6244
6245<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6246a signed multiplication of the two arguments, and indicate whether an overflow
6247occurred during the signed multiplication.</p>
6248
6249<h5>Arguments:</h5>
6250
6251<p>The arguments (%a and %b) and the first element of the result structure may
6252be of integer types of any bit width, but they must have the same bit width. The
6253second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6254and <tt>%b</tt> are the two values that will undergo signed multiplication.</p>
6255
6256<h5>Semantics:</h5>
6257
6258<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6259a signed multiplication of the two arguments. They return a structure &mdash;
6260the first element of which is the multiplication, and the second element of
6261which is a bit specifying if the signed multiplication resulted in an
6262overflow.</p>
6263
6264<h5>Examples:</h5>
6265<pre>
6266 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6267 %sum = extractvalue {i32, i1} %res, 0
6268 %obit = extractvalue {i32, i1} %res, 1
6269 br i1 %obit, label %overflow, label %normal
6270</pre>
6271
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6272</div>
6273
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6274<!-- _______________________________________________________________________ -->
6275<div class="doc_subsubsection">
6276 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6277</div>
6278
6279<div class="doc_text">
6280
6281<h5>Syntax:</h5>
6282
6283<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
6284on any integer bit width.</p>
6285
6286<pre>
6287 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6288 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6289 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6290</pre>
6291
6292<h5>Overview:</h5>
6293
6294<p><i><b>Warning:</b> '<tt>llvm.umul.with.overflow</tt>' is badly broken. It is
6295actively being fixed, but it should not currently be used!</i></p>
6296
6297<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6298a unsigned multiplication of the two arguments, and indicate whether an overflow
6299occurred during the unsigned multiplication.</p>
6300
6301<h5>Arguments:</h5>
6302
6303<p>The arguments (%a and %b) and the first element of the result structure may
6304be of integer types of any bit width, but they must have the same bit width. The
6305second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6306and <tt>%b</tt> are the two values that will undergo unsigned
6307multiplication.</p>
6308
6309<h5>Semantics:</h5>
6310
6311<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6312an unsigned multiplication of the two arguments. They return a structure &mdash;
6313the first element of which is the multiplication, and the second element of
6314which is a bit specifying if the unsigned multiplication resulted in an
6315overflow.</p>
6316
6317<h5>Examples:</h5>
6318<pre>
6319 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6320 %sum = extractvalue {i32, i1} %res, 0
6321 %obit = extractvalue {i32, i1} %res, 1
6322 br i1 %obit, label %overflow, label %normal
6323</pre>
6324
6325</div>
6326
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6327<!-- ======================================================================= -->
6328<div class="doc_subsection">
6329 <a name="int_debugger">Debugger Intrinsics</a>
6330</div>
6331
6332<div class="doc_text">
6333<p>
6334The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
6335are described in the <a
6336href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
6337Debugging</a> document.
6338</p>
6339</div>
6340
6341
6342<!-- ======================================================================= -->
6343<div class="doc_subsection">
6344 <a name="int_eh">Exception Handling Intrinsics</a>
6345</div>
6346
6347<div class="doc_text">
6348<p> The LLVM exception handling intrinsics (which all start with
6349<tt>llvm.eh.</tt> prefix), are described in the <a
6350href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6351Handling</a> document. </p>
6352</div>
6353
6354<!-- ======================================================================= -->
6355<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6356 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6357</div>
6358
6359<div class="doc_text">
6360<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6361 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6362 the <tt>nest</tt> attribute, from a function. The result is a callable
6363 function pointer lacking the nest parameter - the caller does not need
6364 to provide a value for it. Instead, the value to use is stored in
6365 advance in a "trampoline", a block of memory usually allocated
6366 on the stack, which also contains code to splice the nest value into the
6367 argument list. This is used to implement the GCC nested function address
6368 extension.
6369</p>
6370<p>
6371 For example, if the function is
6372 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]6373 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as follows:</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6374<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6375 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6376 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6377 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6378 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6379</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]6380 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6381 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6382</div>
6383
6384<!-- _______________________________________________________________________ -->
6385<div class="doc_subsubsection">
6386 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6387</div>
6388<div class="doc_text">
6389<h5>Syntax:</h5>
6390<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6391declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6392</pre>
6393<h5>Overview:</h5>
6394<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6395 This fills the memory pointed to by <tt>tramp</tt> with code
6396 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6397</p>
6398<h5>Arguments:</h5>
6399<p>
6400 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6401 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
6402 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]6403 intrinsic. Note that the size and the alignment are target-specific - LLVM
6404 currently provides no portable way of determining them, so a front-end that
6405 generates this intrinsic needs to have some target-specific knowledge.
