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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 117f43894909ceafe7c390717c70add4c6449b33 / . / 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
2386<h5>Example:</h5>
2387<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2388 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2389 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2390 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2391 unwind label %TestCleanup <i>; {i32}:retval set</i>
2392</pre>
2393</div>
2394
2395
2396<!-- _______________________________________________________________________ -->
2397
2398<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2399Instruction</a> </div>
2400
2401<div class="doc_text">
2402
2403<h5>Syntax:</h5>
2404<pre>
2405 unwind
2406</pre>
2407
2408<h5>Overview:</h5>
2409
2410<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2411at the first callee in the dynamic call stack which used an <a
2412href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2413primarily used to implement exception handling.</p>
2414
2415<h5>Semantics:</h5>
2416
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2417<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2418immediately halt. The dynamic call stack is then searched for the first <a
2419href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2420execution continues at the "exceptional" destination block specified by the
2421<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2422dynamic call chain, undefined behavior results.</p>
2423</div>
2424
2425<!-- _______________________________________________________________________ -->
2426
2427<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2428Instruction</a> </div>
2429
2430<div class="doc_text">
2431
2432<h5>Syntax:</h5>
2433<pre>
2434 unreachable
2435</pre>
2436
2437<h5>Overview:</h5>
2438
2439<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2440instruction is used to inform the optimizer that a particular portion of the
2441code is not reachable. This can be used to indicate that the code after a
2442no-return function cannot be reached, and other facts.</p>
2443
2444<h5>Semantics:</h5>
2445
2446<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2447</div>
2448
2449
2450
2451<!-- ======================================================================= -->
2452<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2453<div class="doc_text">
2454<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2455program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2456produce a single value. The operands might represent
2457multiple 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]2458The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2459<p>There are several different binary operators:</p>
2460</div>
2461<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2462<div class="doc_subsubsection">
2463 <a name="i_add">'<tt>add</tt>' Instruction</a>
2464</div>
2465
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2466<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2467
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2468<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2469
2470<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2471 &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]2472</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2473
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2474<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2475
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2476<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2477
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2478<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2479
2480<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2481 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2482 <a href="#t_vector">vector</a> values. Both arguments must have identical
2483 types.</p>
2484
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2485<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2486
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2487<p>The value produced is the integer or floating point sum of the two
2488operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2489
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2490<p>If an integer sum has unsigned overflow, the result returned is the
2491mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2492the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2493
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2494<p>Because LLVM integers use a two's complement representation, this
2495instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2496
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2497<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2498
2499<pre>
2500 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2501</pre>
2502</div>
2503<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2504<div class="doc_subsubsection">
2505 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2506</div>
2507
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2508<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2509
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2510<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2511
2512<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2513 &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]2514</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2515
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2516<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2517
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2518<p>The '<tt>sub</tt>' instruction returns the difference of its two
2519operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2520
2521<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2522'<tt>neg</tt>' instruction present in most other intermediate
2523representations.</p>
2524
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2525<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2526
2527<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2528 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2529 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2530 types.</p>
2531
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2532<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2533
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2534<p>The value produced is the integer or floating point difference of
2535the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2536
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2537<p>If an integer difference has unsigned overflow, the result returned is the
2538mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2539the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2540
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2541<p>Because LLVM integers use a two's complement representation, this
2542instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2543
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2544<h5>Example:</h5>
2545<pre>
2546 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2547 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2548</pre>
2549</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2550
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2551<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2552<div class="doc_subsubsection">
2553 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2554</div>
2555
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2556<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2557
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2558<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2559<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]2560</pre>
2561<h5>Overview:</h5>
2562<p>The '<tt>mul</tt>' instruction returns the product of its two
2563operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2564
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2565<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2566
2567<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2568href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2569or <a href="#t_vector">vector</a> values. Both arguments must have identical
2570types.</p>
2571
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2572<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2573
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2574<p>The value produced is the integer or floating point product of the
2575two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2576
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2577<p>If the result of an integer multiplication has unsigned overflow,
2578the result returned is the mathematical result modulo
25792<sup>n</sup>, where n is the bit width of the result.</p>
2580<p>Because LLVM integers use a two's complement representation, and the
2581result is the same width as the operands, this instruction returns the
2582correct result for both signed and unsigned integers. If a full product
2583(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2584should be sign-extended or zero-extended as appropriate to the
2585width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2586<h5>Example:</h5>
2587<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2588</pre>
2589</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2590
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2591<!-- _______________________________________________________________________ -->
2592<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2593</a></div>
2594<div class="doc_text">
2595<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2596<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]2597</pre>
2598<h5>Overview:</h5>
2599<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2600operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2601
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2602<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2604<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2605<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2606values. Both arguments must have identical types.</p>
2607
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2608<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2609
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2610<p>The value produced is the unsigned integer quotient of the two operands.</p>
2611<p>Note that unsigned integer division and signed integer division are distinct
2612operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2613<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2614<h5>Example:</h5>
2615<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2616</pre>
2617</div>
2618<!-- _______________________________________________________________________ -->
2619<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2620</a> </div>
2621<div class="doc_text">
2622<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2623<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2624 &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]2625</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2626
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2627<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2628
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2629<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2630operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2631
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2632<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2633
2634<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2635<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2636values. Both arguments must have identical types.</p>
2637
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2638<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2639<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]2640<p>Note that signed integer division and unsigned integer division are distinct
2641operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2642<p>Division by zero leads to undefined behavior. Overflow also leads to
2643undefined behavior; this is a rare case, but can occur, for example,
2644by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2645<h5>Example:</h5>
2646<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2647</pre>
2648</div>
2649<!-- _______________________________________________________________________ -->
2650<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2651Instruction</a> </div>
2652<div class="doc_text">
2653<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2654<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2655 &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]2656</pre>
2657<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2658
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2659<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2660operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2662<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2663
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2664<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2665<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2666of floating point values. Both arguments must have identical types.</p>
2667
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2668<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2669
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2670<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2671
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2672<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2673
2674<pre>
2675 &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]2676</pre>
2677</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2678
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2679<!-- _______________________________________________________________________ -->
2680<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2681</div>
2682<div class="doc_text">
2683<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2684<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]2685</pre>
2686<h5>Overview:</h5>
2687<p>The '<tt>urem</tt>' instruction returns the remainder from the
2688unsigned division of its two arguments.</p>
2689<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2690<p>The two arguments to the '<tt>urem</tt>' instruction must be
2691<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2692values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2693<h5>Semantics:</h5>
2694<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2695This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2696<p>Note that unsigned integer remainder and signed integer remainder are
2697distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2698<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2699<h5>Example:</h5>
2700<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2701</pre>
2702
2703</div>
2704<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2705<div class="doc_subsubsection">
2706 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2707</div>
2708
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2709<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2710
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2711<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2712
2713<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2714 &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]2715</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2716
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2717<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2718
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2719<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2720signed division of its two operands. This instruction can also take
2721<a href="#t_vector">vector</a> versions of the values in which case
2722the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2723
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2724<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2725
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2726<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2727<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2728values. Both arguments must have identical types.</p>
2729
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2730<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2731
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2732<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2733has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2734operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2735a value. For more information about the difference, see <a
2736 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2737Math Forum</a>. For a table of how this is implemented in various languages,
2738please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2739Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2740<p>Note that signed integer remainder and unsigned integer remainder are
2741distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2742<p>Taking the remainder of a division by zero leads to undefined behavior.
2743Overflow also leads to undefined behavior; this is a rare case, but can occur,
2744for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2745(The remainder doesn't actually overflow, but this rule lets srem be
2746implemented using instructions that return both the result of the division
2747and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2748<h5>Example:</h5>
2749<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2750</pre>
2751
2752</div>
2753<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2754<div class="doc_subsubsection">
2755 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2756
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2757<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2758
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2759<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2760<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]2761</pre>
2762<h5>Overview:</h5>
2763<p>The '<tt>frem</tt>' instruction returns the remainder from the
2764division of its two operands.</p>
2765<h5>Arguments:</h5>
2766<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2767<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2768of floating point values. Both arguments must have identical types.</p>
2769
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2770<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2771
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2772<p>This instruction returns the <i>remainder</i> of a division.
2773The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2774
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2775<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2776
2777<pre>
2778 &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]2779</pre>
2780</div>
2781
2782<!-- ======================================================================= -->
2783<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2784Operations</a> </div>
2785<div class="doc_text">
2786<p>Bitwise binary operators are used to do various forms of
2787bit-twiddling in a program. They are generally very efficient
2788instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2789instructions. They require two operands of the same type, execute an operation on them,
2790and 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]2791</div>
2792
2793<!-- _______________________________________________________________________ -->
2794<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2795Instruction</a> </div>
2796<div class="doc_text">
2797<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2798<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]2799</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2800
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2801<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2803<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2804the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2805
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2806<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2807
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2808<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2809 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2810type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2811
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2812<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2813
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2814<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2815where 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]2816equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2817If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2818corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2819
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2820<h5>Example:</h5><pre>
2821 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2822 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2823 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2824 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2825 &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]2826</pre>
2827</div>
2828<!-- _______________________________________________________________________ -->
2829<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2830Instruction</a> </div>
2831<div class="doc_text">
2832<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2833<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]2834</pre>
2835
2836<h5>Overview:</h5>
2837<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2838operand shifted to the right a specified number of bits with zero fill.</p>
2839
2840<h5>Arguments:</h5>
2841<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2842<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]2843type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2844
2845<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2846
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2847<p>This instruction always performs a logical shift right operation. The most
2848significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2849shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2850the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2851vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2852amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2853
2854<h5>Example:</h5>
2855<pre>
2856 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2857 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2858 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2859 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2860 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2861 &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]2862</pre>
2863</div>
2864
2865<!-- _______________________________________________________________________ -->
2866<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2867Instruction</a> </div>
2868<div class="doc_text">
2869
2870<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2871<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]2872</pre>
2873
2874<h5>Overview:</h5>
2875<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2876operand shifted to the right a specified number of bits with sign extension.</p>
2877
2878<h5>Arguments:</h5>
2879<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2880<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]2881type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2882
2883<h5>Semantics:</h5>
2884<p>This instruction always performs an arithmetic shift right operation,
2885The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2886of <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]2887larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
2888arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2889corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2890
2891<h5>Example:</h5>
2892<pre>
2893 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2894 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2895 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2896 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2897 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2898 &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]2899</pre>
2900</div>
2901
2902<!-- _______________________________________________________________________ -->
2903<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2904Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2905
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2906<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2907
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2908<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2909
2910<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2911 &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]2912</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2913
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2914<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2915
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2916<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2917its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2918
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2919<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2920
2921<p>The two arguments to the '<tt>and</tt>' instruction must be
2922<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2923values. Both arguments must have identical types.</p>
2924
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2925<h5>Semantics:</h5>
2926<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2927<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2928<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2929<table border="1" cellspacing="0" cellpadding="4">
2930 <tbody>
2931 <tr>
2932 <td>In0</td>
2933 <td>In1</td>
2934 <td>Out</td>
2935 </tr>
2936 <tr>
2937 <td>0</td>
2938 <td>0</td>
2939 <td>0</td>
2940 </tr>
2941 <tr>
2942 <td>0</td>
2943 <td>1</td>
2944 <td>0</td>
2945 </tr>
2946 <tr>
2947 <td>1</td>
2948 <td>0</td>
2949 <td>0</td>
2950 </tr>
2951 <tr>
2952 <td>1</td>
2953 <td>1</td>
2954 <td>1</td>
2955 </tr>
2956 </tbody>
2957</table>
2958</div>
2959<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2960<pre>
2961 &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]2962 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2963 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2964</pre>
2965</div>
2966<!-- _______________________________________________________________________ -->
2967<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2968<div class="doc_text">
2969<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2970<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]2971</pre>
2972<h5>Overview:</h5>
2973<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2974or of its two operands.</p>
2975<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2976
2977<p>The two arguments to the '<tt>or</tt>' instruction must be
2978<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2979values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2980<h5>Semantics:</h5>
2981<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2982<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2983<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2984<table border="1" cellspacing="0" cellpadding="4">
2985 <tbody>
2986 <tr>
2987 <td>In0</td>
2988 <td>In1</td>
2989 <td>Out</td>
2990 </tr>
2991 <tr>
2992 <td>0</td>
2993 <td>0</td>
2994 <td>0</td>
2995 </tr>
2996 <tr>
2997 <td>0</td>
2998 <td>1</td>
2999 <td>1</td>
3000 </tr>
3001 <tr>
3002 <td>1</td>
3003 <td>0</td>
3004 <td>1</td>
3005 </tr>
3006 <tr>
3007 <td>1</td>
3008 <td>1</td>
3009 <td>1</td>
3010 </tr>
3011 </tbody>
3012</table>
3013</div>
3014<h5>Example:</h5>
3015<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
3016 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3017 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3018</pre>
3019</div>
3020<!-- _______________________________________________________________________ -->
3021<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3022Instruction</a> </div>
3023<div class="doc_text">
3024<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3025<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]3026</pre>
3027<h5>Overview:</h5>
3028<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
3029or of its two operands. The <tt>xor</tt> is used to implement the
3030"one's complement" operation, which is the "~" operator in C.</p>
3031<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3032<p>The two arguments to the '<tt>xor</tt>' instruction must be
3033<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3034values. Both arguments must have identical types.</p>
3035
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3036<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3037
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3038<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
3039<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3040<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3041<table border="1" cellspacing="0" cellpadding="4">
3042 <tbody>
3043 <tr>
3044 <td>In0</td>
3045 <td>In1</td>
3046 <td>Out</td>
3047 </tr>
3048 <tr>
3049 <td>0</td>
3050 <td>0</td>
3051 <td>0</td>
3052 </tr>
3053 <tr>
3054 <td>0</td>
3055 <td>1</td>
3056 <td>1</td>
3057 </tr>
3058 <tr>
3059 <td>1</td>
3060 <td>0</td>
3061 <td>1</td>
3062 </tr>
3063 <tr>
3064 <td>1</td>
3065 <td>1</td>
3066 <td>0</td>
3067 </tr>
3068 </tbody>
3069</table>
3070</div>
3071<p> </p>
3072<h5>Example:</h5>
3073<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
3074 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3075 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3076 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3077</pre>
3078</div>
3079
3080<!-- ======================================================================= -->
3081<div class="doc_subsection">
3082 <a name="vectorops">Vector Operations</a>
3083</div>
3084
3085<div class="doc_text">
3086
3087<p>LLVM supports several instructions to represent vector operations in a
3088target-independent manner. These instructions cover the element-access and
3089vector-specific operations needed to process vectors effectively. While LLVM
3090does directly support these vector operations, many sophisticated algorithms
3091will want to use target-specific intrinsics to take full advantage of a specific
3092target.</p>
3093
3094</div>
3095
3096<!-- _______________________________________________________________________ -->
3097<div class="doc_subsubsection">
3098 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3099</div>
3100
3101<div class="doc_text">
3102
3103<h5>Syntax:</h5>
3104
3105<pre>
3106 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3107</pre>
3108
3109<h5>Overview:</h5>
3110
3111<p>
3112The '<tt>extractelement</tt>' instruction extracts a single scalar
3113element from a vector at a specified index.
3114</p>
3115
3116
3117<h5>Arguments:</h5>
3118
3119<p>
3120The first operand of an '<tt>extractelement</tt>' instruction is a
3121value of <a href="#t_vector">vector</a> type. The second operand is
3122an index indicating the position from which to extract the element.
3123The index may be a variable.</p>
3124
3125<h5>Semantics:</h5>
3126
3127<p>
3128The result is a scalar of the same type as the element type of
3129<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3130<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3131results are undefined.
3132</p>
3133
3134<h5>Example:</h5>
3135
3136<pre>
3137 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3138</pre>
3139</div>
3140
3141
3142<!-- _______________________________________________________________________ -->
3143<div class="doc_subsubsection">
3144 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3145</div>
3146
3147<div class="doc_text">
3148
3149<h5>Syntax:</h5>
3150
3151<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3152 &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]3153</pre>
3154
3155<h5>Overview:</h5>
3156
3157<p>
3158The '<tt>insertelement</tt>' instruction inserts a scalar
3159element into a vector at a specified index.
3160</p>
3161
3162
3163<h5>Arguments:</h5>
3164
3165<p>
3166The first operand of an '<tt>insertelement</tt>' instruction is a
3167value of <a href="#t_vector">vector</a> type. The second operand is a
3168scalar value whose type must equal the element type of the first
3169operand. The third operand is an index indicating the position at
3170which to insert the value. The index may be a variable.</p>
3171
3172<h5>Semantics:</h5>
3173
3174<p>
3175The result is a vector of the same type as <tt>val</tt>. Its
3176element values are those of <tt>val</tt> except at position
3177<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
3178exceeds the length of <tt>val</tt>, the results are undefined.
3179</p>
3180
3181<h5>Example:</h5>
3182
3183<pre>
3184 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3185</pre>
3186</div>
3187
3188<!-- _______________________________________________________________________ -->
3189<div class="doc_subsubsection">
3190 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3191</div>
3192
3193<div class="doc_text">
3194
3195<h5>Syntax:</h5>
3196
3197<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3198 &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]3199</pre>
3200
3201<h5>Overview:</h5>
3202
3203<p>
3204The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3205from two input vectors, returning a vector with the same element type as
3206the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3207</p>
3208
3209<h5>Arguments:</h5>
3210
3211<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3212The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3213with types that match each other. The third argument is a shuffle mask whose
3214element type is always 'i32'. The result of the instruction is a vector whose
3215length is the same as the shuffle mask and whose element type is the same as
3216the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3217</p>
3218
3219<p>
3220The shuffle mask operand is required to be a constant vector with either
3221constant integer or undef values.
3222</p>
3223
3224<h5>Semantics:</h5>
3225
3226<p>
3227The elements of the two input vectors are numbered from left to right across
3228both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3229the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3230gets. The element selector may be undef (meaning "don't care") and the second
3231operand may be undef if performing a shuffle from only one vector.
3232</p>
3233
3234<h5>Example:</h5>
3235
3236<pre>
3237 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3238 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3239 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3240 &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]3241 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3242 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3243 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3244 &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]3245</pre>
3246</div>
3247
3248
3249<!-- ======================================================================= -->
3250<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3251 <a name="aggregateops">Aggregate Operations</a>
3252</div>
3253
3254<div class="doc_text">
3255
3256<p>LLVM supports several instructions for working with aggregate values.
3257</p>
3258
3259</div>
3260
3261<!-- _______________________________________________________________________ -->
3262<div class="doc_subsubsection">
3263 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3264</div>
3265
3266<div class="doc_text">
3267
3268<h5>Syntax:</h5>
3269
3270<pre>
3271 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3272</pre>
3273
3274<h5>Overview:</h5>
3275
3276<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3277The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3278or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3279</p>
3280
3281
3282<h5>Arguments:</h5>
3283
3284<p>
3285The first operand of an '<tt>extractvalue</tt>' instruction is a
3286value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3287type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3288in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3289'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3290</p>
3291
3292<h5>Semantics:</h5>
3293
3294<p>
3295The result is the value at the position in the aggregate specified by
3296the index operands.
3297</p>
3298
3299<h5>Example:</h5>
3300
3301<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3302 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3303</pre>
3304</div>
3305
3306
3307<!-- _______________________________________________________________________ -->
3308<div class="doc_subsubsection">
3309 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3310</div>
3311
3312<div class="doc_text">
3313
3314<h5>Syntax:</h5>
3315
3316<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3317 &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]3318</pre>
3319
3320<h5>Overview:</h5>
3321
3322<p>
3323The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3324into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3325</p>
3326
3327
3328<h5>Arguments:</h5>
3329
3330<p>
3331The first operand of an '<tt>insertvalue</tt>' instruction is a
3332value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3333The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3334The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3335indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3336indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3337'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3338The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3339by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3340</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3341
3342<h5>Semantics:</h5>
3343
3344<p>
3345The result is an aggregate of the same type as <tt>val</tt>. Its
3346value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3347specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3348</p>
3349
3350<h5>Example:</h5>
3351
3352<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3353 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3354</pre>
3355</div>
3356
3357
3358<!-- ======================================================================= -->
3359<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3360 <a name="memoryops">Memory Access and Addressing Operations</a>
3361</div>
3362
3363<div class="doc_text">
3364
3365<p>A key design point of an SSA-based representation is how it
3366represents memory. In LLVM, no memory locations are in SSA form, which
3367makes things very simple. This section describes how to read, write,
3368allocate, and free memory in LLVM.</p>
3369
3370</div>
3371
3372<!-- _______________________________________________________________________ -->
3373<div class="doc_subsubsection">
3374 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3375</div>
3376
3377<div class="doc_text">
3378
3379<h5>Syntax:</h5>
3380
3381<pre>
3382 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3383</pre>
3384
3385<h5>Overview:</h5>
3386
3387<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3388heap and returns a pointer to it. The object is always allocated in the generic
3389address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3390
3391<h5>Arguments:</h5>
3392
3393<p>The '<tt>malloc</tt>' instruction allocates
3394<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3395bytes of memory from the operating system and returns a pointer of the
3396appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3397number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3398If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3399be aligned to at least that boundary. If not specified, or if zero, the target can
3400choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3401
3402<p>'<tt>type</tt>' must be a sized type.</p>
3403
3404<h5>Semantics:</h5>
3405
3406<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3407a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3408result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3409
3410<h5>Example:</h5>
3411
3412<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3413 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3414
3415 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3416 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3417 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3418 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3419 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3420</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3421
3422<p>Note that the code generator does not yet respect the
3423 alignment value.</p>
3424
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3425</div>
3426
3427<!-- _______________________________________________________________________ -->
3428<div class="doc_subsubsection">
3429 <a name="i_free">'<tt>free</tt>' Instruction</a>
3430</div>
3431
3432<div class="doc_text">
3433
3434<h5>Syntax:</h5>
3435
3436<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3437 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3438</pre>
3439
3440<h5>Overview:</h5>
3441
3442<p>The '<tt>free</tt>' instruction returns memory back to the unused
3443memory heap to be reallocated in the future.</p>
3444
3445<h5>Arguments:</h5>
3446
3447<p>'<tt>value</tt>' shall be a pointer value that points to a value
3448that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3449instruction.</p>
3450
3451<h5>Semantics:</h5>
3452
3453<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3454after this instruction executes. If the pointer is null, the operation
3455is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3456
3457<h5>Example:</h5>
3458
3459<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3460 %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]3461 free [4 x i8]* %array
3462</pre>
3463</div>
3464
3465<!-- _______________________________________________________________________ -->
3466<div class="doc_subsubsection">
3467 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3468</div>
3469
3470<div class="doc_text">
3471
3472<h5>Syntax:</h5>
3473
3474<pre>
3475 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3476</pre>
3477
3478<h5>Overview:</h5>
3479
3480<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3481currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3482returns to its caller. The object is always allocated in the generic address
3483space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3484
3485<h5>Arguments:</h5>
3486
3487<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3488bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3489appropriate type to the program. If "NumElements" is specified, it is the
3490number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3491If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3492to be aligned to at least that boundary. If not specified, or if zero, the target
3493can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3494
3495<p>'<tt>type</tt>' may be any sized type.</p>
3496
3497<h5>Semantics:</h5>
3498
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3499<p>Memory is allocated; a pointer is returned. The operation is undefined if
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3500there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3501memory is automatically released when the function returns. The '<tt>alloca</tt>'
3502instruction is commonly used to represent automatic variables that must
3503have an address available. When the function returns (either with the <tt><a
3504 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]3505instructions), the memory is reclaimed. Allocating zero bytes
3506is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3507
3508<h5>Example:</h5>
3509
3510<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3511 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3512 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3513 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3514 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3515</pre>
3516</div>
3517
3518<!-- _______________________________________________________________________ -->
3519<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3520Instruction</a> </div>
3521<div class="doc_text">
3522<h5>Syntax:</h5>
3523<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>
3524<h5>Overview:</h5>
3525<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3526<h5>Arguments:</h5>
3527<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3528address from which to load. The pointer must point to a <a
3529 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3530marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3531the number or order of execution of this <tt>load</tt> with other
3532volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3533instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3534<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3535The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3536(that is, the alignment of the memory address). A value of 0 or an
3537omitted "align" argument means that the operation has the preferential
3538alignment for the target. It is the responsibility of the code emitter
3539to ensure that the alignment information is correct. Overestimating
3540the alignment results in an undefined behavior. Underestimating the
3541alignment may produce less efficient code. An alignment of 1 is always
3542safe.
3543</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3544<h5>Semantics:</h5>
Duncan Sandsfe87fff2009-03-22 11:33:16 +0000[diff] [blame]3545<p>The location of memory pointed to is loaded. If the value being loaded
3546is of scalar type then the number of bytes read does not exceed the minimum
3547number of bytes needed to hold all bits of the type. For example, loading an
3548<tt>i24</tt> reads at most three bytes. When loading a value of a type like
3549<tt>i20</tt> with a size that is not an integral number of bytes, the result
3550is undefined if the value was not originally written using a store of the
3551same type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3552<h5>Examples:</h5>
3553<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3554 <a
3555 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3556 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3557</pre>
3558</div>
3559<!-- _______________________________________________________________________ -->
3560<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3561Instruction</a> </div>
3562<div class="doc_text">
3563<h5>Syntax:</h5>
3564<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3565 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3566</pre>
3567<h5>Overview:</h5>
3568<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3569<h5>Arguments:</h5>
3570<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3571to 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]3572operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3573of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3574operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3575optimizer is not allowed to modify the number or order of execution of
3576this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3577 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3578<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3579The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3580(that is, the alignment of the memory address). A value of 0 or an
3581omitted "align" argument means that the operation has the preferential
3582alignment for the target. It is the responsibility of the code emitter
3583to ensure that the alignment information is correct. Overestimating
3584the alignment results in an undefined behavior. Underestimating the
3585alignment may produce less efficient code. An alignment of 1 is always
3586safe.
3587</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3588<h5>Semantics:</h5>
3589<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
Duncan Sandsfe87fff2009-03-22 11:33:16 +0000[diff] [blame]3590at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.
3591If '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes
3592written does not exceed the minimum number of bytes needed to hold all
3593bits of the type. For example, storing an <tt>i24</tt> writes at most
3594three bytes. When writing a value of a type like <tt>i20</tt> with a
3595size that is not an integral number of bytes, it is unspecified what
3596happens to the extra bits that do not belong to the type, but they will
3597typically be overwritten.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3598<h5>Example:</h5>
3599<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3600 store i32 3, i32* %ptr <i>; yields {void}</i>
3601 %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]3602</pre>
3603</div>
3604
3605<!-- _______________________________________________________________________ -->
3606<div class="doc_subsubsection">
3607 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3608</div>
3609
3610<div class="doc_text">
3611<h5>Syntax:</h5>
3612<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3613 &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]3614</pre>
3615
3616<h5>Overview:</h5>
3617
3618<p>
3619The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3620subelement of an aggregate data structure. It performs address calculation only
3621and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3622
3623<h5>Arguments:</h5>
3624
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3625<p>The first argument is always a pointer, and forms the basis of the
3626calculation. The remaining arguments are indices, that indicate which of the
3627elements of the aggregate object are indexed. The interpretation of each index
3628is dependent on the type being indexed into. The first index always indexes the
3629pointer value given as the first argument, the second index indexes a value of
3630the type pointed to (not necessarily the value directly pointed to, since the
3631first index can be non-zero), etc. The first type indexed into must be a pointer
3632value, subsequent types can be arrays, vectors and structs. Note that subsequent
3633types being indexed into can never be pointers, since that would require loading
3634the pointer before continuing calculation.</p>
3635
3636<p>The type of each index argument depends on the type it is indexing into.