6406 The <tt>func</tt> argument must hold a function bitcast to an <tt>i8*</tt>.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6407</p>
6408<h5>Semantics:</h5>
6409<p>
6410 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6411 dependent code, turning it into a function. A pointer to this function is
6412 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6413 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6414 before being called. The new function's signature is the same as that of
6415 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
6416 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
6417 of pointer type. Calling the new function is equivalent to calling
6418 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
6419 missing <tt>nest</tt> argument. If, after calling
6420 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
6421 modified, then the effect of any later call to the returned function pointer is
6422 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6423</p>
6424</div>
6425
6426<!-- ======================================================================= -->
6427<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6428 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6429</div>
6430
6431<div class="doc_text">
6432<p>
6433 These intrinsic functions expand the "universal IR" of LLVM to represent
6434 hardware constructs for atomic operations and memory synchronization. This
6435 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]6436 is aimed at a low enough level to allow any programming models or APIs
6437 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6438 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
6439 hardware behavior. Just as hardware provides a "universal IR" for source
6440 languages, it also provides a starting point for developing a "universal"
6441 atomic operation and synchronization IR.
6442</p>
6443<p>
6444 These do <em>not</em> form an API such as high-level threading libraries,
6445 software transaction memory systems, atomic primitives, and intrinsic
6446 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6447 application libraries. The hardware interface provided by LLVM should allow
6448 a clean implementation of all of these APIs and parallel programming models.
6449 No one model or paradigm should be selected above others unless the hardware
6450 itself ubiquitously does so.
6451
6452</p>
6453</div>
6454
6455<!-- _______________________________________________________________________ -->
6456<div class="doc_subsubsection">
6457 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6458</div>
6459<div class="doc_text">
6460<h5>Syntax:</h5>
6461<pre>
6462declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
6463i1 &lt;device&gt; )
6464
6465</pre>
6466<h5>Overview:</h5>
6467<p>
6468 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6469 specific pairs of memory access types.
6470</p>
6471<h5>Arguments:</h5>
6472<p>
6473 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6474 The first four arguments enables a specific barrier as listed below. The fith
6475 argument specifies that the barrier applies to io or device or uncached memory.
6476
6477</p>
6478 <ul>
6479 <li><tt>ll</tt>: load-load barrier</li>
6480 <li><tt>ls</tt>: load-store barrier</li>
6481 <li><tt>sl</tt>: store-load barrier</li>
6482 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6483 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6484 </ul>
6485<h5>Semantics:</h5>
6486<p>
6487 This intrinsic causes the system to enforce some ordering constraints upon
6488 the loads and stores of the program. This barrier does not indicate
6489 <em>when</em> any events will occur, it only enforces an <em>order</em> in
6490 which they occur. For any of the specified pairs of load and store operations
6491 (f.ex. load-load, or store-load), all of the first operations preceding the
6492 barrier will complete before any of the second operations succeeding the
6493 barrier begin. Specifically the semantics for each pairing is as follows:
6494</p>
6495 <ul>
6496 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6497 after the barrier begins.</li>
6498
6499 <li><tt>ls</tt>: All loads before the barrier must complete before any
6500 store after the barrier begins.</li>
6501 <li><tt>ss</tt>: All stores before the barrier must complete before any
6502 store after the barrier begins.</li>
6503 <li><tt>sl</tt>: All stores before the barrier must complete before any
6504 load after the barrier begins.</li>
6505 </ul>
6506<p>
6507 These semantics are applied with a logical "and" behavior when more than one
6508 is enabled in a single memory barrier intrinsic.
6509</p>
6510<p>
6511 Backends may implement stronger barriers than those requested when they do not
6512 support as fine grained a barrier as requested. Some architectures do not
6513 need all types of barriers and on such architectures, these become noops.
6514</p>
6515<h5>Example:</h5>
6516<pre>
6517%ptr = malloc i32
6518 store i32 4, %ptr
6519
6520%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6521 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6522 <i>; guarantee the above finishes</i>
6523 store i32 8, %ptr <i>; before this begins</i>
6524</pre>
6525</div>
6526
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6527<!-- _______________________________________________________________________ -->
6528<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6529 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6530</div>
6531<div class="doc_text">
6532<h5>Syntax:</h5>
6533<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6534 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6535 any integer bit width and for different address spaces. Not all targets
6536 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6537
6538<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6539declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6540declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6541declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6542declare i64 @llvm.atomic.cmp.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6543
6544</pre>
6545<h5>Overview:</h5>
6546<p>
6547 This loads a value in memory and compares it to a given value. If they are
6548 equal, it stores a new value into the memory.
6549</p>
6550<h5>Arguments:</h5>
6551<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6552 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6553 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6554 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6555 this integer type. While any bit width integer may be used, targets may only
6556 lower representations they support in hardware.
6557
6558</p>
6559<h5>Semantics:</h5>
6560<p>
6561 This entire intrinsic must be executed atomically. It first loads the value
6562 in memory pointed to by <tt>ptr</tt> and compares it with the value
6563 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
6564 loaded value is yielded in all cases. This provides the equivalent of an
6565 atomic compare-and-swap operation within the SSA framework.
6566</p>
6567<h5>Examples:</h5>
6568
6569<pre>
6570%ptr = malloc i32
6571 store i32 4, %ptr
6572
6573%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6574%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6575 <i>; yields {i32}:result1 = 4</i>
6576%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6577%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6578
6579%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6580%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6581 <i>; yields {i32}:result2 = 8</i>
6582%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6583
6584%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6585</pre>
6586</div>
6587
6588<!-- _______________________________________________________________________ -->
6589<div class="doc_subsubsection">
6590 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6591</div>
6592<div class="doc_text">
6593<h5>Syntax:</h5>
6594
6595<p>
6596 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6597 integer bit width. Not all targets support all bit widths however.</p>
6598<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6599declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6600declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6601declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6602declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6603
6604</pre>
6605<h5>Overview:</h5>
6606<p>
6607 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6608 the value from memory. It then stores the value in <tt>val</tt> in the memory
6609 at <tt>ptr</tt>.
6610</p>
6611<h5>Arguments:</h5>
6612
6613<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6614 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6615 <tt>val</tt> argument and the result must be integers of the same bit width.
6616 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6617 integer type. The targets may only lower integer representations they
6618 support.
6619</p>
6620<h5>Semantics:</h5>
6621<p>
6622 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6623 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6624 equivalent of an atomic swap operation within the SSA framework.
6625
6626</p>
6627<h5>Examples:</h5>
6628<pre>
6629%ptr = malloc i32
6630 store i32 4, %ptr
6631
6632%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6633%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6634 <i>; yields {i32}:result1 = 4</i>
6635%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6636%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6637
6638%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6639%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6640 <i>; yields {i32}:result2 = 8</i>
6641
6642%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6643%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6644</pre>
6645</div>
6646
6647<!-- _______________________________________________________________________ -->
6648<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6649 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6650
6651</div>
6652<div class="doc_text">
6653<h5>Syntax:</h5>
6654<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6655 This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on any
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6656 integer bit width. Not all targets support all bit widths however.</p>
6657<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6658declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6659declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6660declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6661declare i64 @llvm.atomic.load.add.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6662
6663</pre>
6664<h5>Overview:</h5>
6665<p>
6666 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6667 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6668</p>
6669<h5>Arguments:</h5>
6670<p>
6671
6672 The intrinsic takes two arguments, the first a pointer to an integer value
6673 and the second an integer value. The result is also an integer value. These
6674 integer types can have any bit width, but they must all have the same bit
6675 width. The targets may only lower integer representations they support.