3637When indexing into a (packed) structure, only <tt>i32</tt> integer
3638<b>constants</b> are allowed. When indexing into an array, pointer or vector,
Sanjiv Guptaa2e72d92009-04-27 03:21:00 +0000[diff] [blame]3639integers of any width are allowed (also non-constants).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3640
3641<p>For example, let's consider a C code fragment and how it gets
3642compiled to LLVM:</p>
3643
3644<div class="doc_code">
3645<pre>
3646struct RT {
3647 char A;
3648 int B[10][20];
3649 char C;
3650};
3651struct ST {
3652 int X;
3653 double Y;
3654 struct RT Z;
3655};
3656
3657int *foo(struct ST *s) {
3658 return &amp;s[1].Z.B[5][13];
3659}
3660</pre>
3661</div>
3662
3663<p>The LLVM code generated by the GCC frontend is:</p>
3664
3665<div class="doc_code">
3666<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]3667%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3668%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3669
3670define i32* %foo(%ST* %s) {
3671entry:
3672 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3673 ret i32* %reg
3674}
3675</pre>
3676</div>
3677
3678<h5>Semantics:</h5>
3679
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3680<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3681type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3682}</tt>' type, a structure. The second index indexes into the third element of
3683the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3684i8 }</tt>' type, another structure. The third index indexes into the second
3685element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3686array. The two dimensions of the array are subscripted into, yielding an
3687'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3688to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3689
3690<p>Note that it is perfectly legal to index partially through a
3691structure, returning a pointer to an inner element. Because of this,
3692the LLVM code for the given testcase is equivalent to:</p>
3693
3694<pre>
3695 define i32* %foo(%ST* %s) {
3696 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3697 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3698 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3699 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3700 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3701 ret i32* %t5
3702 }
3703</pre>
3704
Chris Lattner50609942009-03-09 20:55:18 +0000[diff] [blame]3705<p>Note that it is undefined to access an array out of bounds: array
3706and pointer indexes must always be within the defined bounds of the
3707array type when accessed with an instruction that dereferences the
3708pointer (e.g. a load or store instruction). The one exception for
3709this rule is zero length arrays. These arrays are defined to be
3710accessible as variable length arrays, which requires access beyond the
3711zero'th element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3712
3713<p>The getelementptr instruction is often confusing. For some more insight
3714into how it works, see <a href="GetElementPtr.html">the getelementptr
3715FAQ</a>.</p>
3716
3717<h5>Example:</h5>
3718
3719<pre>
3720 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3721 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3722 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3723 %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]3724 <i>; yields i8*:eptr</i>
3725 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]3726 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]3727 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3728</pre>
3729</div>
3730
3731<!-- ======================================================================= -->
3732<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3733</div>
3734<div class="doc_text">
3735<p>The instructions in this category are the conversion instructions (casting)
3736which all take a single operand and a type. They perform various bit conversions
3737on the operand.</p>
3738</div>
3739
3740<!-- _______________________________________________________________________ -->
3741<div class="doc_subsubsection">
3742 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3743</div>
3744<div class="doc_text">
3745
3746<h5>Syntax:</h5>
3747<pre>
3748 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3749</pre>
3750
3751<h5>Overview:</h5>
3752<p>
3753The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3754</p>
3755
3756<h5>Arguments:</h5>
3757<p>
3758The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3759be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3760and type of the result, which must be an <a href="#t_integer">integer</a>
3761type. The bit size of <tt>value</tt> must be larger than the bit size of
3762<tt>ty2</tt>. Equal sized types are not allowed.</p>
3763
3764<h5>Semantics:</h5>
3765<p>
3766The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3767and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3768larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3769It will always truncate bits.</p>
3770
3771<h5>Example:</h5>
3772<pre>
3773 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3774 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3775 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3776</pre>
3777</div>
3778
3779<!-- _______________________________________________________________________ -->
3780<div class="doc_subsubsection">
3781 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3782</div>
3783<div class="doc_text">
3784
3785<h5>Syntax:</h5>
3786<pre>
3787 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3788</pre>
3789
3790<h5>Overview:</h5>
3791<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3792<tt>ty2</tt>.</p>
3793
3794
3795<h5>Arguments:</h5>
3796<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3797<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3798also be of <a href="#t_integer">integer</a> type. The bit size of the
3799<tt>value</tt> must be smaller than the bit size of the destination type,
3800<tt>ty2</tt>.</p>
3801
3802<h5>Semantics:</h5>
3803<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3804bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3805
3806<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3807
3808<h5>Example:</h5>
3809<pre>
3810 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3811 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3812</pre>
3813</div>
3814
3815<!-- _______________________________________________________________________ -->
3816<div class="doc_subsubsection">
3817 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3818</div>
3819<div class="doc_text">
3820
3821<h5>Syntax:</h5>
3822<pre>
3823 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3824</pre>
3825
3826<h5>Overview:</h5>
3827<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3828
3829<h5>Arguments:</h5>
3830<p>
3831The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3832<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3833also be of <a href="#t_integer">integer</a> type. The bit size of the
3834<tt>value</tt> must be smaller than the bit size of the destination type,
3835<tt>ty2</tt>.</p>
3836
3837<h5>Semantics:</h5>
3838<p>
3839The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3840bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3841the type <tt>ty2</tt>.</p>
3842
3843<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3844
3845<h5>Example:</h5>
3846<pre>
3847 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3848 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3849</pre>
3850</div>
3851
3852<!-- _______________________________________________________________________ -->
3853<div class="doc_subsubsection">
3854 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3855</div>
3856
3857<div class="doc_text">
3858
3859<h5>Syntax:</h5>
3860
3861<pre>
3862 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3863</pre>
3864
3865<h5>Overview:</h5>
3866<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3867<tt>ty2</tt>.</p>
3868
3869
3870<h5>Arguments:</h5>
3871<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3872 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3873cast it to. The size of <tt>value</tt> must be larger than the size of
3874<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3875<i>no-op cast</i>.</p>
3876
3877<h5>Semantics:</h5>
3878<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3879<a href="#t_floating">floating point</a> type to a smaller
3880<a href="#t_floating">floating point</a> type. If the value cannot fit within
3881the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3882
3883<h5>Example:</h5>
3884<pre>
3885 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3886 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3887</pre>
3888</div>
3889
3890<!-- _______________________________________________________________________ -->
3891<div class="doc_subsubsection">
3892 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3893</div>
3894<div class="doc_text">
3895
3896<h5>Syntax:</h5>
3897<pre>
3898 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3899</pre>
3900
3901<h5>Overview:</h5>
3902<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3903floating point value.</p>
3904
3905<h5>Arguments:</h5>
3906<p>The '<tt>fpext</tt>' instruction takes a
3907<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3908and a <a href="#t_floating">floating point</a> type to cast it to. The source
3909type must be smaller than the destination type.</p>
3910
3911<h5>Semantics:</h5>
3912<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3913<a href="#t_floating">floating point</a> type to a larger
3914<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3915used to make a <i>no-op cast</i> because it always changes bits. Use
3916<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3917
3918<h5>Example:</h5>
3919<pre>
3920 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3921 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3922</pre>
3923</div>
3924
3925<!-- _______________________________________________________________________ -->
3926<div class="doc_subsubsection">
3927 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3928</div>
3929<div class="doc_text">
3930
3931<h5>Syntax:</h5>
3932<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3933 &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]3934</pre>
3935
3936<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3937<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3938unsigned integer equivalent of type <tt>ty2</tt>.
3939</p>
3940
3941<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3942<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]3943scalar or vector <a href="#t_floating">floating point</a> value, and a type
3944to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3945type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3946vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3947
3948<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3949<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3950<a href="#t_floating">floating point</a> operand into the nearest (rounding
3951towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3952the results are undefined.</p>
3953
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3954<h5>Example:</h5>
3955<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3956 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3957 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3958 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3959</pre>
3960</div>
3961
3962<!-- _______________________________________________________________________ -->
3963<div class="doc_subsubsection">
3964 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3965</div>
3966<div class="doc_text">
3967
3968<h5>Syntax:</h5>
3969<pre>
3970 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3971</pre>
3972
3973<h5>Overview:</h5>
3974<p>The '<tt>fptosi</tt>' instruction converts
3975<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3976</p>
3977
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3978<h5>Arguments:</h5>
3979<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]3980scalar or vector <a href="#t_floating">floating point</a> value, and a type
3981to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3982type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3983vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3984
3985<h5>Semantics:</h5>
3986<p>The '<tt>fptosi</tt>' instruction converts its
3987<a href="#t_floating">floating point</a> operand into the nearest (rounding
3988towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3989the results are undefined.</p>
3990
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3991<h5>Example:</h5>
3992<pre>
3993 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3994 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3995 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3996</pre>
3997</div>
3998
3999<!-- _______________________________________________________________________ -->
4000<div class="doc_subsubsection">
4001 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4002</div>
4003<div class="doc_text">
4004
4005<h5>Syntax:</h5>
4006<pre>
4007 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4008</pre>
4009
4010<h5>Overview:</h5>
4011<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
4012integer and converts that value to the <tt>ty2</tt> type.</p>
4013
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4014<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4015<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
4016scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4017to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4018type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4019floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4020
4021<h5>Semantics:</h5>
4022<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
4023integer quantity and converts it to the corresponding floating point value. If
4024the value cannot fit in the floating point value, the results are undefined.</p>
4025
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4026<h5>Example:</h5>
4027<pre>
4028 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4029 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4030</pre>
4031</div>
4032
4033<!-- _______________________________________________________________________ -->
4034<div class="doc_subsubsection">
4035 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4036</div>
4037<div class="doc_text">
4038
4039<h5>Syntax:</h5>
4040<pre>
4041 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4042</pre>
4043
4044<h5>Overview:</h5>
4045<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
4046integer and converts that value to the <tt>ty2</tt> type.</p>
4047
4048<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4049<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
4050scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4051to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4052type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4053floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4054
4055<h5>Semantics:</h5>
4056<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
4057integer quantity and converts it to the corresponding floating point value. If
4058the value cannot fit in the floating point value, the results are undefined.</p>
4059
4060<h5>Example:</h5>
4061<pre>
4062 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4063 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4064</pre>
4065</div>
4066
4067<!-- _______________________________________________________________________ -->
4068<div class="doc_subsubsection">
4069 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4070</div>
4071<div class="doc_text">
4072
4073<h5>Syntax:</h5>
4074<pre>
4075 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4076</pre>
4077
4078<h5>Overview:</h5>
4079<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4080the integer type <tt>ty2</tt>.</p>
4081
4082<h5>Arguments:</h5>
4083<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4084must 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]4085<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]4086
4087<h5>Semantics:</h5>
4088<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
4089<tt>ty2</tt> by interpreting the pointer value as an integer and either
4090truncating or zero extending that value to the size of the integer type. If
4091<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4092<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4093are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4094change.</p>
4095
4096<h5>Example:</h5>
4097<pre>
4098 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4099 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4100</pre>
4101</div>
4102
4103<!-- _______________________________________________________________________ -->
4104<div class="doc_subsubsection">
4105 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4106</div>
4107<div class="doc_text">
4108
4109<h5>Syntax:</h5>
4110<pre>
4111 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4112</pre>
4113
4114<h5>Overview:</h5>
4115<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
4116a pointer type, <tt>ty2</tt>.</p>
4117
4118<h5>Arguments:</h5>
4119<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
4120value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4121<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4122
4123<h5>Semantics:</h5>
4124<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
4125<tt>ty2</tt> by applying either a zero extension or a truncation depending on
4126the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4127size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
4128the size of a pointer then a zero extension is done. If they are the same size,
4129nothing is done (<i>no-op cast</i>).</p>
4130
4131<h5>Example:</h5>
4132<pre>
4133 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4134 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4135 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4136</pre>
4137</div>
4138
4139<!-- _______________________________________________________________________ -->
4140<div class="doc_subsubsection">
4141 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4142</div>
4143<div class="doc_text">
4144
4145<h5>Syntax:</h5>
4146<pre>
4147 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4148</pre>
4149
4150<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4151
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4152<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4153<tt>ty2</tt> without changing any bits.</p>
4154
4155<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4156
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4157<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]4158a non-aggregate first class value, and a type to cast it to, which must also be
4159a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
4160<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4161and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4162type is a pointer, the destination type must also be a pointer. This
4163instruction supports bitwise conversion of vectors to integers and to vectors
4164of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4165
4166<h5>Semantics:</h5>
4167<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4168<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4169this conversion. The conversion is done as if the <tt>value</tt> had been
4170stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
4171converted to other pointer types with this instruction. To convert pointers to
4172other types, use the <a href="#i_inttoptr">inttoptr</a> or
4173<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
4174
4175<h5>Example:</h5>
4176<pre>
4177 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4178 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4179 %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]4180</pre>
4181</div>
4182
4183<!-- ======================================================================= -->
4184<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
4185<div class="doc_text">
4186<p>The instructions in this category are the "miscellaneous"
4187instructions, which defy better classification.</p>
4188</div>
4189
4190<!-- _______________________________________________________________________ -->
4191<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4192</div>
4193<div class="doc_text">
4194<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4195<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]4196</pre>
4197<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4198<p>The '<tt>icmp</tt>' instruction returns a boolean value or
4199a vector of boolean values based on comparison
4200of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4201<h5>Arguments:</h5>
4202<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
4203the condition code indicating the kind of comparison to perform. It is not
4204a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4205</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4206<ol>
4207 <li><tt>eq</tt>: equal</li>
4208 <li><tt>ne</tt>: not equal </li>
4209 <li><tt>ugt</tt>: unsigned greater than</li>
4210 <li><tt>uge</tt>: unsigned greater or equal</li>
4211 <li><tt>ult</tt>: unsigned less than</li>
4212 <li><tt>ule</tt>: unsigned less or equal</li>
4213 <li><tt>sgt</tt>: signed greater than</li>
4214 <li><tt>sge</tt>: signed greater or equal</li>
4215 <li><tt>slt</tt>: signed less than</li>
4216 <li><tt>sle</tt>: signed less or equal</li>
4217</ol>
4218<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4219<a href="#t_pointer">pointer</a>
4220or integer <a href="#t_vector">vector</a> typed.
4221They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4222<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4223<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]4224the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4225yields 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]4226</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4227<ol>
4228 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
4229 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
4230 </li>
4231 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4232 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4233 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4234 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4235 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4236 <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]4237 <li><tt>ult</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 less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4239 <li><tt>ule</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 less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4241 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4242 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4243 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4244 <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]4245 <li><tt>slt</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 less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4247 <li><tt>sle</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 less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4249</ol>
4250<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4251values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4252<p>If the operands are integer vectors, then they are compared
4253element by element. The result is an <tt>i1</tt> vector with
4254the same number of elements as the values being compared.
4255Otherwise, the result is an <tt>i1</tt>.
4256</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4257
4258<h5>Example:</h5>
4259<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4260 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4261 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4262 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4263 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4264 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4265</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4266
4267<p>Note that the code generator does not yet support vector types with
4268 the <tt>icmp</tt> instruction.</p>
4269
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4270</div>
4271
4272<!-- _______________________________________________________________________ -->
4273<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4274</div>
4275<div class="doc_text">
4276<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4277<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]4278</pre>
4279<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4280<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4281or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4282of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4283<p>
4284If the operands are floating point scalars, then the result
4285type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4286</p>
4287<p>If the operands are floating point vectors, then the result type
4288is a vector of boolean with the same number of elements as the
4289operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4290<h5>Arguments:</h5>
4291<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4292the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4293a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4294<ol>
4295 <li><tt>false</tt>: no comparison, always returns false</li>
4296 <li><tt>oeq</tt>: ordered and equal</li>
4297 <li><tt>ogt</tt>: ordered and greater than </li>
4298 <li><tt>oge</tt>: ordered and greater than or equal</li>
4299 <li><tt>olt</tt>: ordered and less than </li>
4300 <li><tt>ole</tt>: ordered and less than or equal</li>
4301 <li><tt>one</tt>: ordered and not equal</li>
4302 <li><tt>ord</tt>: ordered (no nans)</li>
4303 <li><tt>ueq</tt>: unordered or equal</li>
4304 <li><tt>ugt</tt>: unordered or greater than </li>
4305 <li><tt>uge</tt>: unordered or greater than or equal</li>
4306 <li><tt>ult</tt>: unordered or less than </li>
4307 <li><tt>ule</tt>: unordered or less than or equal</li>
4308 <li><tt>une</tt>: unordered or not equal</li>
4309 <li><tt>uno</tt>: unordered (either nans)</li>
4310 <li><tt>true</tt>: no comparison, always returns true</li>
4311</ol>
4312<p><i>Ordered</i> means that neither operand is a QNAN while
4313<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4314<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4315either a <a href="#t_floating">floating point</a> type
4316or a <a href="#t_vector">vector</a> of floating point type.
4317They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4318<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4319<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4320according to the condition code given as <tt>cond</tt>.
4321If the operands are vectors, then the vectors are compared
4322element by element.
4323Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4324always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4325<ol>
4326 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4327 <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]4328 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4329 <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]4330 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4331 <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]4332 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4333 <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]4334 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4335 <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]4336 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4337 <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]4338 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4339 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4340 <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]4341 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4342 <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]4343 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4344 <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]4345 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4346 <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]4347 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4348 <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]4349 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4350 <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]4351 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4352 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4353 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4354</ol>
4355
4356<h5>Example:</h5>
4357<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]4358 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4359 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4360 &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]4361</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4362
4363<p>Note that the code generator does not yet support vector types with
4364 the <tt>fcmp</tt> instruction.</p>
4365
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4366</div>
4367
4368<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4369<div class="doc_subsubsection">
4370 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4371</div>
4372<div class="doc_text">
4373<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4374<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]4375</pre>
4376<h5>Overview:</h5>
4377<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4378element-wise comparison of its two integer vector operands.</p>
4379<h5>Arguments:</h5>
4380<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4381the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4382a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4383<ol>
4384 <li><tt>eq</tt>: equal</li>
4385 <li><tt>ne</tt>: not equal </li>
4386 <li><tt>ugt</tt>: unsigned greater than</li>
4387 <li><tt>uge</tt>: unsigned greater or equal</li>
4388 <li><tt>ult</tt>: unsigned less than</li>
4389 <li><tt>ule</tt>: unsigned less or equal</li>
4390 <li><tt>sgt</tt>: signed greater than</li>
4391 <li><tt>sge</tt>: signed greater or equal</li>
4392 <li><tt>slt</tt>: signed less than</li>
4393 <li><tt>sle</tt>: signed less or equal</li>
4394</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4395<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4396<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4397<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4398<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4399according to the condition code given as <tt>cond</tt>. The comparison yields a
4400<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4401identical type as the values being compared. The most significant bit in each
4402element is 1 if the element-wise comparison evaluates to true, and is 0
4403otherwise. All other bits of the result are undefined. The condition codes
4404are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4405instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4406
4407<h5>Example:</h5>
4408<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4409 &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>
4410 &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]4411</pre>
4412</div>
4413
4414<!-- _______________________________________________________________________ -->
4415<div class="doc_subsubsection">
4416 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4417</div>
4418<div class="doc_text">
4419<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4420<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]4421<h5>Overview:</h5>
4422<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4423element-wise comparison of its two floating point vector operands. The output
4424elements have the same width as the input elements.</p>
4425<h5>Arguments:</h5>
4426<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4427the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4428a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4429<ol>
4430 <li><tt>false</tt>: no comparison, always returns false</li>
4431 <li><tt>oeq</tt>: ordered and equal</li>
4432 <li><tt>ogt</tt>: ordered and greater than </li>
4433 <li><tt>oge</tt>: ordered and greater than or equal</li>
4434 <li><tt>olt</tt>: ordered and less than </li>
4435 <li><tt>ole</tt>: ordered and less than or equal</li>
4436 <li><tt>one</tt>: ordered and not equal</li>
4437 <li><tt>ord</tt>: ordered (no nans)</li>
4438 <li><tt>ueq</tt>: unordered or equal</li>
4439 <li><tt>ugt</tt>: unordered or greater than </li>
4440 <li><tt>uge</tt>: unordered or greater than or equal</li>
4441 <li><tt>ult</tt>: unordered or less than </li>
4442 <li><tt>ule</tt>: unordered or less than or equal</li>
4443 <li><tt>une</tt>: unordered or not equal</li>
4444 <li><tt>uno</tt>: unordered (either nans)</li>
4445 <li><tt>true</tt>: no comparison, always returns true</li>
4446</ol>
4447<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4448<a href="#t_floating">floating point</a> typed. They must also be identical
4449types.</p>
4450<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4451<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4452according to the condition code given as <tt>cond</tt>. The comparison yields a
4453<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4454an identical number of elements as the values being compared, and each element
4455having identical with to the width of the floating point elements. The most
4456significant bit in each element is 1 if the element-wise comparison evaluates to
4457true, and is 0 otherwise. All other bits of the result are undefined. The
4458condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4459<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4460
4461<h5>Example:</h5>
4462<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4463 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4464 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4465
4466 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4467 &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]4468</pre>
4469</div>
4470
4471<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4472<div class="doc_subsubsection">
4473 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4474</div>
4475
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4476<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4477
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4478<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4479
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4480<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4481<h5>Overview:</h5>
4482<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4483the SSA graph representing the function.</p>
4484<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4485
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4486<p>The type of the incoming values is specified with the first type
4487field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4488as arguments, with one pair for each predecessor basic block of the
4489current block. Only values of <a href="#t_firstclass">first class</a>
4490type may be used as the value arguments to the PHI node. Only labels
4491may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4492
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4493<p>There must be no non-phi instructions between the start of a basic
4494block and the PHI instructions: i.e. PHI instructions must be first in
4495a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4496
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4497<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4498
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4499<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4500specified by the pair corresponding to the predecessor basic block that executed
4501just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4502
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4503<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4504<pre>
4505Loop: ; Infinite loop that counts from 0 on up...
4506 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4507 %nextindvar = add i32 %indvar, 1
4508 br label %Loop
4509</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4510</div>
4511
4512<!-- _______________________________________________________________________ -->
4513<div class="doc_subsubsection">
4514 <a name="i_select">'<tt>select</tt>' Instruction</a>
4515</div>
4516
4517<div class="doc_text">
4518
4519<h5>Syntax:</h5>
4520
4521<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4522 &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>
4523
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4524 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4525</pre>
4526
4527<h5>Overview:</h5>
4528
4529<p>
4530The '<tt>select</tt>' instruction is used to choose one value based on a
4531condition, without branching.
4532</p>
4533
4534
4535<h5>Arguments:</h5>
4536
4537<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4538The '<tt>select</tt>' instruction requires an 'i1' value or
4539a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4540condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4541type. If the val1/val2 are vectors and
4542the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4543individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4544</p>
4545
4546<h5>Semantics:</h5>
4547
4548<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4549If 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]4550value argument; otherwise, it returns the second value argument.
4551</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4552<p>
4553If the condition is a vector of i1, then the value arguments must
4554be vectors of the same size, and the selection is done element
4555by element.
4556</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4557
4558<h5>Example:</h5>
4559
4560<pre>
4561 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4562</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4563
4564<p>Note that the code generator does not yet support conditions
4565 with vector type.</p>
4566
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4567</div>
4568
4569
4570<!-- _______________________________________________________________________ -->
4571<div class="doc_subsubsection">
4572 <a name="i_call">'<tt>call</tt>' Instruction</a>
4573</div>
4574
4575<div class="doc_text">
4576
4577<h5>Syntax:</h5>
4578<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4579 &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]4580</pre>
4581
4582<h5>Overview:</h5>
4583
4584<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4585
4586<h5>Arguments:</h5>
4587
4588<p>This instruction requires several arguments:</p>
4589
4590<ol>
4591 <li>
4592 <p>The optional "tail" marker indicates whether the callee function accesses
4593 any allocas or varargs in the caller. If the "tail" marker is present, the
4594 function call is eligible for tail call optimization. Note that calls may
4595 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4596 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4597 </li>
4598 <li>
4599 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4600 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4601 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4602 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4603
4604 <li>
4605 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4606 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4607 and '<tt>inreg</tt>' attributes are valid here.</p>
4608 </li>
4609
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4610 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4611 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4612 the type of the return value. Functions that return no value are marked
4613 <tt><a href="#t_void">void</a></tt>.</p>
4614 </li>
4615 <li>
4616 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4617 value being invoked. The argument types must match the types implied by
4618 this signature. This type can be omitted if the function is not varargs
4619 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4620 </li>
4621 <li>
4622 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4623 be invoked. In most cases, this is a direct function invocation, but
4624 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4625 to function value.</p>
4626 </li>
4627 <li>
4628 <p>'<tt>function args</tt>': argument list whose types match the
4629 function signature argument types. All arguments must be of
4630 <a href="#t_firstclass">first class</a> type. If the function signature
4631 indicates the function accepts a variable number of arguments, the extra
4632 arguments can be specified.</p>
4633 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4634 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4635 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4636 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4637 '<tt>readnone</tt>' attributes are valid here.</p>
4638 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4639</ol>
4640
4641<h5>Semantics:</h5>
4642
4643<p>The '<tt>call</tt>' instruction is used to cause control flow to
4644transfer to a specified function, with its incoming arguments bound to
4645the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4646instruction in the called function, control flow continues with the
4647instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4648function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4649
4650<h5>Example:</h5>
4651
4652<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4653 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4654 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4655 %X = tail call i32 @foo() <i>; yields i32</i>
4656 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4657 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4658
4659 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4660 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4661 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4662 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4663 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4664 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4665</pre>
4666
4667</div>
4668
4669<!-- _______________________________________________________________________ -->
4670<div class="doc_subsubsection">
4671 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4672</div>
4673
4674<div class="doc_text">
4675
4676<h5>Syntax:</h5>
4677
4678<pre>
4679 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4680</pre>
4681
4682<h5>Overview:</h5>
4683
4684<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4685the "variable argument" area of a function call. It is used to implement the
4686<tt>va_arg</tt> macro in C.</p>
4687
4688<h5>Arguments:</h5>
4689
4690<p>This instruction takes a <tt>va_list*</tt> value and the type of
4691the argument. It returns a value of the specified argument type and
4692increments the <tt>va_list</tt> to point to the next argument. The
4693actual type of <tt>va_list</tt> is target specific.</p>
4694
4695<h5>Semantics:</h5>
4696
4697<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4698type from the specified <tt>va_list</tt> and causes the
4699<tt>va_list</tt> to point to the next argument. For more information,
4700see the variable argument handling <a href="#int_varargs">Intrinsic
4701Functions</a>.</p>
4702
4703<p>It is legal for this instruction to be called in a function which does not
4704take a variable number of arguments, for example, the <tt>vfprintf</tt>
4705function.</p>
4706
4707<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4708href="#intrinsics">intrinsic function</a> because it takes a type as an
4709argument.</p>
4710
4711<h5>Example:</h5>
4712
4713<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4714
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]4715<p>Note that the code generator does not yet fully support va_arg
4716 on many targets. Also, it does not currently support va_arg with
4717 aggregate types on any target.</p>
4718
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4719</div>
4720
4721<!-- *********************************************************************** -->
4722<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4723<!-- *********************************************************************** -->
4724
4725<div class="doc_text">
4726
4727<p>LLVM supports the notion of an "intrinsic function". These functions have
4728well known names and semantics and are required to follow certain restrictions.