6676</p>
6677<h5>Semantics:</h5>
6678<p>
6679 This intrinsic does a series of operations atomically. It first loads the
6680 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6681 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6682</p>
6683
6684<h5>Examples:</h5>
6685<pre>
6686%ptr = malloc i32
6687 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6688%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6689 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6690%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6691 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6692%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6693 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6694%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6695</pre>
6696</div>
6697
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6698<!-- _______________________________________________________________________ -->
6699<div class="doc_subsubsection">
6700 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6701
6702</div>
6703<div class="doc_text">
6704<h5>Syntax:</h5>
6705<p>
6706 This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6707 any integer bit width and for different address spaces. Not all targets
6708 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6709<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6710declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6711declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6712declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6713declare i64 @llvm.atomic.load.sub.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6714
6715</pre>
6716<h5>Overview:</h5>
6717<p>
6718 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6719 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6720</p>
6721<h5>Arguments:</h5>
6722<p>
6723
6724 The intrinsic takes two arguments, the first a pointer to an integer value
6725 and the second an integer value. The result is also an integer value. These
6726 integer types can have any bit width, but they must all have the same bit
6727 width. The targets may only lower integer representations they support.
6728</p>
6729<h5>Semantics:</h5>
6730<p>
6731 This intrinsic does a series of operations atomically. It first loads the
6732 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6733 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6734</p>
6735
6736<h5>Examples:</h5>
6737<pre>
6738%ptr = malloc i32
6739 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6740%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6741 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6742%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6743 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6744%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6745 <i>; yields {i32}:result3 = 2</i>
6746%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6747</pre>
6748</div>
6749
6750<!-- _______________________________________________________________________ -->
6751<div class="doc_subsubsection">
6752 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6753 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6754 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6755 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6756
6757</div>
6758<div class="doc_text">
6759<h5>Syntax:</h5>
6760<p>
6761 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6762 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6763 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6764 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6765<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6766declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6767declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6768declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6769declare i64 @llvm.atomic.load.and.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6770
6771</pre>
6772
6773<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6774declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6775declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6776declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6777declare i64 @llvm.atomic.load.or.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6778
6779</pre>
6780
6781<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6782declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6783declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6784declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6785declare i64 @llvm.atomic.load.nand.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6786
6787</pre>
6788
6789<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6790declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6791declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6792declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6793declare i64 @llvm.atomic.load.xor.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6794
6795</pre>
6796<h5>Overview:</h5>
6797<p>
6798 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6799 the value stored in memory at <tt>ptr</tt>. It yields the original value
6800 at <tt>ptr</tt>.
6801</p>
6802<h5>Arguments:</h5>
6803<p>
6804
6805 These intrinsics take two arguments, the first a pointer to an integer value
6806 and the second an integer value. The result is also an integer value. These
6807 integer types can have any bit width, but they must all have the same bit
6808 width. The targets may only lower integer representations they support.
6809</p>
6810<h5>Semantics:</h5>
6811<p>
6812 These intrinsics does a series of operations atomically. They first load the
6813 value stored at <tt>ptr</tt>. They then do the bitwise operation
6814 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6815 value stored at <tt>ptr</tt>.
6816</p>
6817
6818<h5>Examples:</h5>
6819<pre>
6820%ptr = malloc i32
6821 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6822%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6823 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6824%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6825 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6826%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6827 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6828%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6829 <i>; yields {i32}:result3 = FF</i>
6830%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6831</pre>
6832</div>
6833
6834
6835<!-- _______________________________________________________________________ -->
6836<div class="doc_subsubsection">
6837 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6838 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6839 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6840 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6841
6842</div>
6843<div class="doc_text">
6844<h5>Syntax:</h5>
6845<p>
6846 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6847 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6848 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6849 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6850 support all bit widths however.</p>
6851<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6852declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6853declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6854declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6855declare i64 @llvm.atomic.load.max.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6856
6857</pre>
6858
6859<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6860declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6861declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6862declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6863declare i64 @llvm.atomic.load.min.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6864
6865</pre>
6866
6867<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6868declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6869declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6870declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6871declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6872
6873</pre>
6874
6875<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6876declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6877declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6878declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6879declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6880
6881</pre>
6882<h5>Overview:</h5>
6883<p>
6884 These intrinsics takes the signed or unsigned minimum or maximum of
6885 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6886 original value at <tt>ptr</tt>.
6887</p>
6888<h5>Arguments:</h5>
6889<p>
6890
6891 These intrinsics take two arguments, the first a pointer to an integer value
6892 and the second an integer value. The result is also an integer value. These
6893 integer types can have any bit width, but they must all have the same bit
6894 width. The targets may only lower integer representations they support.