4729Overall, these intrinsics represent an extension mechanism for the LLVM
4730language that does not require changing all of the transformations in LLVM when
4731adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4732
4733<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4734prefix is reserved in LLVM for intrinsic names; thus, function names may not
4735begin with this prefix. Intrinsic functions must always be external functions:
4736you cannot define the body of intrinsic functions. Intrinsic functions may
4737only be used in call or invoke instructions: it is illegal to take the address
4738of an intrinsic function. Additionally, because intrinsic functions are part
4739of the LLVM language, it is required if any are added that they be documented
4740here.</p>
4741
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4742<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4743a family of functions that perform the same operation but on different data
4744types. Because LLVM can represent over 8 million different integer types,
4745overloading is used commonly to allow an intrinsic function to operate on any
4746integer type. One or more of the argument types or the result type can be
4747overloaded to accept any integer type. Argument types may also be defined as
4748exactly matching a previous argument's type or the result type. This allows an
4749intrinsic function which accepts multiple arguments, but needs all of them to
4750be of the same type, to only be overloaded with respect to a single argument or
4751the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4752
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4753<p>Overloaded intrinsics will have the names of its overloaded argument types
4754encoded into its function name, each preceded by a period. Only those types
4755which are overloaded result in a name suffix. Arguments whose type is matched
4756against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4757take an integer of any width and returns an integer of exactly the same integer
4758width. This leads to a family of functions such as
4759<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4760Only one type, the return type, is overloaded, and only one type suffix is
4761required. Because the argument's type is matched against the return type, it
4762does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4763
4764<p>To learn how to add an intrinsic function, please see the
4765<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4766</p>
4767
4768</div>
4769
4770<!-- ======================================================================= -->
4771<div class="doc_subsection">
4772 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4773</div>
4774
4775<div class="doc_text">
4776
4777<p>Variable argument support is defined in LLVM with the <a
4778 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4779intrinsic functions. These functions are related to the similarly
4780named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4781
4782<p>All of these functions operate on arguments that use a
4783target-specific value type "<tt>va_list</tt>". The LLVM assembly
4784language reference manual does not define what this type is, so all
4785transformations should be prepared to handle these functions regardless of
4786the type used.</p>
4787
4788<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4789instruction and the variable argument handling intrinsic functions are
4790used.</p>
4791
4792<div class="doc_code">
4793<pre>
4794define i32 @test(i32 %X, ...) {
4795 ; Initialize variable argument processing
4796 %ap = alloca i8*
4797 %ap2 = bitcast i8** %ap to i8*
4798 call void @llvm.va_start(i8* %ap2)
4799
4800 ; Read a single integer argument
4801 %tmp = va_arg i8** %ap, i32
4802
4803 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4804 %aq = alloca i8*
4805 %aq2 = bitcast i8** %aq to i8*
4806 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4807 call void @llvm.va_end(i8* %aq2)
4808
4809 ; Stop processing of arguments.
4810 call void @llvm.va_end(i8* %ap2)
4811 ret i32 %tmp
4812}
4813
4814declare void @llvm.va_start(i8*)
4815declare void @llvm.va_copy(i8*, i8*)
4816declare void @llvm.va_end(i8*)
4817</pre>
4818</div>
4819
4820</div>
4821
4822<!-- _______________________________________________________________________ -->
4823<div class="doc_subsubsection">
4824 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4825</div>
4826
4827
4828<div class="doc_text">
4829<h5>Syntax:</h5>
4830<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4831<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4832<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4833<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4834href="#i_va_arg">va_arg</a></tt>.</p>
4835
4836<h5>Arguments:</h5>
4837
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4838<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]4839
4840<h5>Semantics:</h5>
4841
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4842<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]4843macro available in C. In a target-dependent way, it initializes the
4844<tt>va_list</tt> element to which the argument points, so that the next call to
4845<tt>va_arg</tt> will produce the first variable argument passed to the function.
4846Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4847last argument of the function as the compiler can figure that out.</p>
4848
4849</div>
4850
4851<!-- _______________________________________________________________________ -->
4852<div class="doc_subsubsection">
4853 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4854</div>
4855
4856<div class="doc_text">
4857<h5>Syntax:</h5>
4858<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4859<h5>Overview:</h5>
4860
4861<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4862which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4863or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4864
4865<h5>Arguments:</h5>
4866
4867<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4868
4869<h5>Semantics:</h5>
4870
4871<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4872macro available in C. In a target-dependent way, it destroys the
4873<tt>va_list</tt> element to which the argument points. Calls to <a
4874href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4875<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4876<tt>llvm.va_end</tt>.</p>
4877
4878</div>
4879
4880<!-- _______________________________________________________________________ -->
4881<div class="doc_subsubsection">
4882 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4883</div>
4884
4885<div class="doc_text">
4886
4887<h5>Syntax:</h5>
4888
4889<pre>
4890 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4891</pre>
4892
4893<h5>Overview:</h5>
4894
4895<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4896from the source argument list to the destination argument list.</p>
4897
4898<h5>Arguments:</h5>
4899
4900<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4901The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4902
4903
4904<h5>Semantics:</h5>
4905
4906<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4907macro available in C. In a target-dependent way, it copies the source
4908<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4909intrinsic is necessary because the <tt><a href="#int_va_start">
4910llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4911example, memory allocation.</p>
4912
4913</div>
4914
4915<!-- ======================================================================= -->
4916<div class="doc_subsection">
4917 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4918</div>
4919
4920<div class="doc_text">
4921
4922<p>
4923LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4924Collection</a> (GC) requires the implementation and generation of these
4925intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4926These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4927stack</a>, as well as garbage collector implementations that require <a
4928href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4929Front-ends for type-safe garbage collected languages should generate these
4930intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4931href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4932</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4933
4934<p>The garbage collection intrinsics only operate on objects in the generic
4935 address space (address space zero).</p>
4936
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4937</div>
4938
4939<!-- _______________________________________________________________________ -->
4940<div class="doc_subsubsection">
4941 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4942</div>
4943
4944<div class="doc_text">
4945
4946<h5>Syntax:</h5>
4947
4948<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4949 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4950</pre>
4951
4952<h5>Overview:</h5>
4953
4954<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4955the code generator, and allows some metadata to be associated with it.</p>
4956
4957<h5>Arguments:</h5>
4958
4959<p>The first argument specifies the address of a stack object that contains the
4960root pointer. The second pointer (which must be either a constant or a global
4961value address) contains the meta-data to be associated with the root.</p>
4962
4963<h5>Semantics:</h5>
4964
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4965<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]4966location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4967the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4968intrinsic may only be used in a function which <a href="#gc">specifies a GC
4969algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4970
4971</div>
4972
4973
4974<!-- _______________________________________________________________________ -->
4975<div class="doc_subsubsection">
4976 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4977</div>
4978
4979<div class="doc_text">
4980
4981<h5>Syntax:</h5>
4982
4983<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4984 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4985</pre>
4986
4987<h5>Overview:</h5>
4988
4989<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4990locations, allowing garbage collector implementations that require read
4991barriers.</p>
4992
4993<h5>Arguments:</h5>
4994
4995<p>The second argument is the address to read from, which should be an address
4996allocated from the garbage collector. The first object is a pointer to the
4997start of the referenced object, if needed by the language runtime (otherwise
4998null).</p>
4999
5000<h5>Semantics:</h5>
5001
5002<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
5003instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5004garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5005may only be used in a function which <a href="#gc">specifies a GC
5006algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5007
5008</div>
5009
5010
5011<!-- _______________________________________________________________________ -->
5012<div class="doc_subsubsection">
5013 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5014</div>
5015
5016<div class="doc_text">
5017
5018<h5>Syntax:</h5>
5019
5020<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5021 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5022</pre>
5023
5024<h5>Overview:</h5>
5025
5026<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
5027locations, allowing garbage collector implementations that require write
5028barriers (such as generational or reference counting collectors).</p>
5029
5030<h5>Arguments:</h5>
5031
5032<p>The first argument is the reference to store, the second is the start of the
5033object to store it to, and the third is the address of the field of Obj to
5034store to. If the runtime does not require a pointer to the object, Obj may be
5035null.</p>
5036
5037<h5>Semantics:</h5>
5038
5039<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
5040instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5041garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5042may only be used in a function which <a href="#gc">specifies a GC
5043algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5044
5045</div>
5046
5047
5048
5049<!-- ======================================================================= -->
5050<div class="doc_subsection">
5051 <a name="int_codegen">Code Generator Intrinsics</a>
5052</div>
5053
5054<div class="doc_text">
5055<p>
5056These intrinsics are provided by LLVM to expose special features that may only
5057be implemented with code generator support.
5058</p>
5059
5060</div>
5061
5062<!-- _______________________________________________________________________ -->
5063<div class="doc_subsubsection">
5064 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5065</div>
5066
5067<div class="doc_text">
5068
5069<h5>Syntax:</h5>
5070<pre>
5071 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5072</pre>
5073
5074<h5>Overview:</h5>
5075
5076<p>
5077The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5078target-specific value indicating the return address of the current function
5079or one of its callers.
5080</p>
5081
5082<h5>Arguments:</h5>
5083
5084<p>
5085The argument to this intrinsic indicates which function to return the address
5086for. Zero indicates the calling function, one indicates its caller, etc. The
5087argument is <b>required</b> to be a constant integer value.
5088</p>
5089
5090<h5>Semantics:</h5>
5091
5092<p>
5093The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
5094the return address of the specified call frame, or zero if it cannot be
5095identified. The value returned by this intrinsic is likely to be incorrect or 0
5096for arguments other than zero, so it should only be used for debugging purposes.
5097</p>
5098
5099<p>
5100Note that calling this intrinsic does not prevent function inlining or other
5101aggressive transformations, so the value returned may not be that of the obvious
5102source-language caller.
5103</p>
5104</div>
5105
5106
5107<!-- _______________________________________________________________________ -->
5108<div class="doc_subsubsection">
5109 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5110</div>
5111
5112<div class="doc_text">
5113
5114<h5>Syntax:</h5>
5115<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5116 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5117</pre>
5118
5119<h5>Overview:</h5>
5120
5121<p>
5122The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5123target-specific frame pointer value for the specified stack frame.
5124</p>
5125
5126<h5>Arguments:</h5>
5127
5128<p>
5129The argument to this intrinsic indicates which function to return the frame
5130pointer for. Zero indicates the calling function, one indicates its caller,
5131etc. The argument is <b>required</b> to be a constant integer value.
5132</p>
5133
5134<h5>Semantics:</h5>
5135
5136<p>
5137The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
5138the frame address of the specified call frame, or zero if it cannot be
5139identified. The value returned by this intrinsic is likely to be incorrect or 0
5140for arguments other than zero, so it should only be used for debugging purposes.
5141</p>
5142
5143<p>
5144Note that calling this intrinsic does not prevent function inlining or other
5145aggressive transformations, so the value returned may not be that of the obvious
5146source-language caller.
5147</p>
5148</div>
5149
5150<!-- _______________________________________________________________________ -->
5151<div class="doc_subsubsection">
5152 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5153</div>
5154
5155<div class="doc_text">
5156
5157<h5>Syntax:</h5>
5158<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5159 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5160</pre>
5161
5162<h5>Overview:</h5>
5163
5164<p>
5165The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
5166the function stack, for use with <a href="#int_stackrestore">
5167<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
5168features like scoped automatic variable sized arrays in C99.
5169</p>
5170
5171<h5>Semantics:</h5>
5172
5173<p>
5174This intrinsic returns a opaque pointer value that can be passed to <a
5175href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
5176<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
5177<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
5178state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
5179practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
5180that were allocated after the <tt>llvm.stacksave</tt> was executed.
5181</p>
5182
5183</div>
5184
5185<!-- _______________________________________________________________________ -->
5186<div class="doc_subsubsection">
5187 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5188</div>
5189
5190<div class="doc_text">
5191
5192<h5>Syntax:</h5>
5193<pre>
5194 declare void @llvm.stackrestore(i8 * %ptr)
5195</pre>
5196
5197<h5>Overview:</h5>
5198
5199<p>
5200The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5201the function stack to the state it was in when the corresponding <a
5202href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
5203useful for implementing language features like scoped automatic variable sized
5204arrays in C99.
5205</p>
5206
5207<h5>Semantics:</h5>
5208
5209<p>
5210See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
5211</p>
5212
5213</div>
5214
5215
5216<!-- _______________________________________________________________________ -->
5217<div class="doc_subsubsection">
5218 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5219</div>
5220
5221<div class="doc_text">
5222
5223<h5>Syntax:</h5>
5224<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5225 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]5226</pre>
5227
5228<h5>Overview:</h5>
5229
5230
5231<p>
5232The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
5233a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
5234no
5235effect on the behavior of the program but can change its performance
5236characteristics.
5237</p>
5238
5239<h5>Arguments:</h5>
5240
5241<p>
5242<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
5243determining if the fetch should be for a read (0) or write (1), and
5244<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5245locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
5246<tt>locality</tt> arguments must be constant integers.
5247</p>
5248
5249<h5>Semantics:</h5>
5250
5251<p>
5252This intrinsic does not modify the behavior of the program. In particular,
5253prefetches cannot trap and do not produce a value. On targets that support this
5254intrinsic, the prefetch can provide hints to the processor cache for better
5255performance.
5256</p>
5257
5258</div>
5259
5260<!-- _______________________________________________________________________ -->
5261<div class="doc_subsubsection">
5262 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5263</div>
5264
5265<div class="doc_text">
5266
5267<h5>Syntax:</h5>
5268<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5269 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5270</pre>
5271
5272<h5>Overview:</h5>
5273
5274
5275<p>
5276The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5277(PC) in a region of
5278code to simulators and other tools. The method is target specific, but it is
5279expected that the marker will use exported symbols to transmit the PC of the
5280marker.
5281The marker makes no guarantees that it will remain with any specific instruction
5282after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5283optimizations. The intended use is to be inserted after optimizations to allow
5284correlations of simulation runs.
5285</p>
5286
5287<h5>Arguments:</h5>
5288
5289<p>
5290<tt>id</tt> is a numerical id identifying the marker.
5291</p>
5292
5293<h5>Semantics:</h5>
5294
5295<p>
5296This intrinsic does not modify the behavior of the program. Backends that do not
5297support this intrinisic may ignore it.
5298</p>
5299
5300</div>
5301
5302<!-- _______________________________________________________________________ -->
5303<div class="doc_subsubsection">
5304 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5305</div>
5306
5307<div class="doc_text">
5308
5309<h5>Syntax:</h5>
5310<pre>
5311 declare i64 @llvm.readcyclecounter( )
5312</pre>
5313
5314<h5>Overview:</h5>
5315
5316
5317<p>
5318The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5319counter register (or similar low latency, high accuracy clocks) on those targets
5320that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5321As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5322should only be used for small timings.
5323</p>
5324
5325<h5>Semantics:</h5>
5326
5327<p>
5328When directly supported, reading the cycle counter should not modify any memory.
5329Implementations are allowed to either return a application specific value or a
5330system wide value. On backends without support, this is lowered to a constant 0.
5331</p>
5332
5333</div>
5334
5335<!-- ======================================================================= -->
5336<div class="doc_subsection">
5337 <a name="int_libc">Standard C Library Intrinsics</a>
5338</div>
5339
5340<div class="doc_text">
5341<p>
5342LLVM provides intrinsics for a few important standard C library functions.
5343These intrinsics allow source-language front-ends to pass information about the
5344alignment of the pointer arguments to the code generator, providing opportunity
5345for more efficient code generation.
5346</p>
5347
5348</div>
5349
5350<!-- _______________________________________________________________________ -->
5351<div class="doc_subsubsection">
5352 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5353</div>
5354
5355<div class="doc_text">
5356
5357<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5358<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5359width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5360<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5361 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5362 i8 &lt;len&gt;, i32 &lt;align&gt;)
5363 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5364 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5365 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5366 i32 &lt;len&gt;, i32 &lt;align&gt;)
5367 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5368 i64 &lt;len&gt;, i32 &lt;align&gt;)
5369</pre>
5370
5371<h5>Overview:</h5>
5372
5373<p>
5374The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5375location to the destination location.
5376</p>
5377
5378<p>
5379Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5380intrinsics do not return a value, and takes an extra alignment argument.
5381</p>
5382
5383<h5>Arguments:</h5>
5384
5385<p>
5386The first argument is a pointer to the destination, the second is a pointer to
5387the source. The third argument is an integer argument
5388specifying the number of bytes to copy, and the fourth argument is the alignment
5389of the source and destination locations.
5390</p>
5391
5392<p>
5393If the call to this intrinisic has an alignment value that is not 0 or 1, then
5394the caller guarantees that both the source and destination pointers are aligned
5395to that boundary.
5396</p>
5397
5398<h5>Semantics:</h5>
5399
5400<p>
5401The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5402location to the destination location, which are not allowed to overlap. It
5403copies "len" bytes of memory over. If the argument is known to be aligned to
5404some boundary, this can be specified as the fourth argument, otherwise it should
5405be set to 0 or 1.
5406</p>
5407</div>
5408
5409
5410<!-- _______________________________________________________________________ -->
5411<div class="doc_subsubsection">
5412 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5413</div>
5414
5415<div class="doc_text">
5416
5417<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5418<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5419width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5420<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5421 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5422 i8 &lt;len&gt;, i32 &lt;align&gt;)
5423 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5424 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5425 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5426 i32 &lt;len&gt;, i32 &lt;align&gt;)
5427 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5428 i64 &lt;len&gt;, i32 &lt;align&gt;)
5429</pre>
5430
5431<h5>Overview:</h5>
5432
5433<p>
5434The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5435location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5436'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5437</p>
5438
5439<p>
5440Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5441intrinsics do not return a value, and takes an extra alignment argument.
5442</p>
5443
5444<h5>Arguments:</h5>
5445
5446<p>
5447The first argument is a pointer to the destination, the second is a pointer to
5448the source. The third argument is an integer argument
5449specifying the number of bytes to copy, and the fourth argument is the alignment
5450of the source and destination locations.
5451</p>
5452
5453<p>
5454If the call to this intrinisic has an alignment value that is not 0 or 1, then
5455the caller guarantees that the source and destination pointers are aligned to
5456that boundary.
5457</p>
5458
5459<h5>Semantics:</h5>
5460
5461<p>
5462The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5463location to the destination location, which may overlap. It
5464copies "len" bytes of memory over. If the argument is known to be aligned to
5465some boundary, this can be specified as the fourth argument, otherwise it should
5466be set to 0 or 1.
5467</p>
5468</div>
5469
5470
5471<!-- _______________________________________________________________________ -->
5472<div class="doc_subsubsection">
5473 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5474</div>
5475
5476<div class="doc_text">
5477
5478<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5479<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5480width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5481<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5482 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5483 i8 &lt;len&gt;, i32 &lt;align&gt;)
5484 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5485 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5486 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5487 i32 &lt;len&gt;, i32 &lt;align&gt;)
5488 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5489 i64 &lt;len&gt;, i32 &lt;align&gt;)
5490</pre>
5491
5492<h5>Overview:</h5>
5493
5494<p>
5495The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5496byte value.
5497</p>
5498
5499<p>
5500Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5501does not return a value, and takes an extra alignment argument.
5502</p>
5503
5504<h5>Arguments:</h5>
5505
5506<p>
5507The first argument is a pointer to the destination to fill, the second is the
5508byte value to fill it with, the third argument is an integer
5509argument specifying the number of bytes to fill, and the fourth argument is the
5510known alignment of destination location.
5511</p>
5512
5513<p>
5514If the call to this intrinisic has an alignment value that is not 0 or 1, then
5515the caller guarantees that the destination pointer is aligned to that boundary.
5516</p>
5517
5518<h5>Semantics:</h5>
5519
5520<p>
5521The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5522the
5523destination location. If the argument is known to be aligned to some boundary,
5524this can be specified as the fourth argument, otherwise it should be set to 0 or
55251.
5526</p>
5527</div>
5528
5529
5530<!-- _______________________________________________________________________ -->
5531<div class="doc_subsubsection">
5532 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5533</div>
5534
5535<div class="doc_text">
5536
5537<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5538<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]5539floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5540types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5541<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5542 declare float @llvm.sqrt.f32(float %Val)
5543 declare double @llvm.sqrt.f64(double %Val)
5544 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5545 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5546 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5547</pre>
5548
5549<h5>Overview:</h5>
5550
5551<p>
5552The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5553returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5554<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5555negative numbers other than -0.0 (which allows for better optimization, because
5556there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5557defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5558</p>
5559
5560<h5>Arguments:</h5>
5561
5562<p>
5563The argument and return value are floating point numbers of the same type.
5564</p>
5565
5566<h5>Semantics:</h5>
5567
5568<p>
5569This function returns the sqrt of the specified operand if it is a nonnegative
5570floating point number.
5571</p>
5572</div>
5573
5574<!-- _______________________________________________________________________ -->
5575<div class="doc_subsubsection">
5576 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5577</div>
5578
5579<div class="doc_text">
5580
5581<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5582<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]5583floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5584types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5585<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5586 declare float @llvm.powi.f32(float %Val, i32 %power)
5587 declare double @llvm.powi.f64(double %Val, i32 %power)
5588 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5589 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5590 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5591</pre>
5592
5593<h5>Overview:</h5>
5594
5595<p>
5596The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5597specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5598multiplications is not defined. When a vector of floating point type is
5599used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5600</p>
5601
5602<h5>Arguments:</h5>
5603
5604<p>
5605The second argument is an integer power, and the first is a value to raise to
5606that power.
5607</p>
5608
5609<h5>Semantics:</h5>
5610
5611<p>
5612This function returns the first value raised to the second power with an
5613unspecified sequence of rounding operations.</p>
5614</div>
5615
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5616<!-- _______________________________________________________________________ -->
5617<div class="doc_subsubsection">
5618 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5619</div>
5620
5621<div class="doc_text">
5622
5623<h5>Syntax:</h5>
5624<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5625floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5626types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5627<pre>
5628 declare float @llvm.sin.f32(float %Val)
5629 declare double @llvm.sin.f64(double %Val)
5630 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5631 declare fp128 @llvm.sin.f128(fp128 %Val)
5632 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5633</pre>
5634
5635<h5>Overview:</h5>
5636
5637<p>
5638The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5639</p>
5640
5641<h5>Arguments:</h5>
5642
5643<p>
5644The argument and return value are floating point numbers of the same type.
5645</p>
5646
5647<h5>Semantics:</h5>
5648
5649<p>
5650This function returns the sine of the specified operand, returning the
5651same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5652conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5653</div>
5654
5655<!-- _______________________________________________________________________ -->
5656<div class="doc_subsubsection">
5657 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5658</div>
5659
5660<div class="doc_text">
5661
5662<h5>Syntax:</h5>
5663<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5664floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5665types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5666<pre>
5667 declare float @llvm.cos.f32(float %Val)
5668 declare double @llvm.cos.f64(double %Val)
5669 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5670 declare fp128 @llvm.cos.f128(fp128 %Val)
5671 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5672</pre>
5673
5674<h5>Overview:</h5>
5675
5676<p>
5677The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5678</p>
5679
5680<h5>Arguments:</h5>
5681
5682<p>
5683The argument and return value are floating point numbers of the same type.
5684</p>
5685
5686<h5>Semantics:</h5>
5687
5688<p>
5689This function returns the cosine of the specified operand, returning the
5690same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5691conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5692</div>
5693
5694<!-- _______________________________________________________________________ -->
5695<div class="doc_subsubsection">
5696 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5697</div>
5698
5699<div class="doc_text">
5700
5701<h5>Syntax:</h5>
5702<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5703floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5704types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5705<pre>
5706 declare float @llvm.pow.f32(float %Val, float %Power)
5707 declare double @llvm.pow.f64(double %Val, double %Power)
5708 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5709 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5710 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5711</pre>
5712
5713<h5>Overview:</h5>
5714
5715<p>
5716The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5717specified (positive or negative) power.
5718</p>
5719
5720<h5>Arguments:</h5>
5721
5722<p>
5723The second argument is a floating point power, and the first is a value to
5724raise to that power.
5725</p>
5726
5727<h5>Semantics:</h5>
5728
5729<p>
5730This function returns the first value raised to the second power,
5731returning the
5732same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5733conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5734</div>
5735
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5736
5737<!-- ======================================================================= -->
5738<div class="doc_subsection">
5739 <a name="int_manip">Bit Manipulation Intrinsics</a>
5740</div>
5741
5742<div class="doc_text">
5743<p>
5744LLVM provides intrinsics for a few important bit manipulation operations.
5745These allow efficient code generation for some algorithms.
5746</p>
5747
5748</div>
5749
5750<!-- _______________________________________________________________________ -->
5751<div class="doc_subsubsection">
5752 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5753</div>
5754
5755<div class="doc_text">
5756
5757<h5>Syntax:</h5>
5758<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5759type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5760<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5761 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5762 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5763 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5764</pre>
5765
5766<h5>Overview:</h5>
5767
5768<p>
5769The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5770values with an even number of bytes (positive multiple of 16 bits). These are
5771useful for performing operations on data that is not in the target's native
5772byte order.
5773</p>
5774
5775<h5>Semantics:</h5>
5776
5777<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5778The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5779and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5780intrinsic returns an i32 value that has the four bytes of the input i32
5781swapped, 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]5782i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5783<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5784additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5785</p>
5786
5787</div>
5788
5789<!-- _______________________________________________________________________ -->
5790<div class="doc_subsubsection">
5791 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5792</div>
5793
5794<div class="doc_text">
5795
5796<h5>Syntax:</h5>
5797<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]5798width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5799<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5800 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5801 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5802 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5803 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5804 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5805</pre>
5806
5807<h5>Overview:</h5>
5808
5809<p>
5810The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5811value.
5812</p>
5813
5814<h5>Arguments:</h5>
5815
5816<p>
5817The only argument is the value to be counted. The argument may be of any
5818integer type. The return type must match the argument type.
5819</p>
5820
5821<h5>Semantics:</h5>
5822
5823<p>
5824The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5825</p>
5826</div>
5827
5828<!-- _______________________________________________________________________ -->
5829<div class="doc_subsubsection">
5830 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5831</div>
5832
5833<div class="doc_text">
5834
5835<h5>Syntax:</h5>
5836<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]5837integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5838<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5839 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5840 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5841 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5842 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5843 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5844</pre>
5845
5846<h5>Overview:</h5>
5847
5848<p>
5849The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5850leading zeros in a variable.
5851</p>
5852
5853<h5>Arguments:</h5>
5854
5855<p>
5856The only argument is the value to be counted. The argument may be of any
5857integer type. The return type must match the argument type.
5858</p>
5859
5860<h5>Semantics:</h5>
5861
5862<p>
5863The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5864in a variable. If the src == 0 then the result is the size in bits of the type
5865of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5866</p>
5867</div>
5868
5869
5870
5871<!-- _______________________________________________________________________ -->
5872<div class="doc_subsubsection">
5873 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5874</div>
5875
5876<div class="doc_text">
5877
5878<h5>Syntax:</h5>
5879<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]5880integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5881<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5882 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5883 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5884 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5885 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5886 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5887</pre>
5888
5889<h5>Overview:</h5>
5890
5891<p>
5892The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5893trailing zeros.
5894</p>
5895
5896<h5>Arguments:</h5>
5897
5898<p>
5899The only argument is the value to be counted. The argument may be of any
5900integer type. The return type must match the argument type.