6895</p>
6896<h5>Semantics:</h5>
6897<p>
6898 These intrinsics does a series of operations atomically. They first load the
6899 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6900 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6901 the original value stored at <tt>ptr</tt>.
6902</p>
6903
6904<h5>Examples:</h5>
6905<pre>
6906%ptr = malloc i32
6907 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6908%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6909 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6910%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6911 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6912%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6913 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6914%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6915 <i>; yields {i32}:result3 = 8</i>
6916%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6917</pre>
6918</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6919
6920<!-- ======================================================================= -->
6921<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6922 <a name="int_general">General Intrinsics</a>
6923</div>
6924
6925<div class="doc_text">
6926<p> This class of intrinsics is designed to be generic and has
6927no specific purpose. </p>
6928</div>
6929
6930<!-- _______________________________________________________________________ -->
6931<div class="doc_subsubsection">
6932 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6933</div>
6934
6935<div class="doc_text">
6936
6937<h5>Syntax:</h5>
6938<pre>
6939 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6940</pre>
6941
6942<h5>Overview:</h5>
6943
6944<p>
6945The '<tt>llvm.var.annotation</tt>' intrinsic
6946</p>
6947
6948<h5>Arguments:</h5>
6949
6950<p>
6951The first argument is a pointer to a value, the second is a pointer to a
6952global string, the third is a pointer to a global string which is the source
6953file name, and the last argument is the line number.
6954</p>
6955
6956<h5>Semantics:</h5>
6957
6958<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6959This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6960This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6961annotations. These have no other defined use, they are ignored by code
6962generation and optimization.
6963</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6964</div>
6965
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6966<!-- _______________________________________________________________________ -->
6967<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6968 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6969</div>
6970
6971<div class="doc_text">
6972
6973<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6974<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6975any integer bit width.
6976</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6977<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6978 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6979 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6980 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6981 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6982 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6983</pre>
6984
6985<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6986
6987<p>
6988The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6989</p>
6990
6991<h5>Arguments:</h5>
6992
6993<p>
6994The first argument is an integer value (result of some expression),
6995the second is a pointer to a global string, the third is a pointer to a global
6996string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6997It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6998</p>
6999
7000<h5>Semantics:</h5>
7001
7002<p>
7003This intrinsic allows annotations to be put on arbitrary expressions
7004with arbitrary strings. This can be useful for special purpose optimizations
7005that want to look for these annotations. These have no other defined use, they
7006are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]7007</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7008</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7009
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7010<!-- _______________________________________________________________________ -->
7011<div class="doc_subsubsection">
7012 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7013</div>
7014
7015<div class="doc_text">
7016
7017<h5>Syntax:</h5>
7018<pre>
7019 declare void @llvm.trap()
7020</pre>
7021
7022<h5>Overview:</h5>
7023
7024<p>
7025The '<tt>llvm.trap</tt>' intrinsic
7026</p>
7027
7028<h5>Arguments:</h5>
7029
7030<p>
7031None
7032</p>
7033
7034<h5>Semantics:</h5>
7035
7036<p>
7037This intrinsics is lowered to the target dependent trap instruction. If the
7038target does not have a trap instruction, this intrinsic will be lowered to the
7039call of the abort() function.
7040</p>
7041</div>
7042
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7043<!-- _______________________________________________________________________ -->
7044<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7045 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7046</div>
7047<div class="doc_text">
7048<h5>Syntax:</h5>
7049<pre>
7050declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
7051
7052</pre>
7053<h5>Overview:</h5>
7054<p>
7055 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
7056 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
7057 it is placed on the stack before local variables.
7058</p>
7059<h5>Arguments:</h5>
7060<p>
7061 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
7062 first argument is the value loaded from the stack guard
7063 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
7064 has enough space to hold the value of the guard.
7065</p>
7066<h5>Semantics:</h5>
7067<p>
7068 This intrinsic causes the prologue/epilogue inserter to force the position of
7069 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7070 stack. This is to ensure that if a local variable on the stack is overwritten,
7071 it will destroy the value of the guard. When the function exits, the guard on
7072 the stack is checked against the original guard. If they're different, then
7073 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
7074</p>
7075</div>
7076
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7077<!-- *********************************************************************** -->
7078<hr>
7079<address>
7080 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7081 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7082 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7083 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7084
7085 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7086 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7087 Last modified: $Date$
7088</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7089
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7090</body>
7091</html>