5901</p>
5902
5903<h5>Semantics:</h5>
5904
5905<p>
5906The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5907in a variable. If the src == 0 then the result is the size in bits of the type
5908of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5909</p>
5910</div>
5911
5912<!-- _______________________________________________________________________ -->
5913<div class="doc_subsubsection">
5914 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5915</div>
5916
5917<div class="doc_text">
5918
5919<h5>Syntax:</h5>
5920<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5921on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5922<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5923 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5924 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5925</pre>
5926
5927<h5>Overview:</h5>
5928<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5929range of bits from an integer value and returns them in the same bit width as
5930the original value.</p>
5931
5932<h5>Arguments:</h5>
5933<p>The first argument, <tt>%val</tt> and the result may be integer types of
5934any bit width but they must have the same bit width. The second and third
5935arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5936
5937<h5>Semantics:</h5>
5938<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5939of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5940<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5941operates in forward mode.</p>
5942<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5943right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5944only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5945<ol>
5946 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5947 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5948 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5949 to determine the number of bits to retain.</li>
5950 <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]5951 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5952</ol>
5953<p>In reverse mode, a similar computation is made except that the bits are
5954returned in the reverse order. So, for example, if <tt>X</tt> has the value
5955<tt>i16 0x0ACF (101011001111)</tt> and we apply
5956<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5957<tt>i16 0x0026 (000000100110)</tt>.</p>
5958</div>
5959
5960<div class="doc_subsubsection">
5961 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5962</div>
5963
5964<div class="doc_text">
5965
5966<h5>Syntax:</h5>
5967<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5968on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5969<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5970 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5971 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]5972</pre>
5973
5974<h5>Overview:</h5>
5975<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5976of bits in an integer value with another integer value. It returns the integer
5977with the replaced bits.</p>
5978
5979<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5980<p>The first argument, <tt>%val</tt>, and the result may be integer types of
5981any 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]5982whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5983integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5984type since they specify only a bit index.</p>
5985
5986<h5>Semantics:</h5>
5987<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5988of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5989<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5990operates in forward mode.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5991
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5992<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5993truncating it down to the size of the replacement area or zero extending it
5994up to that size.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5995
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5996<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5997are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5998in <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]5999to the <tt>%hi</tt>th bit.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6000
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6001<p>In reverse mode, a similar computation is made except that the bits are
6002reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6003<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]6004
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6005<h5>Examples:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6006
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6007<pre>
6008 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
6009 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
6010 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
6011 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
6012 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
6013</pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6014
6015</div>
6016
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6017<!-- ======================================================================= -->
6018<div class="doc_subsection">
6019 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6020</div>
6021
6022<div class="doc_text">
6023<p>
6024LLVM provides intrinsics for some arithmetic with overflow operations.
6025</p>
6026
6027</div>
6028
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6029<!-- _______________________________________________________________________ -->
6030<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6031 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6032</div>
6033
6034<div class="doc_text">
6035
6036<h5>Syntax:</h5>
6037
6038<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]6039on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6040
6041<pre>
6042 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6043 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6044 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6045</pre>
6046
6047<h5>Overview:</h5>
6048
6049<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
6050a signed addition of the two arguments, and indicate whether an overflow
6051occurred during the signed summation.</p>
6052
6053<h5>Arguments:</h5>
6054
6055<p>The arguments (%a and %b) and the first element of the result structure may
6056be of integer types of any bit width, but they must have the same bit width. The
6057second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6058and <tt>%b</tt> are the two values that will undergo signed addition.</p>
6059
6060<h5>Semantics:</h5>
6061
6062<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
6063a signed addition of the two variables. They return a structure &mdash; the
6064first element of which is the signed summation, and the second element of which
6065is a bit specifying if the signed summation resulted in an overflow.</p>
6066
6067<h5>Examples:</h5>
6068<pre>
6069 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6070 %sum = extractvalue {i32, i1} %res, 0
6071 %obit = extractvalue {i32, i1} %res, 1
6072 br i1 %obit, label %overflow, label %normal
6073</pre>
6074
6075</div>
6076
6077<!-- _______________________________________________________________________ -->
6078<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6079 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6080</div>
6081
6082<div class="doc_text">
6083
6084<h5>Syntax:</h5>
6085
6086<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]6087on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6088
6089<pre>
6090 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6091 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6092 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6093</pre>
6094
6095<h5>Overview:</h5>
6096
6097<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6098an unsigned addition of the two arguments, and indicate whether a carry occurred
6099during the unsigned summation.</p>
6100
6101<h5>Arguments:</h5>
6102
6103<p>The arguments (%a and %b) and the first element of the result structure may
6104be of integer types of any bit width, but they must have the same bit width. The
6105second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6106and <tt>%b</tt> are the two values that will undergo unsigned addition.</p>
6107
6108<h5>Semantics:</h5>
6109
6110<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6111an unsigned addition of the two arguments. They return a structure &mdash; the
6112first element of which is the sum, and the second element of which is a bit
6113specifying if the unsigned summation resulted in a carry.</p>
6114
6115<h5>Examples:</h5>
6116<pre>
6117 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6118 %sum = extractvalue {i32, i1} %res, 0
6119 %obit = extractvalue {i32, i1} %res, 1
6120 br i1 %obit, label %carry, label %normal
6121</pre>
6122
6123</div>
6124
6125<!-- _______________________________________________________________________ -->
6126<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6127 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6128</div>
6129
6130<div class="doc_text">
6131
6132<h5>Syntax:</h5>
6133
6134<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]6135on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6136
6137<pre>
6138 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6139 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6140 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6141</pre>
6142
6143<h5>Overview:</h5>
6144
6145<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6146a signed subtraction of the two arguments, and indicate whether an overflow
6147occurred during the signed subtraction.</p>
6148
6149<h5>Arguments:</h5>
6150
6151<p>The arguments (%a and %b) and the first element of the result structure may
6152be of integer types of any bit width, but they must have the same bit width. The
6153second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6154and <tt>%b</tt> are the two values that will undergo signed subtraction.</p>
6155
6156<h5>Semantics:</h5>
6157
6158<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6159a signed subtraction of the two arguments. They return a structure &mdash; the
6160first element of which is the subtraction, and the second element of which is a bit
6161specifying if the signed subtraction resulted in an overflow.</p>
6162
6163<h5>Examples:</h5>
6164<pre>
6165 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6166 %sum = extractvalue {i32, i1} %res, 0
6167 %obit = extractvalue {i32, i1} %res, 1
6168 br i1 %obit, label %overflow, label %normal
6169</pre>
6170
6171</div>
6172
6173<!-- _______________________________________________________________________ -->
6174<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6175 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6176</div>
6177
6178<div class="doc_text">
6179
6180<h5>Syntax:</h5>
6181
6182<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]6183on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6184
6185<pre>
6186 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6187 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6188 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6189</pre>
6190
6191<h5>Overview:</h5>
6192
6193<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6194an unsigned subtraction of the two arguments, and indicate whether an overflow
6195occurred during the unsigned subtraction.</p>
6196
6197<h5>Arguments:</h5>
6198
6199<p>The arguments (%a and %b) and the first element of the result structure may
6200be of integer types of any bit width, but they must have the same bit width. The
6201second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6202and <tt>%b</tt> are the two values that will undergo unsigned subtraction.</p>
6203
6204<h5>Semantics:</h5>
6205
6206<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6207an unsigned subtraction of the two arguments. They return a structure &mdash; the
6208first element of which is the subtraction, and the second element of which is a bit
6209specifying if the unsigned subtraction resulted in an overflow.</p>
6210
6211<h5>Examples:</h5>
6212<pre>
6213 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6214 %sum = extractvalue {i32, i1} %res, 0
6215 %obit = extractvalue {i32, i1} %res, 1
6216 br i1 %obit, label %overflow, label %normal
6217</pre>
6218
6219</div>
6220
6221<!-- _______________________________________________________________________ -->
6222<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6223 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6224</div>
6225
6226<div class="doc_text">
6227
6228<h5>Syntax:</h5>
6229
6230<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]6231on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6232
6233<pre>
6234 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6235 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6236 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6237</pre>
6238
6239<h5>Overview:</h5>
6240
6241<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6242a signed multiplication of the two arguments, and indicate whether an overflow
6243occurred during the signed multiplication.</p>
6244
6245<h5>Arguments:</h5>
6246
6247<p>The arguments (%a and %b) and the first element of the result structure may
6248be of integer types of any bit width, but they must have the same bit width. The
6249second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6250and <tt>%b</tt> are the two values that will undergo signed multiplication.</p>
6251
6252<h5>Semantics:</h5>
6253
6254<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6255a signed multiplication of the two arguments. They return a structure &mdash;
6256the first element of which is the multiplication, and the second element of
6257which is a bit specifying if the signed multiplication resulted in an
6258overflow.</p>
6259
6260<h5>Examples:</h5>
6261<pre>
6262 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6263 %sum = extractvalue {i32, i1} %res, 0
6264 %obit = extractvalue {i32, i1} %res, 1
6265 br i1 %obit, label %overflow, label %normal
6266</pre>
6267
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6268</div>
6269
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6270<!-- _______________________________________________________________________ -->
6271<div class="doc_subsubsection">
6272 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6273</div>
6274
6275<div class="doc_text">
6276
6277<h5>Syntax:</h5>
6278
6279<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
6280on any integer bit width.</p>
6281
6282<pre>
6283 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6284 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6285 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6286</pre>
6287
6288<h5>Overview:</h5>
6289
6290<p><i><b>Warning:</b> '<tt>llvm.umul.with.overflow</tt>' is badly broken. It is
6291actively being fixed, but it should not currently be used!</i></p>
6292
6293<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6294a unsigned multiplication of the two arguments, and indicate whether an overflow
6295occurred during the unsigned multiplication.</p>
6296
6297<h5>Arguments:</h5>
6298
6299<p>The arguments (%a and %b) and the first element of the result structure may
6300be of integer types of any bit width, but they must have the same bit width. The
6301second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6302and <tt>%b</tt> are the two values that will undergo unsigned
6303multiplication.</p>
6304
6305<h5>Semantics:</h5>
6306
6307<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6308an unsigned multiplication of the two arguments. They return a structure &mdash;
6309the first element of which is the multiplication, and the second element of
6310which is a bit specifying if the unsigned multiplication resulted in an
6311overflow.</p>
6312
6313<h5>Examples:</h5>
6314<pre>
6315 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6316 %sum = extractvalue {i32, i1} %res, 0
6317 %obit = extractvalue {i32, i1} %res, 1
6318 br i1 %obit, label %overflow, label %normal
6319</pre>
6320
6321</div>
6322
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6323<!-- ======================================================================= -->
6324<div class="doc_subsection">
6325 <a name="int_debugger">Debugger Intrinsics</a>
6326</div>
6327
6328<div class="doc_text">
6329<p>
6330The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
6331are described in the <a
6332href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
6333Debugging</a> document.
6334</p>
6335</div>
6336
6337
6338<!-- ======================================================================= -->
6339<div class="doc_subsection">
6340 <a name="int_eh">Exception Handling Intrinsics</a>
6341</div>
6342
6343<div class="doc_text">
6344<p> The LLVM exception handling intrinsics (which all start with
6345<tt>llvm.eh.</tt> prefix), are described in the <a
6346href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6347Handling</a> document. </p>
6348</div>
6349
6350<!-- ======================================================================= -->
6351<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6352 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6353</div>
6354
6355<div class="doc_text">
6356<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6357 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6358 the <tt>nest</tt> attribute, from a function. The result is a callable
6359 function pointer lacking the nest parameter - the caller does not need
6360 to provide a value for it. Instead, the value to use is stored in
6361 advance in a "trampoline", a block of memory usually allocated
6362 on the stack, which also contains code to splice the nest value into the
6363 argument list. This is used to implement the GCC nested function address
6364 extension.
6365</p>
6366<p>
6367 For example, if the function is
6368 <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]6369 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]6370<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6371 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6372 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6373 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6374 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6375</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]6376 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6377 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6378</div>
6379
6380<!-- _______________________________________________________________________ -->
6381<div class="doc_subsubsection">
6382 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6383</div>
6384<div class="doc_text">
6385<h5>Syntax:</h5>
6386<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6387declare 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]6388</pre>
6389<h5>Overview:</h5>
6390<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6391 This fills the memory pointed to by <tt>tramp</tt> with code
6392 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6393</p>
6394<h5>Arguments:</h5>
6395<p>
6396 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6397 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
6398 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]6399 intrinsic. Note that the size and the alignment are target-specific - LLVM
6400 currently provides no portable way of determining them, so a front-end that
6401 generates this intrinsic needs to have some target-specific knowledge.
6402 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]6403</p>
6404<h5>Semantics:</h5>
6405<p>
6406 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6407 dependent code, turning it into a function. A pointer to this function is
6408 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6409 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6410 before being called. The new function's signature is the same as that of
6411 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
6412 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
6413 of pointer type. Calling the new function is equivalent to calling
6414 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
6415 missing <tt>nest</tt> argument. If, after calling
6416 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
6417 modified, then the effect of any later call to the returned function pointer is
6418 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6419</p>
6420</div>
6421
6422<!-- ======================================================================= -->
6423<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6424 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6425</div>
6426
6427<div class="doc_text">
6428<p>
6429 These intrinsic functions expand the "universal IR" of LLVM to represent
6430 hardware constructs for atomic operations and memory synchronization. This
6431 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]6432 is aimed at a low enough level to allow any programming models or APIs
6433 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6434 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
6435 hardware behavior. Just as hardware provides a "universal IR" for source
6436 languages, it also provides a starting point for developing a "universal"
6437 atomic operation and synchronization IR.
6438</p>
6439<p>
6440 These do <em>not</em> form an API such as high-level threading libraries,
6441 software transaction memory systems, atomic primitives, and intrinsic
6442 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6443 application libraries. The hardware interface provided by LLVM should allow
6444 a clean implementation of all of these APIs and parallel programming models.
6445 No one model or paradigm should be selected above others unless the hardware
6446 itself ubiquitously does so.
6447
6448</p>
6449</div>
6450
6451<!-- _______________________________________________________________________ -->
6452<div class="doc_subsubsection">
6453 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6454</div>
6455<div class="doc_text">
6456<h5>Syntax:</h5>
6457<pre>
6458declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
6459i1 &lt;device&gt; )
6460
6461</pre>
6462<h5>Overview:</h5>
6463<p>
6464 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6465 specific pairs of memory access types.
6466</p>
6467<h5>Arguments:</h5>
6468<p>
6469 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6470 The first four arguments enables a specific barrier as listed below. The fith
6471 argument specifies that the barrier applies to io or device or uncached memory.
6472
6473</p>
6474 <ul>
6475 <li><tt>ll</tt>: load-load barrier</li>
6476 <li><tt>ls</tt>: load-store barrier</li>
6477 <li><tt>sl</tt>: store-load barrier</li>
6478 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6479 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6480 </ul>
6481<h5>Semantics:</h5>
6482<p>
6483 This intrinsic causes the system to enforce some ordering constraints upon
6484 the loads and stores of the program. This barrier does not indicate
6485 <em>when</em> any events will occur, it only enforces an <em>order</em> in
6486 which they occur. For any of the specified pairs of load and store operations
6487 (f.ex. load-load, or store-load), all of the first operations preceding the
6488 barrier will complete before any of the second operations succeeding the
6489 barrier begin. Specifically the semantics for each pairing is as follows:
6490</p>
6491 <ul>
6492 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6493 after the barrier begins.</li>
6494
6495 <li><tt>ls</tt>: All loads before the barrier must complete before any
6496 store after the barrier begins.</li>
6497 <li><tt>ss</tt>: All stores before the barrier must complete before any
6498 store after the barrier begins.</li>
6499 <li><tt>sl</tt>: All stores before the barrier must complete before any
6500 load after the barrier begins.</li>
6501 </ul>
6502<p>
6503 These semantics are applied with a logical "and" behavior when more than one
6504 is enabled in a single memory barrier intrinsic.
6505</p>
6506<p>
6507 Backends may implement stronger barriers than those requested when they do not
6508 support as fine grained a barrier as requested. Some architectures do not
6509 need all types of barriers and on such architectures, these become noops.
6510</p>
6511<h5>Example:</h5>
6512<pre>
6513%ptr = malloc i32
6514 store i32 4, %ptr
6515
6516%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6517 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6518 <i>; guarantee the above finishes</i>
6519 store i32 8, %ptr <i>; before this begins</i>
6520</pre>
6521</div>
6522
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6523<!-- _______________________________________________________________________ -->
6524<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6525 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6526</div>
6527<div class="doc_text">
6528<h5>Syntax:</h5>
6529<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6530 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6531 any integer bit width and for different address spaces. Not all targets
6532 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6533
6534<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6535declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6536declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6537declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6538declare 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]6539
6540</pre>
6541<h5>Overview:</h5>
6542<p>
6543 This loads a value in memory and compares it to a given value. If they are
6544 equal, it stores a new value into the memory.
6545</p>
6546<h5>Arguments:</h5>
6547<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6548 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6549 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6550 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6551 this integer type. While any bit width integer may be used, targets may only
6552 lower representations they support in hardware.
6553
6554</p>
6555<h5>Semantics:</h5>
6556<p>
6557 This entire intrinsic must be executed atomically. It first loads the value
6558 in memory pointed to by <tt>ptr</tt> and compares it with the value
6559 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
6560 loaded value is yielded in all cases. This provides the equivalent of an
6561 atomic compare-and-swap operation within the SSA framework.
6562</p>
6563<h5>Examples:</h5>
6564
6565<pre>
6566%ptr = malloc i32
6567 store i32 4, %ptr
6568
6569%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6570%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6571 <i>; yields {i32}:result1 = 4</i>
6572%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6573%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6574
6575%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6576%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6577 <i>; yields {i32}:result2 = 8</i>
6578%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6579
6580%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6581</pre>
6582</div>
6583
6584<!-- _______________________________________________________________________ -->
6585<div class="doc_subsubsection">
6586 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6587</div>
6588<div class="doc_text">
6589<h5>Syntax:</h5>
6590
6591<p>
6592 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6593 integer bit width. Not all targets support all bit widths however.</p>
6594<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6595declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6596declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6597declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6598declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6599
6600</pre>
6601<h5>Overview:</h5>
6602<p>
6603 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6604 the value from memory. It then stores the value in <tt>val</tt> in the memory
6605 at <tt>ptr</tt>.
6606</p>
6607<h5>Arguments:</h5>
6608
6609<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6610 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6611 <tt>val</tt> argument and the result must be integers of the same bit width.
6612 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6613 integer type. The targets may only lower integer representations they
6614 support.
6615</p>
6616<h5>Semantics:</h5>
6617<p>
6618 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6619 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6620 equivalent of an atomic swap operation within the SSA framework.
6621
6622</p>
6623<h5>Examples:</h5>
6624<pre>
6625%ptr = malloc i32
6626 store i32 4, %ptr
6627
6628%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6629%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6630 <i>; yields {i32}:result1 = 4</i>
6631%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6632%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6633
6634%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6635%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6636 <i>; yields {i32}:result2 = 8</i>
6637
6638%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6639%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6640</pre>
6641</div>
6642
6643<!-- _______________________________________________________________________ -->
6644<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6645 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6646
6647</div>
6648<div class="doc_text">
6649<h5>Syntax:</h5>
6650<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6651 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]6652 integer bit width. Not all targets support all bit widths however.</p>
6653<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6654declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6655declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6656declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6657declare 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]6658
6659</pre>
6660<h5>Overview:</h5>
6661<p>
6662 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6663 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6664</p>
6665<h5>Arguments:</h5>
6666<p>
6667
6668 The intrinsic takes two arguments, the first a pointer to an integer value
6669 and the second an integer value. The result is also an integer value. These
6670 integer types can have any bit width, but they must all have the same bit
6671 width. The targets may only lower integer representations they support.
6672</p>
6673<h5>Semantics:</h5>
6674<p>
6675 This intrinsic does a series of operations atomically. It first loads the
6676 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6677 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6678</p>
6679
6680<h5>Examples:</h5>
6681<pre>
6682%ptr = malloc i32
6683 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6684%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6685 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6686%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6687 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6688%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6689 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6690%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6691</pre>
6692</div>
6693
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6694<!-- _______________________________________________________________________ -->
6695<div class="doc_subsubsection">
6696 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6697
6698</div>
6699<div class="doc_text">
6700<h5>Syntax:</h5>
6701<p>
6702 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]6703 any integer bit width and for different address spaces. Not all targets
6704 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6705<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6706declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6707declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6708declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6709declare 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]6710
6711</pre>
6712<h5>Overview:</h5>
6713<p>
6714 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6715 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6716</p>
6717<h5>Arguments:</h5>
6718<p>
6719
6720 The intrinsic takes two arguments, the first a pointer to an integer value
6721 and the second an integer value. The result is also an integer value. These
6722 integer types can have any bit width, but they must all have the same bit
6723 width. The targets may only lower integer representations they support.
6724</p>
6725<h5>Semantics:</h5>
6726<p>
6727 This intrinsic does a series of operations atomically. It first loads the
6728 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6729 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6730</p>
6731
6732<h5>Examples:</h5>
6733<pre>
6734%ptr = malloc i32
6735 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6736%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6737 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6738%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6739 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6740%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6741 <i>; yields {i32}:result3 = 2</i>
6742%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6743</pre>
6744</div>
6745
6746<!-- _______________________________________________________________________ -->
6747<div class="doc_subsubsection">
6748 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6749 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6750 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6751 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6752
6753</div>
6754<div class="doc_text">
6755<h5>Syntax:</h5>
6756<p>
6757 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6758 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6759 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6760 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6761<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6762declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6763declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6764declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6765declare 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]6766
6767</pre>
6768
6769<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6770declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6771declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6772declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6773declare 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]6774
6775</pre>
6776
6777<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6778declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6779declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6780declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6781declare 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]6782
6783</pre>
6784
6785<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6786declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6787declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6788declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6789declare 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]6790
6791</pre>
6792<h5>Overview:</h5>
6793<p>
6794 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6795 the value stored in memory at <tt>ptr</tt>. It yields the original value
6796 at <tt>ptr</tt>.
6797</p>
6798<h5>Arguments:</h5>
6799<p>
6800
6801 These intrinsics take two arguments, the first a pointer to an integer value
6802 and the second an integer value. The result is also an integer value. These
6803 integer types can have any bit width, but they must all have the same bit
6804 width. The targets may only lower integer representations they support.
6805</p>
6806<h5>Semantics:</h5>
6807<p>
6808 These intrinsics does a series of operations atomically. They first load the
6809 value stored at <tt>ptr</tt>. They then do the bitwise operation
6810 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6811 value stored at <tt>ptr</tt>.
6812</p>
6813
6814<h5>Examples:</h5>
6815<pre>
6816%ptr = malloc i32
6817 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6818%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6819 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6820%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6821 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6822%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6823 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6824%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6825 <i>; yields {i32}:result3 = FF</i>
6826%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6827</pre>
6828</div>
6829
6830
6831<!-- _______________________________________________________________________ -->
6832<div class="doc_subsubsection">
6833 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6834 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6835 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6836 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6837
6838</div>
6839<div class="doc_text">
6840<h5>Syntax:</h5>
6841<p>
6842 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6843 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6844 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6845 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6846 support all bit widths however.</p>
6847<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6848declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6849declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6850declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6851declare 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]6852
6853</pre>
6854
6855<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6856declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6857declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6858declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6859declare 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]6860
6861</pre>
6862
6863<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6864declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6865declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6866declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6867declare 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]6868
6869</pre>
6870
6871<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6872declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6873declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6874declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6875declare 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]6876
6877</pre>
6878<h5>Overview:</h5>
6879<p>
6880 These intrinsics takes the signed or unsigned minimum or maximum of
6881 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6882 original value at <tt>ptr</tt>.
6883</p>
6884<h5>Arguments:</h5>
6885<p>
6886
6887 These intrinsics take two arguments, the first a pointer to an integer value
6888 and the second an integer value. The result is also an integer value. These
6889 integer types can have any bit width, but they must all have the same bit
6890 width. The targets may only lower integer representations they support.
6891</p>
6892<h5>Semantics:</h5>
6893<p>
6894 These intrinsics does a series of operations atomically. They first load the
6895 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6896 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6897 the original value stored at <tt>ptr</tt>.
6898</p>
6899
6900<h5>Examples:</h5>
6901<pre>
6902%ptr = malloc i32
6903 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6904%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6905 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6906%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6907 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6908%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6909 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6910%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6911 <i>; yields {i32}:result3 = 8</i>
6912%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6913</pre>
6914</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6915
6916<!-- ======================================================================= -->
6917<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6918 <a name="int_general">General Intrinsics</a>
6919</div>
6920
6921<div class="doc_text">
6922<p> This class of intrinsics is designed to be generic and has
6923no specific purpose. </p>
6924</div>
6925
6926<!-- _______________________________________________________________________ -->
6927<div class="doc_subsubsection">
6928 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6929</div>
6930
6931<div class="doc_text">
6932
6933<h5>Syntax:</h5>
6934<pre>
6935 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6936</pre>
6937
6938<h5>Overview:</h5>
6939
6940<p>
6941The '<tt>llvm.var.annotation</tt>' intrinsic
6942</p>
6943
6944<h5>Arguments:</h5>
6945
6946<p>
6947The first argument is a pointer to a value, the second is a pointer to a
6948global string, the third is a pointer to a global string which is the source
6949file name, and the last argument is the line number.
6950</p>
6951
6952<h5>Semantics:</h5>
6953
6954<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6955This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6956This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6957annotations. These have no other defined use, they are ignored by code
6958generation and optimization.
6959</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6960</div>
6961
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6962<!-- _______________________________________________________________________ -->
6963<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6964 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6965</div>
6966
6967<div class="doc_text">
6968
6969<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6970<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6971any integer bit width.
6972</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6973<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6974 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6975 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6976 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6977 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6978 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]6979</pre>
6980
6981<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6982
6983<p>
6984The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6985</p>
6986
6987<h5>Arguments:</h5>
6988
6989<p>
6990The first argument is an integer value (result of some expression),
6991the second is a pointer to a global string, the third is a pointer to a global
6992string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6993It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6994</p>
6995
6996<h5>Semantics:</h5>
6997
6998<p>
6999This intrinsic allows annotations to be put on arbitrary expressions
7000with arbitrary strings. This can be useful for special purpose optimizations
7001that want to look for these annotations. These have no other defined use, they
7002are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]7003</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7004</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7005
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7006<!-- _______________________________________________________________________ -->
7007<div class="doc_subsubsection">
7008 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7009</div>
7010
7011<div class="doc_text">
7012
7013<h5>Syntax:</h5>
7014<pre>
7015 declare void @llvm.trap()
7016</pre>
7017
7018<h5>Overview:</h5>
7019
7020<p>
7021The '<tt>llvm.trap</tt>' intrinsic
7022</p>
7023
7024<h5>Arguments:</h5>
7025
7026<p>
7027None
7028</p>
7029
7030<h5>Semantics:</h5>
7031
7032<p>
7033This intrinsics is lowered to the target dependent trap instruction. If the
7034target does not have a trap instruction, this intrinsic will be lowered to the
7035call of the abort() function.
7036</p>
7037</div>
7038
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7039<!-- _______________________________________________________________________ -->
7040<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7041 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7042</div>
7043<div class="doc_text">
7044<h5>Syntax:</h5>
7045<pre>
7046declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
7047
7048</pre>
7049<h5>Overview:</h5>
7050<p>
7051 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
7052 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
7053 it is placed on the stack before local variables.
7054</p>
7055<h5>Arguments:</h5>
7056<p>
7057 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
7058 first argument is the value loaded from the stack guard
7059 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
7060 has enough space to hold the value of the guard.
7061</p>
7062<h5>Semantics:</h5>
7063<p>
7064 This intrinsic causes the prologue/epilogue inserter to force the position of
7065 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7066 stack. This is to ensure that if a local variable on the stack is overwritten,
7067 it will destroy the value of the guard. When the function exits, the guard on
7068 the stack is checked against the original guard. If they're different, then
7069 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
7070</p>
7071</div>
7072
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7073<!-- *********************************************************************** -->
7074<hr>
7075<address>
7076 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7077 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7078 <a href="http://validator.w3.org/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7080
7081 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7082 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7083 Last modified: $Date$
7084</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7085
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7086</body>
7087</html>